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Arthrogryposis is a clinical feature defined by congenital joint contractures in two or more different body areas which occurs in between 1/3000 and 1/5000 live births. Variants in multiple genes have been associated with distal arthrogryposis syndromes. Heterozygous variants in MYH3 have been identified to cause the dominantly-inherited distal arthrogryposis conditions, Freeman-Sheldon syndrome, Sheldon-Hall syndrome, and multiple pterygium syndrome. In contrast, MYH3 variants underlie both dominantly and recessively inherited Contractures, Pterygia, and Spondylocarpotarsal Fusion syndromes (CPSFS) which are characterized by extensive bony abnormalities in addition to congenital contractures. Here we report two affected sibs with distal arthrogryposis born to unaffected, distantly related parents. Sequencing revealed that both sibs were homozygous for two ultra-rare MYH3 variants, c.3445G>A (p.Glu1149Lys) and c.4760T>C (p.Leu1587Pro). Sequencing and deletion/duplication analysis of 169 other arthrogryposis genes yielded no other compelling candidate variants. This is the first report of biallelic variants in MYH3 being implicated in a distal arthrogryposis phenotype without the additional features of CPSFS. Thus, akin to CPSFS, both dominant and recessively inherited distal arthrogryposis can be caused by variants in MYH3.
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http://dx.doi.org/10.1111/cge.14570 | DOI Listing |
Medicine (Baltimore)
August 2025
Department of Neonatology, Hangzhou Women's Hospital, Hangzhou, Zhejiang Province, China.
Rationale: Contractures, pterygia, and spondylocarpotarsal fusion syndrome (CPSFS) comprises a group of extremely rare genetic disorders characterized by congenital craniofacial and musculoskeletal abnormalities. With fewer than 500 cases reported globally, this scarcity contributes to limited clinical recognition, frequent diagnostic delays or errors, and missed opportunities for timely intervention. We present this case to enhance awareness of CPSFS and report a novel pathogenic variant in MYH3 (previously undocumented in the literature) that broadens the known mutational spectrum of MYH3 and enriches the phenotypic profile of CPSFS.
View Article and Find Full Text PDFMol Genet Genomic Med
August 2025
Genomics and Clinical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.
Background: Distal arthrogryposis with impaired proprioception and touch (DAIPT) is a rare autosomal recessive neurological disease characterized by progressive alteration of mechanosensation. DAIPT is caused by loss of function variants in the PIEZO2 gene that encodes an ionic channel involved in mechanotransduction signaling. Our study started from the case of an 11-year-old boy with skeletal and neuromuscular features suggestive of DAIPT.
View Article and Find Full Text PDFNeuromuscul Disord
July 2025
Centre for Neuromuscular Diseases, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK.
Arthrogryposis multiplex congenita (AMC) is associated with >150 genes, including ADGRG6, which codes for an adhesion G protein-coupled receptor. Biallelic loss of function variants in ADGRG6 have been linked to lethal congenital contracture syndrome. Here we present an atypical, milder phenotype associated with a novel ADGRG6 variant.
View Article and Find Full Text PDFNeuromuscul Disord
June 2025
Yeditepe University Faculty of Medicine, Department of Pediatrics, Division of Pediatric Neurology, Istanbul, Turkey.
PIEZO2 is a mechanosensitive ion channel essential for somatosensation, including proprioception, touch and interoception, enabling the detection of external and internal mechanical stimuli. Pathogenic variants in PIEZO2 cause mechanosensitivity disorders, predominantly affecting musculoskeletal system. This multicenter study reports on 26 patients (14 females and 12 males; ages 1-51 years) from 23 independent families; 21 with biallelic and 5 with heterozygous variants.
View Article and Find Full Text PDFAustralas J Ultrasound Med
August 2025
Medical Genetics Unit Azienda USL-IRCCS di Reggio Emilia Reggio Emilia Italy.
Background: Ultrasound diagnosis of fetal skeletal conditions remains challenging. is a gene that encodes the embryonic myosin heavy chain; it is important for skeletal and muscular development and is strongly expressed during fetal development. Variants in are involved in distal arthrogryposes 2A and 2B3 and in spondyocarpotarsal synostosis syndrome with contractures and pterygia, contractures of proximal and distal joints, variable spine anomalies and vertebral, carpal and tarsal fusions.
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