Musculoskeletal phenotypes in 3q29 deletion syndrome

3q29 deletion syndrome (3q29del) is a rare genomic disorder caused by a 1.6 Mb deletion (hg19, chr3:195725000-197350000). 3q29del is associated with neurodevelopmental and psychiatric phenotypes, including an astonishing >40-fold increased risk for schizophrenia, but medical phenotypes are less well-described. We used the online 3q29 registry (3q29deletion.org) to recruit 57 individuals with 3q29del (56.14% male) and requested information about musculoskeletal phenotypes with a custom questionnaire. 85.96% of participants with 3q29del reported at least one musculoskeletal phenotype. Congenital anomalies were most common (70.18%), with pes planus (40.35%), pectus excavatum (22.81%), and pectus carinatum (5.26%) significantly elevated relative to the pediatric general population. 49.12% of participants reported fatigue after 30 minutes or less of activity. Bone fractures (8.77%) were significantly elevated relative to the pediatric general population, suggesting 3q29del impacts bone strength. Participants commonly report receiving medical care for musculoskeletal complaints (71.93%), indicating that these phenotypes impact quality of life for individuals with 3q29del. This is the most comprehensive description of musculoskeletal phenotypes in 3q29del to date, suggests ideas for clinical evaluation, and expands our understanding of the phenotypic spectrum of this syndrome.