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Cavernous cerebral malformations (CCM) are vascular malformations of the brain and spinal cord. CCM affect up to 0.5% of the general population, predisposing to headaches, seizures, cerebral hemorrhage and focal neurological deficit. CCM may be familial or sporadic. Familial forms have autosomal dominant inheritance. This Utility Gene Test was prepared on the basis of an analysis of the literature and existing diagnostic protocols. It is useful for confirming diagnosis, as well as for differential diagnosis, couple risk assessment and access to clinical trials.

Abstract Background HOXB1 plays a major role in brainstem morphogenesis and could partly determine the cranial circumference in conjunction with HOXA1. In our sample, HOXA1 alleles significantly influence head growth rates both in autistic patients and in population controls. An initial report, suggesting that HOXB1 could confer autism vulnerability in interaction with HOXA1, was not confirmed by five small association studies. Methods Our sample includes 269 autistic individuals, belonging to 219 simplex and 28 multiplex families. A mutational analysis of the two exons and flanking intronic sequences of the HOXB1 gene was carried out in 84 autistic patients by denaturing high performance liquid chromatography, followed by DNA sequencing. Identified rare variants were then searched by a restriction analysis in 236 autistic patients and 325-345 controls. Case-control and family-based association studies were performed on two common variants in 169 Italian patients versus 184 Italian controls and in 247 trios. Results We identified three common polymorphisms, rs72338773 [c.82insACAGCGCCC (INS/nINS)], rs12939811 [c.309A>T (Q103H)], and rs7207109 [c.450G>A (A150A)] and three rare variants, namely IVS1+63G>A, rs35115415 [c.702G>A (V234V)] and c.872_873delinsAA (S291N). SNPs rs72338773 and rs12939811 were not associated with autism, using either a case-control (alleles, exact P = 0.13) or a family-based design [transmission/disequilibrium test (TDT)χ2 = 1.774, P = 0.183]. The rare variants, all inherited from one of the parents, were present in two Italian and in two Caucasian-American families. Autistic probands in two families surprisingly inherited a distinct rare variant from each parent. The IVS1+63A allele was present in 3/690 control chromosomes, whereas rare alleles at rs35115415 and c.872_873delinsAA (S291N) were not found in 662 and 650 control chromosomes, respectively. The INS-T309 allele influenced head size, but its effect appears more modest and shows no interaction with HOXA1 alleles. The INS-T309 allele is also associated with more severe stereotypic behaviours, according to ADI-R scores (N = 60 patients, P < 0.01). Conclusions HOXB1 mutations do not represent a common cause of autism, nor do HOXB1 common variants play important roles in autism vulnerability. HOXB1 provides minor, albeit detectable contributions to head circumference in autistic patients, with HOXA1 displaying more prominent effects. HOXB1 variants may modulate the clinical phenotype, especially in the area of stereotypic behaviours.

Cerebral cavernous malformation (CCM) is a vascular malformation of the central nervous system which may occur sporadically or segregate within families due to heterozygous variants in KRIT1/CCM1, MGC4607/CCM2 or PDCD10/CCM3. Intronic variants are not uncommon in familial CCM, but their clinical interpretation is often hampered by insufficient data supporting in silico predictions. Here, the mRNA analysis for two intronic unpublished variants (KRIT1 c.1147-7 T > G and PDCD10 c.395 + 2 T > G) and three previously published variants in KRIT1 but without data supporting their effects was carried out. This study demonstrated that all variants can induce a frameshift with the lack of residues located in the C-terminal regions and involved in protein-protein complex formation, which is essential for vascular homeostasis. These results support the introduction of mRNA analysis in the diagnostic pathway of familial CCM and expand the knowledge of abnormal splicing patterning in this disorder., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background and Aim: Infertility affects ~20% of the couples in the world. Assisted reproductive technologies (ARTs) are currently the most common treatment option for infertility. Nevertheless, ARTs may be associated with complications for mothers and/or offspring. Natural procreative technology (NaProTechnology) is a natural treatment which minimizes these risks by seeking to identify the causes of infertility to enable better treatments. This narrative review summarizes the complications related to ARTs and clarifies how the NaProTechnology approach can help ARTs to achieve better results or be used in alternative to ARTs., Methods: Data in the literature indicate that NaProTechnology is a natural approach for treating infertility., Results: The percentage of live births obtained by NaProTechnology is similar to that of ARTs., Conclusions: An extensive search for the genetic defects causing infertility or subfertility through genetic testing can help both ARTs and NaProTechnology to achieve successful pregnancies. By discovering the underlying causes of infertility, genetic tests enable better family counseling, like the implications of transmitting risk- and disease-alleles to future generations.

Background and Aim: Epilepsy is a neurological disorder in which the altered activity of neurons causes convulsions, periods of unusual behavior and, sometimes, loss of consciousness. The aim of this mini-review is to summarize all the syndromes characterized by epilepsy and for which the associated gene is known., Methods: We searched those syndromes in PubMed and OMIM database., Results: Genetic causes underlie epilepsy in about 40% of individuals. Epilepsies are phenotypically and genetically heterogeneous. Inheritance can be autosomal dominant or recessive or X-linked recessive/dominant., Conclusion: Since epilepsy has high genetic heterogeneity, in diagnostics, the parallel sequencing of a panel of genes may speed up the determination of the molecular etiology and/or establish a risk of recurrence in family members for the purpose of planning appropriate preventive and/or therapeutic measures.

Background: Fetal abnormalities cause 20% of perinatal deaths. Advances in prenatal genetic and other types of screening offer great opportunities for identifying high risk pregnancies., Methods: Through a literature search, here we summarise what are the prenatal diagnostic technique that are being used and how those techniques may allow for prenatal interventions., Results: Next generation sequencing and non-invasive prenatal testing are fundamental for clinical diagnostics because of their sensitivity and accuracy in identifying point mutations, aneuploidies, and microdeletions, respectively. Timely identification of genetic disorders and other fetal abnormalities enables early intervention, such as in-utero gene therapy, fetal drug therapy and prenatal surgery., Conclusion: Prenatal intervention is mainly focused on conditions that may cause death or lifelong disabilities, like spina bifida, congenital diaphragm hernia and sacrococcygeal teratoma; and may be an alternative therapeutic option to termination of pregnancy. However, it is not yet widely available, due to lack of specialized centers.

Dentato-Rubral-pallidoluysian atrophy (DRPLA) is a rare autosomal, dominant, progressive neurodegenerative disease that causes involuntary movements, mental and emotional problems. DRPLA is caused by a mutation in the ATN1 gene that encodes for an abnormal polyglutamine stretch in the atrophin-1 protein. DRPLA is most common in the Japanese population, where it has an estimated incidence of 2 to 7 per million people. This condition has also been seen in families from North America and Europe. We obtained a reprogrammed iPSC line from a Caucasian patient with a juvenile onset of the disease, carrying 64 CAG repeat expansion in the ATN1 gene., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Hereditary multiple osteochondromas (HMO) is a rare autosomal dominant skeletal disorder, caused by heterozygous variants in either EXT1 or EXT2, which encode proteins involved in the biogenesis of heparan sulphate. Pathogenesis and genotype-phenotype correlations remain poorly understood. We studied 114 HMO families (158 affected individuals) with causative EXT1 or EXT2 variants identified by Sanger sequencing, or multiplex ligation-dependent probe amplification and qPCR. Eighty-seven disease-causative variants (55 novel and 32 known) were identified including frameshift (42%), nonsense (32%), missense (11%), splicing (10%) variants and genomic rearrangements (5%). Informative clinical features were available for 42 EXT1 and 27 EXT2 subjects. Osteochondromas were more frequent in EXT1 as compared to EXT2 patients. Anatomical distribution of lesions showed significant differences based on causative gene. Microscopy analysis for selected EXT1 and EXT2 variants verified that EXT1 and EXT2 mutants failed to co-localize each other and loss Golgi localization by surrounding the nucleus and/or assuming a diffuse intracellular distribution. In a cell viability study, cells expressing EXT1 and EXT2 mutants proliferated more slowly than cells expressing wild-type proteins. This confirms the physiological relevance of EXT1 and EXT2 Golgi co-localization and the key role of these proteins in the cell cycle. Taken together, our data expand genotype-phenotype correlations, offer further insights in the pathogenesis of HMO and open the path to future therapies., (© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The Von Hippel-Lindau (VHL) syndrome has been rarely associated with renal oncocytomas, and tumors usually show HIF1 α chronic stabilization. By contrast, oncocytomas mainly associated with respiratory chain (RC) defects due to severe mitochondrial DNA (mtDNA) mutations are incapable of stabilizing HIF1 α , since oxygen consumption by the RC is dramatically diminished and prolylhydroxylase activity is increased by α -ketoglutarate accumulation following Krebs cycle slowdown. Here, we investigate the cooccurrence of a pseudohypoxic condition with oncocytic transformation in a case of VHL-associated renal oncocytoma. While HIF1 α was abundant in nuclei concordantly with defects in VHL, negative staining of its targets carbonic anhydrase IX (CAIX) and glucose transporter GLUT1, usually overexpressed in VHL-associated neoplasms, suggested HIF1 α to be present in its inactive (hydroxylated) form. MtDNA sequencing and immunohistochemistry analyses revealed a MT-CO1 stop-gain mutation and cytochrome c oxidase loss. We suggest that a mitochondrial respiration impairment may lead to hyperhydroxylation of the transcription factor, which we confirmed by specific staining of hydroxylated HIF1 α . Such inactive form hence accumulated in the VHL-deficient tumor, where it may contribute to the benign nature of the neoplasm. We propose that the protumorigenic role of HIF1 α in VHL cancers may be blunted through drugs inhibiting mitochondrial respiratory complexes, such as metformin.

Leber's hereditary optic neuropathy (LHON) is a maternally inherited disorder that causes severe loss of sight in young adults, and is typically associated to mitochondrial DNA (mtDNA) mutations. Heteroplasmy of primary LHON mutations, presence of 'ancillary' mtDNA mutations, and mtDNA copy number are probably correlated with the penetrance and the severity of the disease. In this study, we performed a mutational screening in an Apulian cohort of LHON patients and we found that 41 out of 54 subjects harbored the m.11778G>A mutation, and 13 harbored the m.3460G>A mutation. Whole mtDNA sequencing was performed in three affected subjects belonging to three unrelated m.11778G>A pedigrees to evaluate the putative synergistic role of additional mtDNA mutations in determining the phenotype. Our study suggests to include haplogroup T as a possible genetic background influencing LHON penetrance and to consider the increase of mtDNA copy number as a protective factor from vision loss regardless the hetero/homoplasmic status of LHON primary mutations.

Inactivating mutations of the multiple endocrine neoplasia 1 ( MEN1 ) gene cause MEN1 syndrome, characterized by primary hyperparathyroidism (pHPT), and parathyroid and gastro-entero-pancreatic pituitary tumors. At present, only 14 cases of malignant parathyroid tumor have been associated with the syndrome, with 6 cases carrying an inactivating mutation of the MEN1 gene. The present study presents the case of a 48-year-old female who presented with multigland pHPT and multiple pancreatic lesions. The patient underwent surgery several times for the excision of parathyroid hyperplasia, carcinoma and adenoma. The MEN1 gene was screened, revealing three variants (in cis) at the intron/exon 3 boundary (IVS2-3G>C, c.497A>T and c.499G>T) detected on the DNA of the proband, not shared by her relatives. RNA sequencing revealed that the IVS2-3C>G variant caused the skipping of the exon 3. Therefore, the present study reports on a novel rare association of MEN1 syndrome and parathyroid carcinoma. The reported splicing mutation was previously identified in subjects who always developed malignant lesions; thus, a possible genotype-phenotype association may be considered.

Purpose: Leber's hereditary optic neuropathy (LHON) is a mitochondrial disease that typically causes bilateral blindness in young men. It is characterized by as yet undisclosed genetic and environmental factors affecting the incomplete penetrance., Methods: We identified 27 LHON subjects who possess heteroplasmic primary LHON mutations. Mitochondrial DNA (mtDNA) copy number was evaluated., Results: The presence of centrocecal scotoma, an edematous, hyperemic optic nerve head, and vascular tortuosity, as well as telangiectasia was recognized in affected subjects. We found higher cellular mtDNA content in peripheral blood cells of unaffected heteroplasmic mutation carriers with respect to the affected., Conclusions: The increase of cellular mtDNA content prevents complete loss of vision despite the presence of a heteroplasmic state of LHON primary mutation, suggesting that it is a key factor responsible for penetrance of LHON.

Hyperparathyroidism Jaw-Tumour Syndrome (HPT-JT) is characterized by primary hyperparathyroidism (PHPT), maxillary/mandible ossifying fibromas and by parathyroid carcinoma in 15% of cases. Inactivating mutations of the tumour suppressor CDC73/HRPT2 gene have been found in HPT-JT patients and also as genetic determinants of sporadic parathyroid carcinoma/atypical adenomas and, rarely, typical adenomas, in familial PHPT. Here we report the genetic and molecular analysis of the CDC73/HRPT2 gene in three patients affected by PHPT due to atypical and typical parathyroid adenomas, in one case belonging to familial PHPT. Flag-tagged WT and mutant CDC73/HRPT2 proteins were transiently transfected in HEK293 cells and functional assays were performed in order to investigate the effect of the variants on the whole protein expression, nuclear localization and cell overgrowth induction. We identified four CDC73/HRPT2 gene mutations, three germline (c.679&#95;680delAG, p.Val85&#95;Val86del and p.Glu81&#95;Pro84del), one somatic (p.Arg77Pro). In three cases the mutation was located within the Nucleolar Localisation Signals (NoLS). The three NoLS variants led to instability either of the corresponding mutated protein or mRNA or both. When transfected in HEK293 cells, NoLS mutated proteins mislocalized with a predeliction for cytoplasmic or nucleo-cytoplasmic localization and, finally, they resulted in overgrowth, consistent with a dominant negative interfering effect in the presence of the endogenous protein.

Interstitial deletion of chromosome region 3p14.1, including FOXP1 gene, is relatively rare and, until recently, there were no strong evidences to support the hypothesis that this microdeletion could play a role in the etiology of genomic disorders. Here, we report on an adult patient with a recognizable phenotype of autism, severe speech delay, deficit of motor coordination and typical dysmorphic features. Analysis of a dense whole genome single-nucleotide polymorphism (SNP) array showed a 1Mb interstitial deletion of chromosome region 3p14.1 including the entire coding region of FOXP1 (MIM 605515) gene. In order to study the parental origin of the deletion, we analyzed selected SNPs in the deleted area in the proband and his parents showing Mendelian incompatibilities suggesting a de novo deletion on the chromosome of paternal origin. Despite the frequency of this genomic alteration has not been estimated, our patient confirm the hypothesis that microdeletion of 3p14.1 seems to be a rare cause of cognitive disorders and that haploinsufficiency of FOXP1 may play a role in neurological and language deficits in patients carrying a 3p14.1 deletion. Finally, our patient is also important because useful to further delineate the clinical spectrum secondary to the 3p14.1 microdeletions., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: Hereditary multiple exostosis represents the most frequent bone tumor disease in humans. It consists of cartilage deformities affecting the juxta-ephyseal region of long bones. Usually benign, exostosis could degenerate in malignant chondrosarcoma form in less than 5% of the cases. Being caused by mutations in the predicted tumor suppressor genes, EXT1 (chr 8q23-q24) and EXT2 (chr 11p11-p12) genes, HMEs are usually inherited with an autosomal dominant pattern, although "de novo" cases are not infrequent., Aim: Here we present our genetic diagnostic report on the largest Southern Italy cohort of HME patients consisting of 90 subjects recruited over the last 5years., Results: Molecular screening performed by direct sequencing of both EXT1 and EXT2 genes, by MLPA and Array CGH analyses led to the identification of 66 mutations (56 different occurrences) and one large EXT2 deletion out of 90 patients (74.4%). The total of 21 mutations (20 different occurrences, 33.3%) and the EXT2 gene deletion were novel. In agreement with literature data, EXT1 gene mutations were scattered along all the protein sequence, while EXT2 lesions fell in the first part of the protein. Conservation, damaging prediction and 3-D modeling, in-silico, analyses, performed on three novel missense variants, confirmed that at least in two cases the novel aminoacidic changes could alter the structure stability causing a strong protein misfolding., Conclusions: Here we present 20 novel EXT1/EXT2 mutations and one large EXT2 deletion identified in the largest Southern Italy cohort of patients affected by hereditary multiple exostosis., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Objective: To determine if molecular and immunohistochemical (IHC) features of the HRPT2/CDC73 gene and its product, parafibromin, predict the natural history of parathyroid malignancy, particularly atypical adenoma, as seen in a single-centre patient cohort., Methods: Matched tumor and non-tumor tissues were obtained from 46 patients with parathyroid carcinoma (CA) (n = 15), atypical adenoma (AA) (n = 14) and typical adenoma (TA) (n = 17), as defined by standardized histopathological criteria. Exons and exon-intron boundaries of the CDC73 gene were sequenced to identify germline or somatic mutations. IHC staining for parafibromin was performed and scored as positive if nuclear staining was at least partially IHC-positive., Results: Mutations of CDC73 were observed in 9/15 (60 %) CA, 2/14 (14 %) AA, and 1/17 (6 %) TA tumors. A recurrent two basepair mutation in exon 7 -- c.679&#95;680delAG -- accounted for half of all identified mutations. Absence of parafibromin nuclear staining was noted in 8/12 (67 %) CA, 2/13 (15 %) AA, and 3/17 (18 %) TA tumors. Median follow up times were 88 months for CA, 76 months for AA, and 104 months for TA patients. One patient, a member of a previously reported multiplex family with a germline CDC73 mutation was found to have a second adenoma after removal of an atypical adenoma., Conclusions: Molecular screening and IHC are both useful tools in the differential diagnosis of parathyroid tumors, but both have limited sensitivity and specificity. CDC73 mutations and negative immunostaining were common in atypical adenomas, but no local recurrence was observed in any case with successful surgical removal after follow-up periods of 27 to 210 months.

Cerebral cavernous malformations (CCMs) represent a common autosomal dominant disorder that predisposes patients to haemorrhagic strokes and focal neurological signs. About 56% of the hereditary forms of CCMs have been so far associated with mutations in the KRIT1 (Krev Interaction Trapped 1) gene, located at 7q21.2 (CCM1 locus). We described the complete loss of 7q21.2 locus encompassing the KRIT1 gene and 4 flanking genes in a CCM family by using a dense set of 12 microsatellite markers. The complete loss of the maternal copy of KRIT1 gene region was confirmed by Real-Time Quantitative Polymerase Chain Reaction (RT-QPCR) and the same approach was used for expression analysis. Additional RT-QPCR analysis showed the extension of the deletion, for a total of 700 kb, to the adjacent downstream and upstream-located genes, MTERF, AKAP9, CYP51A1, as well as a partial loss of the ANKIB1 gene. Here we report the molecular characterization of an interstitial small genomic deletion of the 7q21.2 region in a CCMs affected family, encompassing the KRIT1 gene. Our findings confirm the loss of function mechanism for the already known CCM1 locus, without any evident involvement of the other deleted genes. Moreover, our investigations highlight the usefulness of the RT-QPCR to the molecular characterization of the breakpoints genomic deletions and to the identification of internal deleted genes involved in the human genetic diseases.

Primary hyperparathyroidism (PHPT) is a common endocrine disease that is associated with multiple endocrine neoplasia type 1 (MEN1) in approximately 2% of PHPT cases. Lack of a family history and other specific expressions may lead to underestimated MEN1 prevalence in PHPT. The aim of this study was to identify clinical or biochemical features predictive of MEN1 and to compare the severity of the disease in MEN1-related versus sporadic PHPT (sPHPT). We performed a 36-mo cross-sectional observational study in three tertiary referral centers on an outpatient basis on 469 consecutive patients with sporadic PHPT and 64 with MEN1-related PHPT. Serum calcium, phosphate, PTH, 25(OH)D(3), and creatinine clearance were measured, and ultrasound examination of the urinary tract/urography was performed in all patients. In 432 patients, BMD was measured at the lumbar spine (LS) and femoral neck (FN). MEN1 patients showed lower BMD Z-scores at the LS (-1.33 +/- 1.23 versus -0.74 +/- 1.4, p = 0.008) and FN (-1.13 +/- 0.96 versus -0.6 +/- 1.07, p = 0.002) and lower phosphate (2.38 +/- 0.52 versus 2.56 +/- 0.45 mg/dl, p = 0.003) and PTH (113.8 +/- 69.5 versus 173.7 +/- 135 pg/ml, p = 0.001) levels than sPHPT patients. Considering probands only, the presence of MEN1 was more frequently associated with PTH values in the normal range (OR, 3.01; 95% CI, 1.07-8.50; p = 0.037) and younger age (OR, 1.61; 95% CI, 1.28-2.02; p = 0.0001). A combination of PTH values in the normal range plus age <50 yr was strongly associated with MEN1 presence (OR, 13.51; 95% CI, 3.62-50.00; p = 0.0001). In conclusion, MEN1-related PHPT patients show more severe bone but similar kidney involvement despite a milder biochemical presentation compared with their sPHPT counterparts. Normal PTH levels and young age are associated with MEN1 presence.

There are many well-studied examples of human phenotypes resulting from nonsense or frameshift mutations that are modulated by Nonsense-Mediated mRNA Decay (NMD), a process that typically degrades transcripts containing premature termination codons (PTCs) in order to prevent translation of unnecessary or aberrant transcripts. Different types of germline mutations in the VHL gene cause the von Hippel-Lindau disease, a dominantly inherited familial cancer syndrome with a marked phenotypic variability and age-dependent penetrance. By generating the Drosophila UAS:Upf1(D45B) line we showed the possible involvement of NMD mechanism in the modulation of the c.172delG frameshift mutation located in the exon 1 of Vhl gene. Further, by Quantitative Real-time PCR (QPCR) we demonstrated that the corresponding c.163delG human mutation is targeted by NMD in human HEK 293 cells. The UAS:Upf1(D45B) line represents a useful system to identify novel substrates of NMD pathway in Drosophila melanogaster. Finally, we suggest the possible role of NMD on the regulation of VHL mutations.

Central nervous system hemangioblastomas are benign vascular tumours that may present sporadically or as manifestation of the von Hippel-Lindau (VHL) disease. VHL Syndrome is a rare autosomal dominant disorder characterized, besides hemangioblastomas, by susceptibility to multifocal and bilateral renal cell carcinoma and cysts, retinal angiomas, pheochromocytoma, epididymis cystoadenoma, pancreatic cysts and/or islet cell tumours. Germline mutations of VHL tumour suppressor gene cause the VHL disease, while somatic mutations have been associated with sporadic hemangioblastomas and clear-cell renal carcinomas. We identified an 11-bp duplication in the promoter region of the VHL gene in a VHL-affected individual. Functional analysis revealed that this variant affects the binding or the binding affinity of one or more transcription factors that regulate the transcription of VHL in vivo, reducing the endogenous levels of VHL mRNA. Moreover, consistent with the "two hits" model, microsatellite analysis of hemangioblastoma tissue from this patient revealed Allelic Imbalance for the chromosomal region near the VHL gene. We propose that these molecular events, through a loss of pVHL function, lead to the onset of the VHL-related tumours in that individual.

Object: Although there is general agreement on the methods of treatment for symptomatic supratentorial cerebral cavernous malformations (CMs) located in noneloquent areas, some controversy exists regarding the management of cerebral CMs that are asymptomatic and/or located in eloquent or deep areas. Moreover, recent advances in genetic findings could influence both standard clinical management and the follow-up strategy in affected individuals. Thus, the objective of this study was to develop, based on the authors' experience and a literature review, a management algorithm to deal with supratentorial cerebral CMs., Methods: The authors retrospectively reviewed the clinical data related to 118 patients who underwent surgery for symptomatic supratentorial cerebral CMs at their institution. Twenty-eight of 118 patients harbored multiple lesions, and nine of these 28 patients had a clinically positive familial history. Genetic investigations were performed in 89 patients (75%)., Conclusions: Surgery for supratentorial cerebral CMs in noneloquent locations is safe and curative. In cerebral CMs located in deep and eloquent areas and with symptoms including progressive neurological deficits, evidence of hemorrhage, and uncontrolled seizures, surgical treatment according to an integrated plan based on frameless stereotactic guidance and functional magnetic resonance imaging is recommended and results in acceptably low morbidity. The data support the need for long-term imaging follow up in all patients, careful preoperative vascular studies to detect associated venous anomalies, and the importance of genetic mutational analysis. The DNA screening protocol will change the care of family members of patients with familial forms of cerebral CMs, because affected asymptomatic family members may benefit by early detection of lesions. At the same time, the exclusion of family members who are not carriers of the mutation as members of the population at risk reduces the economic and psychological burden of clinical and instrumental monitoring.

Transforming growth factor beta1 (TGF-beta1) is abundant in bone and is an important regulator of the osteoclastic-osteoblastic interaction (coupling). The sequence variation, 713-8delC in the TGF-beta1 gene has previously been found to be associated with very low bone mass in osteoporotic women and with increased bone turnover in both osteoporotic and normal women. The possible association of this polymorphism with bone mass and bone turnover has now been investigated in 256 postmenopausal Italian women. A significant association of TGF-beta1 with bone mass was detected in the populations. Subjects carrying the sequence variation 713-8delC (Tt) genotype showed a significantly lower bone mineral density (BMD) at the hip than those without sequence variation in the genotype (TT). Individuals carrying the tt genotype have a more severe osteoporosis (P=0.0001 vs. TT and Tt genotypes). The frequency of the fragility fractures was significantly lower in individuals with TT genotype than in those with the Tt and tt genotypes (X2=21.9; P=0.006). Furthermore a significant association was found between 713-8delC and bone turnover. The results suggest a strong evidence for an association among the 713-8delC allele of the TGF-beta1 gene and the femoral BMD, the prevalence of osteoporotic fractures, and finally a high bone turnover in a sample of Italian postmenopausal women.

A transcription map was generated of a 1 Mb interval including the HFE gene on 6p22. Thirty-seven unique cDNA fragments were characterised following their retrieval from hybridisation of immobilised YACs to primary pools of cDNAs prepared from RNA of foetal brain, human liver, foetal human liver, placenta, and CaCo2 cell line. All cDNA fragments were positioned on the physical map on the basis of presence in aligned and overlapping YACs and cosmid clones of the region. The isolated cDNAs together with established or published sequence tagged sites (STSs) and markers provided sufficient landmark density to cover approximately 90% of the 1 Mb interval with cosmid clones. The precise localisation of two known genes (NPT1 and RING finger protein) was established. A minimum of 14 additional transcription units has also been integrated. Twenty-eight cDNA fragments showed no similarity with known sequences, but 20 of these detected discrete mRNAs upon northern analysis. Their characterisation is still under investigation. Eleven new polymorphisms were also identified and localised, and the HFE genomic structure was better defined. This integrated transcription map considerably extends a recently published map of the HFE region. It will be useful for the identification of genetic defects mapping to this region and for providing template resources for genomic sequencing.

Neurofibromatosis type 1 (NF1) of von Recklinghausen is a common autosomal dominant disorder, characterized by peripheral neurofibromas, café-au-lait spots and Lisch nodules of the iris. The high mutation rate at the NF1 locus results in a wide range of molecular abnormalities. We have scanned 14 different exons from the first part of the NF1 gene using the RNA-single strand conformation polymorphism (RNA-SSCP) method in a series of 40 NF1 patients. Three novel mutations, two nonsense and one missense, and two polymorphisms have been detected in familial cases. Genotype-phenotype correlations have been investigated, but no particular association has been detected. After this screening, the majority of NF1 chromosomes has not yet been characterized, confirming the difficulty in detecting the defect underlying NF1 in most families, even following extensive DNA analysis.

Hereditary hemochromatosis (HFE) is an inherited disorder whose gene lies in the proximity of the histocompatibility antigen (HLA) class I region, on 6p21.3. Despite efforts in refining the HFE region, a number of informative DNA markers, linked to the disease locus and amenable to use in an assay based on the polymerase chain reaction (PCR) is available. The gene content of this region is high, and the HFE gene has not so far been identified. We have used a strategy based on PCR protocols potentially able to detect both polymorphisms and expressed sequences. This approach has been applied to a 700-kb stretch (approximately) of DNA corresponding to the insert of a Centre d'Etude du Polymorphisme Humain yeast artificial chromosome (225 B1) of the possible candidate region. Five new polymorphisms have been detected among 20 specific fragments isolated. Four of them are tightly linked to the HFE locus. Because of the strong linkage disequilibrium with the disease demonstrated by these markers, they could represent starting points for the identification and characterization of the HFE gene. The remaining non-polymorphic fragments, being amplifiable and in most cases linked to NotI sites, may be useful starting points for the generation of a genomic contig of band 6p21.3 and for gene identification.