Musculoskeletal abnormalities in a large international cohort of boys with 49,XXXXY

Document Type

Journal Article

Publication Date



American Journal of Medical Genetics, Part A




49,XXXXY; musculoskeletal health; orthopedics; physical therapy; sex chromosome abnormalities and aneuploidies; X and Y chromosomal variations


© 2020 Wiley Periodicals, Inc. 49,XXXXY is the rarest X and Y chromosomal variation, with an incidence of 1 in 80,000–100,000 live male births and has been associated with numerous musculoskeletal abnormalities. Data was collected from an international cohort of boys with 49,XXXXY over 10 years. Children were evaluated by a multidisciplinary team consisting of a pediatric orthopedist, a neurogeneticist, a neurodevelopmentalist, and two physical therapists. Increased rates of torticollis (32.4%), hamstring tightness (42%), radioulnar synostosis (67.6%), pes planus (65.2%), and other foot abnormalities (86.9%) were observed. Several anomalies increased with age, specifically hamstring tightness, kyphosis, and scoliosis. The elucidation of the orthopedic profile of this population is necessary in order to provide healthcare providers with current medical information. This research further supports the necessity for the comprehensive multidisciplinary treatment of boys with 49,XXXXY.

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