Search

Background: Benign adult familial myoclonic epilepsy (BAFME) is an autosomal dominant disorder characterized by cortical tremors and seizures. Six types of BAFME, all caused by pentanucleotide repeat expansions in different genes, have been reported. However, several other BAFME cases remain with no molecular diagnosis. Objectives: We aim to characterize clinical features and identify the mutation causing BAFME in a large Malian family with 10 affected members. Methods: Long‐read whole genome sequencing, repeat‐primed polymerase chain reaction and RNA studies were performed. Results: We identified TTTTA repeat expansions and TTTCA repeat insertions in intron 4 of the RAI1 gene that co‐segregated with disease status in this family. TTTCA repeats were absent in 200 Malian controls. In the affected individuals, we found a read with only nine TTTCA repeat units and somatic instability. The RAI1 repeat expansions cause the only BAFME type in which the disease‐causing repeats are in a gene associated with a monogenic disorder in the haploinsufficiency state (ie, Smith‐Magenis syndrome [SMS]). Nevertheless, none of the Malian patients exhibited symptoms related to SMS. Moreover, leukocyte RNA levels of RAI1 in six Malian BAFME patients were no different from controls. Conclusions: These findings establish a new type of BAFME, BAFME8, in an African family and suggest that haploinsufficiency is unlikely to be the main pathomechanism of BAFME. © 2023 International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

To maximize the potential of genomics in medicine, it is essential to establish databases of genomic variants for ethno‐geographic groups that can be used for filtering and prioritizing candidate pathogenic variants. Populations with non‐European ancestry are poorly represented among current genomic variant databases. Here, we report the first high‐density survey of genomic variants for the Thai population, the Thai Reference Exome (T‐REx) variant database. T‐REx comprises exome sequencing data of 1092 unrelated Thai individuals. The targeted exome regions common among four capture platforms cover 30.04 Mbp on autosomes and chromosome X. 345 681 short variants (18.27% of which are novel) and 34 907 copy number variations were found. Principal component analysis on 38 469 single nucleotide variants present worldwide showed that the Thai population is most genetically similar to East and Southeast Asian populations. Moreover, unsupervised clustering revealed six Thai subpopulations consistent with the evidence of gene flow from neighboring populations. The prevalence of common pathogenic variants in T‐REx was investigated in detail, which revealed subpopulation‐specific patterns, in particular variants associated with erythrocyte disorders such as the HbE variant in HBB and the Viangchan variant in G6PD. T‐REx serves as a pivotal addition to the current databases for genomic medicine. [ABSTRACT FROM AUTHOR]

The use of rapid DNA sequencing technology in severely ill children in developed countries can accurately identify diagnoses and positively impact patient outcomes. This study sought to evaluate the outcome of Thai children and adults with unknown etiologies of critical illnesses with the deployment of rapid whole exome sequencing (rWES) in Thailand. We recruited 54 unrelated patients from 11 hospitals throughout Thailand. The median age was 3 months (range, 2 days–55 years) including 47 children and 7 adults with 52% males. The median time from obtaining blood samples to issuing the rWES report was 12 days (range, 5–27 days). A molecular diagnosis was established in 25 patients (46%), resulting in a change in clinical management for 24 patients (44%) resulting in improved clinical outcomes in 16 patients (30%). Four out of seven adult patients (57%) received the molecular diagnosis which led to a change in management. The 25 diagnoses comprised 23 different diseases. Of the 34 identified variants, 15 had never been previously reported. This study suggests that use of rWES as a first‐tier investigation tool can provide tremendous benefits in critically ill patients with unknown etiology across age groups in Thailand. [ABSTRACT FROM AUTHOR]

Cole‐Carpenter syndrome (CCS), commonly classified as a rare type of osteogenesis imperfecta, is a disorder with severe bone fragility, craniosynostosis, and distinct facial features. Recently, the heterozygous missense mutation, c.1178A>G, p.Tyr393Cys, in exon 9 of P4HB which encodes protein disulfide isomerase, has been found in three Caucasian patients with CCS. Ethnic background is known to affect clinical manifestations, especially facial features of dysmorphic syndromes. Here, we describe the first Asian CCS patient possessing the recurrent mutation in P4HB. Although she had several common features of CCS including bulging forehead, ocular proptosis, midface hypoplasia, long bone deformity, popcorn epiphyses, vertebral fractures, and scoliosis, she did not have hydrocephalus, wormian bones, and dentinogenesis imperfecta, commonly seen in Caucasian patients. Interestingly, she is the only one without macrocephaly. Radiologically, metadiaphyseal fractures of the long bones with metaphyseal sclerosis were found, substantiating that they provide a definitive radiological feature of CCS. In addition, we showed for the first time a three‐dimensional facial scan of a patient with CCS. She had been given intravenous bisphosphonate since the age of 9 months and had responded well. Our study presents the clinical features of the first Asian patient, supports metaphyseal scleroses and fractures as radiological clues, strengthens early bisphosphonate administration, and confirms the etiologic role of the c.1178A>G variant in P4HB across populations. [ABSTRACT FROM AUTHOR]

Patient-3 had suffered long bone fractures 1-2 times/year in the past 7 years despite being treated with IV pamidronate, similar to previous observations that I SERPINF1 i patients receiving long-term bisphosphonate had improved lumbar spine area BMD and higher final height, but still had frequent lower extremity fractures and scoliosis.4,5 The five pathogenic variants identified in three patients have not been previously reported, expanding the mutational spectrum of AR-OI. (A-D) Patient-1: fractures of femurs and humeri, bowed radii and ulnae, kyphosis, vertebral compression fractures, and BMP1 variants. Radiographs demonstrated multiple fractures and long bone and vertebrae deformities (Figure 1A-C), and intravenous pamidronate was started that resulted in no further fractures. [Extracted from the article]

Skeletal dysplasias are a complex group of more than 350 disorders with phenotypic and genotypic heterogeneity affecting bone and cartilage growth. We studied a 2-year-old girl and her 21-year-old mother with disproportionate short stature. In addition to typical features of hypochondroplasia found in both patients, the child had deformities of the extremity bones, metaphyseal flares, and bilateral transverse (Bowdler) fibular spurs with overlying skin dimples detected at birth. Intravenous pamidronate was started in the child since the age of 17 days, and then every two months. Exome sequencing revealed that the girl was heterozygous for a missense mutation (c.1651A>G, p.Ile538Val) in exon 13 of FGFR3, a known mutation for hypochondroplasia, inherited from her mother. Interestingly, the child also harbored compound heterozygous missense mutations in exon 12 of ALPL, c.1460C>T (p.Ala487Val) inherited from her mother and c.1479C>A (p.Asn493Lys) inherited from her healthy father. The former mutation was previously reported in perinatal hypophosphatasia while the latter was novel. Constantly reduced serum alkaline phosphatase levels including the one before the pamidronate administration and a substantially elevated level of plasma pyridoxal 5′-phosphate detected at age 28 months supported the diagnosis of hypophosphatasia. After a definite diagnosis was achieved, pamidronate was withdrawn at the age of 28 months. No adverse events were observed during pamidronate therapy. In conclusion, we describe a unique case with monoallelic FGFR3 and biallelic ALPL mutations leading to features of both hypochondroplasia and hypophosphatasia. [ABSTRACT FROM AUTHOR]

The article focuses on research related to immune defects in leukocyte adhesion deficiency (LAD). Topics discussed include characterization of LAD through impairment of phagocyte adhesion, identification of a LAD-III patient with a mild clinical phenotype having immunologic defects involving both innate and adaptive immune responses, and treatment of the patient through regular intravenous immunoglobulin (IVIG) therapy.

Primary hyperoxaluria type 1 (PH1) is an autosomal recessive disorder caused by mutations in the alanine:glyoxylate aminotransferase ( AGXT) gene, located on chromosome 2q37. Mutant AGXT leads to excess production and excretion of oxalate, resulting in accumulation of calcium oxalate in the kidney, and progressive loss of renal function. Brachydactyly mental retardation syndrome (BDMR) is an autosomal dominant disorder, caused by haploinsufficiency of histone deacetylase 4 ( HDAC4), also on chromosome 2q37. It is characterized by skeletal abnormalities and developmental delay. Here, we report on a girl who had phenotypes of both PH1 and BDMR. PCR-sequencing of the coding regions of AGXT showed a novel missense mutation, c.32C>G (p.Pro11Arg) inherited from her mother. Functional analyses demonstrated that it reduced the enzymatic activity to 31% of the wild-type and redirected some percentage of the enzyme away from the peroxisome. Microsatellite and array-CGH analyses indicated that the proband had a paternal de novo telomeric deletion of chromosome 2q, which included HDAC4. To our knowledge, this is the first report of PH1 and BDMR, with a novel AGXT mutation and a de novo telomeric deletion of chromosome 2q. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]