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Background: Patients with Ehlers-Danlos syndromes (EDS) often experience high rates of joint subluxations and dislocations, and associated pain that may require surgical interventions. Orthopaedic surgical management is challenging in this population, and patients will often undergo multiple unsuccessful surgeries. Outcomes data specific to patients with EDS are sparse in the orthopaedic surgery literature. We conducted a scoping review to evaluate the evidence and outcomes for orthopaedic surgery specifically for the EDS population., Methods: PubMed MEDLINE, Embase, The Cochrane Library, Cochrane Controlled Register of Trials (CENTRAL), CINHL, and Scopus from their inception to February 28, 2024 for all studies that reported outcomes for orthopaedic surgery in patients with EDS. Two reviewers independently determined study eligibility, rated study quality, and extracted data. Methodology followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). The studies in this scoping review include Level III (retrospective cohort and case control) and Level IV (case series) evidence., Results: The literature search yielded a total of 71 citations published between 1990 and 2023. All were primary studies. 38 were single case studies, 14 were case series, and 19 were retrospective cohort studies. No randomized clinical studies or systematic reviews were identified. Overall, the reported findings for the various anatomical sites and procedures indicated that surgery outcomes were inconsistent. Our review highlights the need for future research to determine whether currently established surgical approaches for various orthopaedic conditions offer long-term clinical benefit in patients with EDS. This is clearly a challenging diagnosis, and more rigorous clinical studies are required to identify optimal treatment approaches., Conclusions: Our review found little evidence-based research to guide optimal surgical treatment in EDS. Established surgical techniques that have been shown to be successful in the wider orthopaedic population should be studied to determine their efficacy in the EDS population., (© 2024. The Author(s).)

Introduction: Patients with Ehlers-Danlos syndromes (EDS) and hypermobility spectrum disorders (HSD) have significant health challenges that are well-documented, however their impact in terms of cost is not known. Our research objective was to examine the cost burden of EDS and HSD in the United States. We focused this analysis on those with commercial insurance plans., Methods: We queried the MarketScan® database for year 2021 for claims that contained an ICD-10 diagnosis code for EDS or hypermobility. Excess costs for patients in the EDS and HSD cohorts were determined by matching each patient to one patient in the database that did not have a claim for EDS or HSD and comparing total costs for the calendar year. We determined whether patients had claims for selected comorbid conditions likely to impact costs during the calendar year., Results: Sample sizes were 5,113 for adult (age ≥ 18) patients with EDS, 4,880 for adult patients with HSD, 1,059 for child (age 5-17) patients with EDS, and 2,427 for child patients with HSD. The mean excess costs were $21,100 for adult EDS patients, $11,600 for adult HSD patients, $17,000 for child EDS patients, and $11,000 for child HSD patients. EDS and HSD cohorts, both adults and children, with any of the comorbidities had greater healthcare costs. The largest difference was found in the EDS cohort with gastrointestinal comorbid conditions, with more than double the costs for adults., Discussion: We found that patients in the MarketScan database, adults and children, who had EDS or HSD had substantially higher associated excess healthcare costs than patients without EDS or HSD when considering age, sex, geographic location, and comorbidities. These disproportionate healthcare costs in this population have health policy and economic implications, including the need for rapid diagnosis, access to treatment, and accelerated research to advance treatments., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Schubart, Schaefer, Knight, Mills and Francomano.)

Background: The Ehlers-Danlos Syndromes (EDS) are a group of connective tissue disorders that are hereditary in nature and characterized by joint hypermobility and tissue fragility. The complex nature of this unique patient population requires multidisciplinary care, but appropriate centers for such care do not exist in large portions of the country. Need for more integrated services has been identified in Chicagoland, or Chicago and its suburbs. In order to explore and begin to address barriers to seeking appropriate care facing EDS patients in this region, we developed an online survey which we circulated through EDS social media groups for Chicagoland patients., Results: Three hundred and nine unique respondents participated. We found that there exists a strong medical need for and interest in the development of a center in the region, and participants reported that, if made available to them, they would make extensive and regular use of such a facility., Conclusions: We conclude that the establishment of a collaborative medical center specializing in the diagnosis and treatment of EDS, Hypermobility Spectrum Disorder, and related disorders in the Chicagoland area would greatly benefit patients by providing comprehensive care, alleviate the burden on overworked healthcare providers, and contribute to the sustainability of medical facilities., (© 2024. The Author(s).)

Introduction: Individuals with Ehlers-Danlos syndromes (EDS) often have complex and multi-faceted symptoms across the lifespan. Pain and the related symptoms of fatigue and sleep disorders are common. The objective of this qualitative study was to understand how participants manage their pain and related symptoms., Methods: The design was a qualitative thematic content analysis. Twenty-eight interviews were conducted to collect data from individuals who were participants in a prior quantitative longitudinal study. A semi-structured interview guide was designed to focus on and understand the trajectory of pain, sleep, fatigue, and general function. The interview continued with questions about coping mechanisms and obstacles to maintaining a sense of well-being., Results: Symptoms reported by participants were widespread and often interwoven. Pain was universal and often resulted in fatigue and disordered sleep which impacted physical function. Most participants reported that their symptoms worsened over time. Participants reported a wide range of effective interventions and most reported developing self-care strategies to adapt to their disabilities/limitations. Solutions included complementary interventions discovered when conventional medicine was unsuccessful. Very few relied on a "system" of health care and instead developed their own strategies to adapt to their disabilities/limitations., Discussion: EDS symptoms are often debilitating, and their progression is unknown. For most participants, symptoms worsened over the time. Even though participants in our study, by experience, were self-reliant, the importance of knowledgeable medical providers to help guide self-care should be emphasized., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Author CF declared that she was an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Schubart, Mills, Francomano and Stuckey-Peyrot.)

Patients with hypermobile Ehlers Danlos Syndrome often experience psychological distress resulting from the perceived hostility and disinterest of their clinicians. We conducted 26 in-depth interviews with patients to understand the origins of this trauma and how it could be addressed in practice. We found that the cumulative effects of numerous negative encounters lead patients to lose trust in their healthcare providers and the healthcare system, and to develop acute anxiety about returning to clinic to seek further care. We describe this as clinician-associated traumatization . Ultimately, our interviewees described the result of this traumatization as worse - but preventable - health outcomes., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to disclose.

Objective: Joint hypermobility in Ehlers-Danlos Syndromes (EDS) predisposes persons with EDS to frequent subluxations and dislocations, chronic arthralgia, and soft-tissue rheumatism. Epidemiologic trends of rheumatologic conditions among persons with EDS are lacking. Prescription claims databases can reflect underlying disease burdens by using medication claims as disease proxies. We examined the prevalence of prescription claims for commonly prescribed immunomodulator and antiinflammatory (IMD) drugs among persons with EDS compared with their matched control person, and hypothesized peripubertal increases among female persons with EDS., Methods: We compared the percentages of IMD drug prescription claims among 3,484 persons with EDS (ages 5-62 years) against their age-, sex-, state of residence-, and earliest claim date-matched control persons using 10 years (2005-2014) of private prescription claims data and a minimum 2-year enrollment inclusion criterion., Results: Our cohort comprised 70% adults and 74% female persons. At least 1 IMD medication was prescribed to 65.4% of persons with EDS compared with 47.4% of control persons. We observed 1.3 to 4.2 times higher odds (P < 0.0001) for 5 out of 6 IMD drug classes among persons with EDS compared with matched control persons, except for biologic agents (conditional odds ratio 1.3, 95% confidence interval 0.8-2.0). Peripubertal increases were observed for nonsteroidal antiinflammatory drugs, oral, and injectable steroids., Conclusions: To our knowledge, our study is the first to examine the full range of IMD drug prescription claim trends among persons with EDS. We believe our research findings can have notable diagnostic and management implications for EDS patients who present with multiple comorbidities and generally require a more granular assessment of their medical conditions., (© 2021 American College of Rheumatology.)

Mitochondrial dysfunction can be associated with a range of clinical manifestations. Here, we report a family with a complex phenotype including combinations of connective tissue, neurological, and metabolic symptoms that were passed on to all surviving children. Analysis of the maternally inherited mtDNA revealed a novel genotype encompassing the haplogroup J - defining mitochondrial DNA (mtDNA) ND5 m.13708G>A (A458T) variant arising on the mtDNA haplogroup H7A background, an extremely rare combination. Analysis of transmitochondrial cybrids with the 13708A-H7 mtDNA revealed a lower mitochondrial respiration, increased reactive oxygen species production (mROS), and dysregulation of connective tissue gene expression. The mitochondrial dysfunction was exacerbated by histamine, explaining why all eight surviving children inherited the dysfunctional histidine decarboxylase allele (W327X) from the father. Thus, certain combinations of common mtDNA variants can cause mitochondrial dysfunction, mitochondrial dysfunction can affect extracellular matrix gene expression, and histamine-activated mROS production can augment the severity of mitochondrial dysfunction. Most important, we have identified a previously unreported genetic cause of mitochondrial disorder arising from the incompatibility of common, nonpathogenic mtDNA variants.

Introduction Tethered cord syndrome (TCS) was first reported as a potential complication of Ehlers-Danlos Syndrome in 2009. However, there have been few publications on the subject since that time, and optimal treatment of TCS in the setting of the hypermobile Ehlers-Danlos Syndrome (hEDS) population remains unknown. The purpose of this study was to determine the safety and efficacy of surgical release of the filum terminale (FT) for the treatment of TCS in this patient population. Methods We performed a retrospective chart review of consecutive hEDS patients with TCS who were treated with surgical release after providing informed surgical consent over a 4.5-year period by a single neurosurgeon. Eighty-four patients were identified and asked to complete surveys with items regarding pre and postoperative symptoms, pain levels, and satisfaction. Results Thirty patients with a mean age of 30.8 ± 11.9 years, all female, were included. Low back pain was significantly improved across the entire cohort. For patients with both pre and postoperative data available, the distance they were able to walk also improved significantly. The majority of patients were "highly satisfied" with surgery (66%), followed by 21% "satisfied", 10% "neutral", and one patient who was "dissatisfied". One patient required repair of a dural leak one week postoperatively, and no other complications were noted. Conclusions Surgical release of the FT for TCS in patients with hEDS was safe and effective in this cohort. For most patients, there was a significant improvement in low back pain, urinary symptoms, and ability to ambulate distance. The majority of respondents reported subjective satisfaction with this operation. A further prospective study is warranted., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2022, Zingman et al.)

Hereditary alpha-tryptasemia (HαT) is an autosomal dominant (AD) genetic trait characterized by elevated basal serum tryptase ≥8 ng/mL, caused by increased α-tryptase-encoding TPSAB1 copy number. HαT affects 5% to 7% of Western populations and has been associated with joint hypermobility. Hypermobility disorders are likewise frequently AD, but genetic etiologies are often elusive. Genotyping of individuals with hypermobility spectrum disorder (n = 132), hypermobile Ehlers-Danlos syndrome (n = 78), or axial skeletal abnormalities with hypermobility (n = 56) was performed. Clinical features of individuals with and without HαT were compared. When analyzing our combined cohorts, dysphagia (p = 0.007) and retained primary dentition (p = 0.0003) were significantly associated with HαT, while positive associations with anaphylaxis (p = 0.07) and pruritus (P = 0.5) did not reach significance likely due to limited sample size. Overall, HαT prevalence is not increased in individuals with hypermobility disorders, rather linked to a unique endotype, demonstrating how HαT may modify clinical presentations of complex patients., Competing Interests: The authors declare no competing interests.

Alström Syndrome (ALMS) is an ultra-rare multisystem genetic disorder caused by autosomal recessive variants in the ALMS1 gene, which is located on chromosome 2p13. ALMS is a multisystem, progressive disease characterised by visual disturbance, hearing impairment, cardiomyopathy, childhood obesity, extreme insulin resistance, accelerated non-alcoholic fatty liver disease (NAFLD), renal dysfunction, respiratory disease, endocrine and urologic disorders. Clinical symptoms first appear in infancy with great variability in age of onset and severity. ALMS has an estimated incidence of 1 case per 1,000,000 live births and ethnically or geographically isolated populations have a higher-than-average frequency. The rarity and complexity of the syndrome and the lack of expertise can lead to delayed diagnosis, misdiagnosis and inadequate care. Multidisciplinary and multiprofessional teams of experts are essential for the management of patients with ALMS, as early diagnosis and intervention can slow the progression of multi-organ dysfunctions and improve patient quality of life.These guidelines are intended to define standard of care for patients suspected or diagnosed with ALMS of any age. All information contained in this document has originated from a systematic review of the literature and the experiences of the authors in their care of patients with ALMS. The Appraisal of Guidelines for Research & Evaluation (AGREE II) system was adopted for the development of the guidelines and for defining the related levels of evidence and strengths of recommendations.These guidelines are addressed to: a) specialist centres, other hospital-based medical teams and staffs involved with the care of ALMS patients, b) family physicians and other primary caregivers and c) patients and their families.

Ehlers-Danlos Syndromes (EDS) are a group of heritable disorders of connective tissue (HDCT) characterized by joint hypermobility, skin hyperextensibility, and tissue fragility. Orthostatic intolerance (OI) is highly prevalent in EDS however mechanisms linking OI to EDS remain poorly understood. We hypothesize that impaired blood pressure (BP) and heart rate control is associated with lower arterial stiffness in people with EDS. Orthostatic vital signs and arterial stiffness were assessed in a cohort of 60 people with EDS (49 female, 36 ± 16 years). Arterial elasticity was assessed by central and peripheral pulse wave velocity (PWV). Central PWV was lower in people with EDS compared to reference values in healthy subjects. In participants with EDS, central PWV was correlated to supine systolic BP (r = 0.387, p = 0.002), supine diastolic BP (r = 0.400, p = 0.002), and seated systolic BP (r = 0.399, p = 0.002). There were no significant correlations between PWV and changes in BP or heart rate with standing ( p > 0.05). Between EDS types, there were no differences in supine hemodynamics or PWV measures ( p > 0.05). These data demonstrate that increased arterial elasticity is associated with lower BP in people with EDS which may contribute to orthostatic symptoms and potentially provides a quantitative clinical measure for future genotype-phenotype investigations.

Background: People with the Ehlers-Danlos Syndromes (EDS), a group of heritable disorders of connective tissue, often report experiencing dental procedure pain despite local anesthetic (LA) use. Clinicians have been uncertain how to interpret this apparent LA resistance, as comparison of EDS and non-EDS patient experience is limited to anecdotal evidence and small case series. The primary goal of this hypothesis-generating study was to investigate the recalled adequacy of pain prevention with LA administered during dental procedures in a large cohort of people with and without EDS. A secondary exploratory aim asked people with EDS to recall comparative LA experiences., Methods: We administered an online survey through various social media platforms to people with EDS and their friends without EDS, asking about past dental procedures, LA exposures, and the adequacy of procedure pain prevention. Among EDS respondents who both received LA and recalled the specific LA used, we compared agent-specific pain prevention for lidocaine, procaine, bupivacaine, mepivacaine, and articaine., Results: Among the 980 EDS respondents who had undergone a dental procedure LA, 88% (n = 860) recalled inadequate pain prevention. Among 249 non EDS respondents only 33% (n = 83) recalled inadequate pain prevention (P < 0.001 compared to EDS respondents). The agent with the highest EDS-respondent reported success rate was articaine (30%), followed by bupivacaine (25%), and mepivacaine (22%)., Conclusions: EDS survey respondents reported nearly three times the rate of LA non-response compared to non-EDS respondents, suggesting that LAs were less effective in preventing their pain associated with routine office dental procedures., Competing Interests: DECLARATION OF INTEREST: The authors had no conflicts of interest to declare., (Copyright © 2019 Journal of Dental Anesthesia and Pain Medicine.)

Context: The Ehlers-Danlos Syndromes (EDSs) are a set of rare heritable disorders of connective tissue, characterized by defects in the structure and synthesis of extracellular matrix elements that lead to a myriad of problems including joint hypermobility and skin abnormalities. Because EDS affects multiple organ systems, defining clear boundaries and recognizing overlapping clinical features shared by disease phenotypes is challenging., Objectives: The objective of this study was to seek evidence of phenotypic subgroups of patients with distinctive symptom profiles and describe these resulting subgroups., Methods: Data were extracted from a repository assembled 2001-2013 by the National Institute on Aging Intramural Research Program. Agglomerative hierarchical clustering was used to form distinct subgroups of patients with respect to the domains of pain, physical and mental fatigue, daytime sleepiness, and nighttime sleep. Domains were selected based on literature review, clinician expertise, and guidance from patient advisors., Results: One hundred seventy-five patients met all inclusion criteria. Three subgroups were identified. The Pain Dominant subgroup (39 patients) had the highest mean pain values, but lowest mean values of other symptoms. The High Symptom Burden subgroup (71 patients) had high mean values in all domains. The Mental Fatigue subgroup (65 patients) had a high mean value for mental fatigue and daytime sleepiness, but a lower mean value for pain., Conclusion: The subgroups aligned with clinical observation of the heterogeneous nature of EDS, with overlapping symptoms between subtypes and a wide divergence in degree of symptoms within subtypes. This exploratory study helps characterize the various phenotypes and comorbidities of patients with EDS., (Copyright © 2019 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.)

AEBP1 encodes the aortic carboxypeptidase-like protein (ACLP) that associates with collagens in the extracellular matrix (ECM) and has several roles in development, tissue repair, and fibrosis. ACLP is expressed in bone, the vasculature, and dermal tissues and is involved in fibroblast proliferation and mesenchymal stem cell differentiation into collagen-producing cells. Aebp1 -/- mice have abnormal, delayed wound repair correlating with defects in fibroblast proliferation. In this study, we describe four individuals from three unrelated families that presented with a unique constellation of clinical findings including joint laxity, redundant and hyperextensible skin, poor wound healing with abnormal scarring, osteoporosis, and other features reminiscent of Ehlers-Danlos syndrome (EDS). Analysis of skin biopsies revealed decreased dermal collagen with abnormal collagen fibrils that were ragged in appearance. Exome sequencing revealed compound heterozygous variants in AEBP1 (c.1470delC [p.Asn490&#95;Met495delins(40)] and c.1743C>A [p.Cys581 ∗ ]) in the first individual, a homozygous variant (c.1320&#95;1326del [p.Arg440Serfs ∗ 3]) in the second individual, and a homozygous splice site variant (c.1630+1G>A) in two siblings from the third family. We show that ACLP enhances collagen polymerization and binds to several fibrillar collagens via its discoidin domain. These studies support the conclusion that bi-allelic pathogenic variants in AEBP1 are the cause of this autosomal-recessive EDS subtype., (Copyright © 2018 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Objective: The chondron is a basic unit of articular cartilage that includes the chondrocyte and its pericellular matrix (PCM). This current study was designed to investigate the effects of the chondron PCM on the gene expression profile of chondrocytes., Design: Chondrons and chondrocytes were enzymatically isolated from human articular cartilage, and maintained in pellet culture. Pellets of chondrons or chondrocytes were collected at days 1, 3 and 5 for cDNA microarray analysis., Results: In comparison with chondrocytes alone, chondrons had 258 genes, in a broad range of functional categories, either up- or downregulated at the three time points tested. At day 1, 26 genes were significantly upregulated in chondrons and four downregulated in comparison to chondrocytes. At day 3, the number of upregulated chondron genes was 97 and the number downregulated was 43. By day 5, there were more downregulated genes (56) than upregulated genes (32) in chondrons. Upregulation of a group of heat shock proteins (HSPA1A, HSPA2 and HSPA8) in chondrons was validated by real time reverse transcription polymerase chain reaction (RT-PCR). Genes related to chondrocyte hypertrophy and dedifferentiation such as SSP1 and DCN were downregulated in chondrons as compared to the expression in chondrocytes., Conclusion: The presence of the PCM in chondrons has a profound influence on chondrocyte gene expression. Upregulation of the heat shock protein 70 may contribute to the robustness and active matrix production of chondrons. The intact PCM may further stabilize the phenotype of chondrocytes within chondrons.

Cartilage engineering is a strategic experimental goal for the treatment of multiple joint diseases. Based on the process of embryonic chondrogenesis, we hypothesized that cartilage could be engineered by condensing chondrocytes in pellet culture and, in the present study, examined the quality of regenerated cartilage in direct comparison with native cartilage. Chondrocytes isolated from the sterna of chick embryos were cultured in pellets (4 x 10(6) cells per pellet) for 2 weeks. Cartilage explants from the same source were cultured as controls. After 2 weeks, the regenerated cartilage from pellet culture had a disc shape and was on average 9 mm at the longest diameter. The chondrocyte phenotype was stabilized in pellet culture as shown by the synthesis of type II collagen and aggrecan, which was the same intensity as in the explant after 7 days in culture. During culture, chondrocytes also continuously synthesized type IX collagen. Type X collagen was negatively stained in both pellets and explants. Except for fibril orientation, collagen fibril diameter and density in the engineered cartilage were comparable with the native cartilage. In conclusion, hyaline cartilage engineered by chondrocytes in pellet culture, without the transformation of cell phenotypes and scaffold materials, shares similarities with native cartilage in cellular distribution, matrix composition and density, and ultrastructure.

Background: Chondrodystrophic myotonia or Schwartz-Jampel syndrome is a rare genetic disorder characterized by myotonia and skeletal dysplasia. It may be progressive in nature. Recently, the gene responsible for Schwartz-Jampel syndrome has been found and the defective protein it encodes leads to abnormal cartilage development and anomalous neuromuscular activity., Case Presentation: We report the clinical findings and the management of an 8-year-old boy with this disorder. The molecular findings confirm that the patient is a compound heterozygote with a different splicing mutation in each Perlecan allele. This resulted in a significant reduction in the production of the encoded normal protein., Conclusion: We discuss the multi-disciplinary management of Schwartz-Jampel syndrome that will facilitate optimal care and timely intervention of patients with this disorder.

Purpose: To evaluate a cohort of clinically diagnosed Stickler patients in which the causative mutation has been identified, determine the prevalence of clinical features in this group as a whole and as a function of age, and look for genotype/phenotype correlations., Methods: Review of medical records, clinical evaluations, and mutational analyses of clinically diagnosed Stickler patients., Results: Patients with seven defined mutations had similar phenotypes, though both inter- and intrafamilial variability were apparent and extensive. The prevalence of certain clinical features was a function of age., Conclusion: Although the molecular determination of a mutation can predict the occurrence of Stickler syndrome, the variability observed in the families described here makes it difficult to predict the severity of the phenotype on the basis of genotype.

Purpose: To determine the prevalence of proximal aortic abnormalities in patients with Ehlers-Danlos syndrome (EDS)., Methods: In a prospective cohort study, aortic measurements by two-dimensional echocardiography were performed on consecutive EDS patients., Results: Twenty-eight percent (20 of 71) had aortic root dilation (ARD) (> +2 SD above population based norms). Fourteen of 42 individuals with the classical form of EDS (types I/II) and 6 of 29 individuals with the hypermobile form (type III) had ARD, with no gender differences., Conclusion: ARD is a common finding in EDS. Longitudinal studies are indicated to determine progression of ARD and its clinical significance.

Perlecan, a large heparan sulfate proteoglycan, is a component of the basement membrane and other extracellular matrices and has been implicated in multiple biological functions. Mutations in the perlecan gene (HSPG2) cause two classes of skeletal disorders: the relatively mild Schwartz-Jampel syndrome (SJS) and severe neonatal lethal dyssegmental dysplasia, Silverman-Handmaker type (DDSH). SJS is an autosomal recessive skeletal dysplasia characterized by varying degrees of myotonia and chondrodysplasia, and patients with SJS survive. The molecular mechanism underlying the chondrodystrophic myotonia phenotype of SJS is unknown. In the present report, we identify five different mutations that resulted in various forms of perlecan in three unrelated patients with SJS. Heterozygous mutations in two patients with SJS either produced truncated perlecan that lacked domain V or significantly reduced levels of wild-type perlecan. The third patient had a homozygous 7-kb deletion that resulted in reduced amounts of nearly full-length perlecan. Unlike DDSH, the SJS mutations result in different forms of perlecan in reduced levels that are secreted to the extracellular matrix and are likely partially functional. These findings suggest that perlecan has an important role in neuromuscular function and cartilage formation, and they define the molecular basis involved in the difference in the phenotypic severity between DDSH and SJS.

Human bone marrow stromal cells (HBMSC) are pluripotent cells with the potential to differentiate into osteoblasts, chondrocytes, myelosupportive stroma, and marrow adipocytes. We used high-throughput DNA sequencing analysis to generate 4258 single-pass sequencing reactions (known as expressed sequence tags, or ESTs) obtained from the 5' (97) and 3' (4161) ends of human cDNA clones from a HBMSC cDNA library. Our goal was to obtain tag sequences from the maximum number of possible genes and to deposit them in the publicly accessible database for ESTs (dbEST of the National Center for Biotechnology Information). Comparisons of our EST sequencing data with nonredundant human mRNA and protein databases showed that the ESTs represent 1860 gene clusters. The EST sequencing data analysis showed 60 novel genes found only in this cDNA library after BLAST analysis against 3.0 million ESTs in NCBI's dbEST database. The BLAST search also showed the identified ESTs that have close homology to known genes, which suggests that these may be newly recognized members of known gene families. The gene expression profile of this cell type is revealed by analyzing both the frequency with which a message is encountered and the functional categorization of expressed sequences. Comparing an EST sequence with the human genomic sequence database enables assignment of an EST to a specific chromosomal region (a process called digital gene localization) and often enables immediate partial determination of intron/exon boundaries within the genomic structure. It is expected that high-throughput EST sequencing and data mining analysis will greatly promote our understanding of gene expression in these cells and of growth and development of the skeleton.

We characterize the cDNA and genomic structure of NSBP1, and demonstrate that it is a nuclear protein and the homologue of mouse Nsbp1, which is known to encode a nucleosomal binding and transcriptional activating protein related to the HMG-14/-17 chromosomal proteins. The encoded NSBP1 protein has 86% amino acid similarity to Nsbp1, including identity in nucleosomal binding domains of the HMG-14/-17 proteins. Our radiation hybrid data localize NSBP1 and Nsbp1 to homologous regions of chromosome X, with NSBP1 in Xq13.3 between DXS983 and DXS995 and Nsbp1 in the interval DXMit65 and DXMit39. Although Nsbp1 produces one mRNA transcript, NSBP1 produces three transcripts with alternate polyadenylated sites. The 3' untranslated region (UTR) of NSPB1 mRNA also contains several AU-rich elements (AREs), which are associated with rapid mRNA turnover. Northern analysis of NSBP1/Nsbp1 shows differences in transcript abundance among adult and fetal tissues, with predominant expression in liver, kidney, trabecular bone, and bone marrow stromal cells. However, a reverse transcriptase-PCR analysis shows nearly ubiquitous expression of the three NSBP1 transcripts in all tissues examined, although the abundance of each transcript was not quantified. NSBP1 is encoded by six exons and has exon-intron boundaries identical to the HMG-14/-17 genes. The last exon and the 3' UTR of NSBP1 contain retrotransposon sequences of HAL1, HERV-H, and L1MB7, suggesting that these retrotransposons were involved in the origin of NSPB1 from an ancestral-like HMG-14/-17 gene. The similarities among NSBP1, Nsbp1, and the HMG-14/-17 proteins suggest that NSBP1 may function as a nucleosomal binding and transcriptional activating element. Further, the AREs in the 3' UTR of NSPB1 suggest that alternate poly(A) site selection may mediate the mRNA stability of this gene.

The fibroblast growth factor-receptor 3 (FGFR3) Lys650 codon is located within a critical region of the tyrosine kinase-domain activation loop. Two missense mutations in this codon are known to result in strong constitutive activation of the FGFR3 tyrosine kinase and cause three different skeletal dysplasia syndromes-thanatophoric dysplasia type II (TD2) (A1948G [Lys650Glu]) and SADDAN (severe achondroplasia with developmental delay and acanthosis nigricans) syndrome and thanatophoric dysplasia type I (TD1) (both due to A1949T [Lys650Met]). Other mutations within the FGFR3 tyrosine kinase domain (e.g., C1620A or C1620G [both resulting in Asn540Lys]) are known to cause hypochondroplasia, a relatively common but milder skeletal dysplasia. In 90 individuals with suspected clinical diagnoses of hypochondroplasia who do not have Asn540Lys mutations, we screened for mutations, in FGFR3 exon 15, that would disrupt a unique BbsI restriction site that includes the Lys650 codon. We report here the discovery of three novel mutations (G1950T and G1950C [both resulting in Lys650Asn] and A1948C [Lys650Gln]) occurring in six individuals from five families. Several physical and radiological features of these individuals were significantly milder than those in individuals with the Asn540Lys mutations. The Lys650Asn/Gln mutations result in constitutive activation of the FGFR3 tyrosine kinase but to a lesser degree than that observed with the Lys540Glu and Lys650Met mutations. These results demonstrate that different amino acid substitutions at the FGFR3 Lys650 codon can result in several different skeletal dysplasia phenotypes.

Systematic organization of documented data coupled with ready accessibility is of great value to research. Catalogs and databases are created specifically to meet this purpose. The Skeletal Gene Database evolves as part of the Skeletal Genome Anatomy Project (SGAP), an ongoing multi-institute collaborative effort, to study the functional genome of bone and other skeletal tissues. The primary objective of the Skeletal Gene Database is to create a contemporary list of skeletal-related genes, offering the following information for each gene: gene name, protein name, cellular function, disease(s) caused by mutation of the corresponding gene, chromosomal location, LocusLink number, gene size, exon/intron numbers, messenger RNA (mRNA) coding region size, protein size/molecular weight, Online Mendelian Inheritance in Man (OMIM) number of the gene, UniGene assignment, and PubMed reference. The database includes genes already known and published in the literature as well as novel genes not yet characterized but known to be expressed in skeletal tissue. It will be posted on the web for easy access and swift referencing. The data will be updated in tempo with current and future research, thereby providing an invaluable service to the scientific community interested in obtaining information on bone-related genes.

The nemaline myopathies are characterized by weakness and eosinophilic, rodlike (nemaline) inclusions in muscle fibers. Amish nemaline myopathy is a form of nemaline myopathy common among the Old Order Amish. In the first months of life, affected infants have tremors with hypotonia and mild contractures of the shoulders and hips. Progressive worsening of the proximal contractures, weakness, and a pectus carinatum deformity develop before the children die of respiratory insufficiency, usually in the second year. The disorder has an incidence of approximately 1 in 500 among the Amish, and it is inherited in an autosomal recessive pattern. Using a genealogy database, automated pedigree software, and linkage analysis of DNA samples from four sibships, we identified an approximately 2-cM interval on chromosome 19q13.4 that was homozygous in all affected individuals. The gene for the sarcomeric thin-filament protein, slow skeletal muscle troponin T (TNNT1), maps to this interval and was sequenced. We identified a stop codon in exon 11, predicted to truncate the protein at amino acid 179, which segregates with the disease. We conclude that Amish nemaline myopathy is a distinct, heritable, myopathic disorder caused by a mutation in TNNT1.

Purpose: To compare the Berlin and Ghent diagnostic criteria for Marfan syndrome and evaluate the utility of screening for dural ectasia in the diagnosis of Marfan syndrome., Methods: Review of clinical and radiographic data on 73 patients evaluated for Marfan syndrome at the National Institutes of Health., Results: Nineteen percent of patients diagnosed under the Berlin criteria failed to meet the Ghent standard. Dural ectasia was the second most common major diagnostic manifestation, and screening for dural ectasia established the diagnosis of Marfan syndrome in 23% of patients under the Ghent criteria., Conclusions: Some patients are appropriately excluded from the diagnosis of Marfan syndrome by the Ghent criteria. Determination of dural ectasia is valuable in the diagnosis of Marfan syndrome.

Achondroplasia, the most common form of short-limbed dwarfism in humans, occurs between 1 in 15,000 and 40,000 live births. More than 90% of cases are sporadic and there is, on average, an increased paternal age at the time of conception of affected individuals. More then 97% of persons with achondroplasia have a Gly380Arg mutation in the transmembrane domain of the fibroblast growth factor receptor (FGFR) 3 gene. Mutations in the FGFR3 gene also result in hypochondroplasia, the lethal thanatophoric dysplasias, the recently described SADDAN (severe achondroplasia with developmental delay and acanthosis nigricans) dysplasia, and two craniosynostosis disorders: Muenke coronal craniosynostosis and Crouzon syndrome with acanthosis nigricans. Recent evidence suggests that the phenotypic differences may be due to specific alleles with varying degrees of ligand-independent activation, allowing the receptor to be constitutively active. Since the Gly380Arg achondroplasia mutation was recognized, similar observations regarding the conserved nature of FGFR mutations and resulting phenotype have been made regarding other skeletal phenotypes, including hypochondroplasia, thanatophoric dysplasia, and Muenke coronal craniosynostosis. These specific genotype-phenotype correlations in the FGFR disorders seem to be unprecedented in the study of human disease. The explanation for this high degree of mutability at specific bases remains an intriguing question.

Talin is a high-molecular-weight cytoskeletal protein, localized at cell-extracellular matrix associations known as focal contacts. In these regions, talin is thought to link integrin receptors to the actin cytoskeleton. Talin plays a key role in the assembly of actin filaments and in spreading and migration of various cell types. Talin proteins are found in a wide variety of organisms, from slime molds to humans. The human Talin (HGMW-approved symbol TLN) gene was previously mapped to chromosome 9p, but little was known of its sequence and genomic structure. To characterize human TLN further, we have isolated a single bacterial artificial chromosome clone, harboring the entire gene. The gene extends over more than 23 kb and consists of 57 exons. We have localized TLN to human chromosome band 9p13 by both fluorescence in situ hybridization and radiation hybrid mapping. Northern blot analysis detected TLN expression in various human tissues, including leukocytes, lung, placenta, liver, kidney, spleen, thymus, colon, skeletal muscle, and heart. Based on its chromosomal location, expression pattern, and protein function, we considered TLN as a candidate gene for cartilage-hair hypoplasia (CHH), an autosomal recessive metaphyseal chondrodysplasia, previously mapped to 9p13. We sequenced the entire TLN coding sequence in several CHH patients, but no functional mutations were detected., (Copyright 1999 Academic Press.)

We have identified a novel fibroblast growth factor receptor 3 (FGFR3) missense mutation in four unrelated individuals with skeletal dysplasia that approaches the severity observed in thanatophoric dysplasia type I (TD1). However, three of the four individuals developed extensive areas of acanthosis nigricans beginning in early childhood, suffer from severe neurological impairments, and have survived past infancy without prolonged life-support measures. The FGFR3 mutation (A1949T: Lys650Met) occurs at the nucleotide adjacent to the TD type II (TD2) mutation (A1948G: Lys650Glu) and results in a different amino acid substitution at a highly conserved codon in the kinase domain activation loop. Transient transfection studies with FGFR3 mutant constructs show that the Lys650Met mutation causes a dramatic increase in constitutive receptor kinase activity, approximately three times greater than that observed with the Lys650Glu mutation. We refer to the phenotype caused by the Lys650Met mutation as "severe achondroplasia with developmental delay and acanthosis nigricans" (SADDAN) because it differs significantly from the phenotypes of other known FGFR3 mutations.

Nail-patella syndrome (NPS), a pleiotropic disorder exhibiting autosomal dominant inheritance, has been studied for >100 years. Recent evidence shows that NPS is the result of mutations in the LIM-homeodomain gene LMX1B. To determine whether specific LMX1B mutations are associated with different aspects of the NPS phenotype, we screened a cohort of 41 NPS families for LMX1B mutations. A total of 25 mutations were identified in 37 families. The nature of the mutations supports the hypothesis that NPS is the result of haploinsufficiency for LMX1B. There was no evidence of correlation between aspects of the NPS phenotype and specific mutations.

Mutations in the FBN1 gene, which encodes fibrillin-1, cause Marfan syndrome (MFS) and have been associated with a wide range of milder, overlap phenotypes. The factors that modulate phenotypic severity, both between and within families, remain to be determined. This study examines the relationship between the FBN1 genotype and phenotype in families with extremely mild phenotypes and in those that show striking clinical variation among apparently affected individuals. In one family, clinically similar but etiologically distinct disorders are segregating independently. In another, somatic mosaicism for a mutant FBN1 allele is associated with subdiagnostic manifestations, whereas germ-line transmission of the identical mutation causes severe and rapidly progressive disease. A third family cosegregates mild mitral valve prolapse syndrome with a mutation in FBN1 that can be functionally distinguished from those associated with the classic MFS phenotype. These data have immediate relevance for the diagnostic and prognostic counseling of patients and their family members.

More than 97% of achondroplasia cases are caused by one of two mutations (G1138A and G1138C) in the fibroblast growth factor receptor 3 (FGFR3) gene, which results in a specific amino acid substitution, G380R. Sporadic cases of achondroplasia have been associated with advanced paternal age, suggesting that these mutations occur preferentially during spermatogenesis. We have determined the parental origin of the achondroplasia mutation in 40 sporadic cases. Three distinct 1-bp polymorphisms were identified in the FGFR3 gene, within close proximity to the achondroplasia mutation site. Ninety-nine families, each with a sporadic case of achondroplasia in a child, were analyzed in this study. In this population, the achondroplasia mutation occurred on the paternal chromosome in all 40 cases in which parental origin was unambiguous. This observation is consistent with the clinical observation of advanced paternal age resulting in new cases of achondroplasia and suggests that factors influencing DNA replication or repair during spermatogenesis, but not during oogenesis, may predispose to the occurrence of the G1138 FGFR3 mutations.

This paper describes PedHunter, a software package that facilitates creation and verification of pedigrees within large genealogies. A frequent problem in medical genetics is to connect distant relatives with a pedigree. PedHunter uses methods from graph theory to solve two versions of the pedigree connection problem for genealogies as well as other pedigree analysis problems. The pedigrees are produced by PedHunter as files in LINKAGE format ready for linkage analysis. PedHunter uses a relational database of genealogy data, with tables in specified format, for all calculations. The functionality and utility of PedHunter are illustrated by examples using the Amish Genealogy Database (AGDB), which was created for the Old Order Amish community of Lancaster County, Pennsylvania.

The underlying basis of many forms of syndromic craniosynostosis has been defined on a molecular level. However, many patients with familial or sporadic craniosynostosis do not have the classical findings of those craniosynostosis syndromes. Here we present 61 individuals from 20 unrelated families where coronal synostosis is due to an amino acid substitution (Pro250Arg) that results from a single point mutation in the fibroblast growth factor receptor 3 gene on chromosome 4p. In this instance, a new clinical syndrome is being defined on the basis of the molecular finding. In addition to the skull findings, some patients had abnormalities on radiographs of hands and feet, including thimble-like middle phalanges, coned epiphyses, and carpal and tarsal fusions. Brachydactyly was seen in some cases; none had clinically significant syndactyly or deviation of the great toe. Sensorineural hearing loss was present in some, and developmental delay was seen in a minority. While the radiological findings of hands and feet can be very helpful in diagnosing this syndrome, it is not in all cases clearly distinguishable on a clinical basis from other craniosynostosis syndromes. Therefore, this mutation should be tested for in patients with coronal synostosis.

Nail-patella syndrome (NPS), or onychoosteodysplasia, is an autosomal dominant, pleiotropic disorder characterized by nail dysplasia, absent or hypoplastic patellae, iliac horns, and nephropathy. Previous studies have demonstrated linkage of the nail-patella locus to the ABO and adenylate kinase loci on human chromosome 9q34. As a first step toward isolating the NPS gene, we present linkage analysis with 13 polymorphic markers in five families with a total of 69 affected persons. Two-point linkage analysis with the program MLINK showed tight linkage of NPS and the anonymous markers D9S112 (LOD = 27.0; theta = .00) and D9S315 (LOD = 22.0; theta = .00). Informative recombination events place the NPS locus within a 1-2-cM interval between D9S60 and the adenylate kinase gene (AK1).

Brachydactyly type C is an autosomal dominant disorder characterized by abnormal segmentation of the index and middle fingers segregating with a high degree of variable expression in members of the same family. We have followed up and studied members of the large kindred segregating with the brachydactyly type C phenotype described by Virgil Haws in 1963, and using genetic linkage analysis, we localized the susceptibility gene to human chromosome 12q24.

Pycnodysostosis (MIM 265800) is a rare, autosomal recessive skeletal dysplasia characterized by short stature, wide cranial sutures, and increased bone density and fragility. Linkage analysis localized the disease gene to human chromosome 1q21, and subsequently the genetic interval was narrowed to between markers D1S2612 and D1S2345. Expressed sequence tagged markers corresponding to cathepsin K, a cysteine protease highly expressed in osteoclasts and thought to be important in bone resorption, were mapped previously in the candidate region. We have identified a cytosine to thymidine transition at nucleotide 862 (GenBank accession no. S79895) of the cathepsin K coding sequence in the DNA of an affected individual from a large, consanguinous Mexican family. This mutation results in an arginine to STOP alteration at amino acid 241, predicting premature termination of cathepsin K mRNA translation. All affected individuals in this family were homozygous for the mutation, suggesting that this alteration may lead to pycnodysostosis. Recognition of the role of cathepsin K in the etiology of pycnodysostosis should provide insights into the pathogenesis and treatment of other disorders of bone remodeling, including osteoporosis.

Ellis van Creveld syndrome (EVC) is an autosomal recessive disorder which has previously been mapped to human chromosome 4p16.1. This disorder is characterized by disproportionate dwarfism, polydactyly, cleft palate, natal teeth, and congenital heart disease. The MSX1 homeobox gene also maps to the 4p16.1 region. Msx gene transcripts in the mouse embryo are known to be involved in pattern formation of the developing limb bud and craniofacial bones. Thus, on the basis of both map location and known gene function, MSX1 was an excellent candidate as the causative gene for EVC. Nonetheless, direct DNA sequencing of both exons of the MSX1 gene in five affected individuals segregating with the EVC phenotype, as well as those of two obligate carriers, revealed no mutations in the coding region of the gene.

Ellis-van Creveld syndrome (EVC) is an autosomal recessive disorder characterized by disproportionate dwarfism, polydactyly, and congenital heart disease. This rare disorder is found with increased frequency among the Old Order Amish community in Lancaster County, Pennsylvania. We have used linkage analysis to localize the gene responsible for the EVC phenotype in nine interrelated Amish pedigrees and three unrelated families from Mexico, Ecuador, and Brazil. We now report the linkage for the Ellis-van Creveld syndrome gene to markers on the distal short arm of human chromosome 4, with Zmax = 6.91 at theta = 0.02 for marker HOX7, in a region proximal to the FGFR3 gene responsible for the achondroplasia phenotype.

The recent explosion in the number of identified genes involved in the human skeletal dysplasias has dramatically advanced this particular field. While linkage efforts are mapping hereditary disorders of the skeleton at an ever accelerating pace, progress in the Human Genome Project is providing tools for rapid gene discovery after the map location is known. Emerging themes in the molecular analysis of the skeletal dysplasias include the identification of allelic series of disorders and the existence of mutational and genetic heterogeneity in many of these conditions. Allelic series include those conditions caused by mutations in the genes encoding type II collagen (COL2A1), cartilage oligomeric matrix protein (COMP), fibroblast growth factor receptor 3 (FGFR3) and the diastrophic dysplasia sulfate transporter (DTDST). The recognition of these phenomena has initiated the analysis of the relationship between disease phenotype and gene.

Mutations in the gene encoding fibrillin-1 (FBN1), a component of the extracellular microfibril, cause the Marfan syndrome (MFS). This statement is supported by the observations that the classic Marfan phenotype cosegregates with intragenic and/or flanking marker alleles in all families tested and that a significant number of FBN1 mutations have been identified in affected individuals. We have now devised a method to screen the entire coding sequence and flanking splice junctions of FBN1. On completion for a panel of nine probands with classic MFS, six new mutations were identified that accounted for disease in seven (78%) of nine patients. Nine additional new mutations have been characterized in the early stages of a larger screening project. These 15 mutations were equally distributed throughout the gene and, with one exception, were specific to single families. One-third of mutations created premature termination codons, and 6 of 15 substituted residues with putative significance for calcium binding to epidermal growth factor (EGF)-like domains. Mutations causing severe and rapidly progressive disease that presents in the neonatal period can occur in a larger region of the gene than previously demonstrated, and the nature of the mutation is as important a determinant as its location, in predisposing to this phenotype.

Proximal symphalangism, or Cushing symphalangism (MIM 185800), is an autosomal dominant disorder characterized by ankylosis of the proximal interphalangeal joints. Conductive deafness and reduced flexibility of the ankles have also been observed in affected individuals. We have used polymorphic markers throughout the genome to perform genetic linkage analysis in subsequent generations of the family originally described by Harvey Cushing. We have established linkage for this disorder to markers on chromosome 17 (17q21-q22), with Zmax = 6.98 at theta = 0.05 with marker D17S790.

COL5A1, the gene for the alpha 1 chain of type V collagen, has been considered a candidate gene for certain diseases based on chromosomal location and/or disease phenotype. We have employed 3'-untranslated region RFLPs to exclude COL5A1 as a candidate gene in families with tuberous sclerosis 1, Ehlers-Danlos syndrome type II, and nail-patella syndrome. In addition, we describe a polymorphic simple sequence repeat (SSR) within a COL5A1 intron. This SSR is used to exclude COL5A1 as a candidate gene in hereditary hemorrhagic telangiectasia (Osler-Rendu-Weber disease) and to add COL5A1 to the existing map of "index" markers of chromosome 9 by evaluation of the COL5A1 locus on the CEPH 40-family reference pedigree set. This genetic mapping places COL5A1 between markers D9S66 and D9S67.

Genomic DNA from 154 unrelated individuals with achondroplasia was evaluated for mutations in the fibroblast growth factor receptor 3 (FGFR3) transmembrane domain. All but one, an atypical case, were found to have a glycine-to-arginine substitution at codon 380. Of these, 150 had a G-to-A transition at nt 1138, and 3 had a G-to-C transversion at this same position. On the basis of estimates of the prevalence of achondroplasia, the mutation rate at the FGFR3 1138 guanosine nucleotide is two to three orders of magnitude higher than that previously reported for tranversions and transitions in CpG dinucleotides. To date, this represents the most mutable single nucleotide reported in the human genome. The homogeneity of mutations in achondroplasia is unprecedented for an autosomal dominant disorder and may explain the relative lack of heterogeneity in the achondroplasia phenotype.

We recently assigned the gene for an autosomal recessive skeletal dysplasia, cartilage-hair hypoplasia (CHH), to 9p21-p13 in Finnish and Amish families. An association was observed between CHH and alleles at D9S163 in both family series, suggesting that these loci are in linkage disequilibrium and close to each other. Here we extended these studies by exploiting the linkage-disequilibrium information that can be obtained from families with a single affected child, and we studied 66 Finnish CHH families with seven microsatellite markers. The analysis based on the Luria and Delbrück (1943) method and adapted to the study of human founder populations suggests that the distance between CHH and D9S163 is approximately 0.3 cM. An eight-point linkage analysis modified to take advantage of all possible information in 15 Finnish and 17 Amish families was capable of narrowing the likely location of CHH to within an interval of 1.7 cM on a male map. The peak lod score of 54.92 was attained 0.03 and 0.1 cM proximal to D9S163 on the male and female maps, respectively. These results confirm the power of genetic resolution, that lies in the study of linkage disequilibrium in well-defined founder populations with one major ancestral disease mutation.

We recently assigned the gene for cartilage-hair hypoplasia (CHH) to chromosome 9 in Finnish families. Here we have extended and refined our previous linkage analyses by studying 22 Amish and 15 Finnish CHH families and by testing additional markers. The CHH gene maps to 9p in both series and shows no evidence of heterogeneity either within or between the populations. CHH is very closely linked to marker locus D9S163, with no recombinations observed and a combined maximum multipoint lod score of 26.30 for a location at D9S163. Although the odds against a location of the CHH gene between two more distal marker loci, D9S52 and D9S165, are only 48:1, the evidence provided by an observed recombination between the CHH locus and D9S165 and haplotype data at D9S165 and D9S163 in the Amish families allow this interval to be excluded as the location of CHH. We observed strong allelic association between CHH and D9S163 in both Amish and Finnish families, confirming the likely location of the CHH gene very close to this marker. Haplotype analysis of D9S163 and D9S165 in the Amish families suggests that only one mutation accounts for most CHH cases among them, as was expected and as is the case in Finland. Our data do not support the previously suggested hypothesis of a reduced penetrance as an explanation for the deficiency of affected children in the Amish families. We conclude that CHH is a single disease entity in the Amish and Finnish families and that the CHH gene is very close to D9S163 in 9p21-p13.