Broadening the phenotypic and genetic spectrum of ERBB2-associated multisystem congenital disorder

ERBB2 has been implicated in rare multisystem developmental disorders, with only two siblings carrying a homozygous missense variant reported to date. We describe an additional patient with a complex congenital phenotype and novel compound heterozygous variants in ERBB2 : c.1018C>T (p.Arg340Ter) and c.3412+1_3412+13del (p.?). A 7-year-old male presented at birth with hypotonia, bilateral talipes equinovarus, adducted thumbs, camptodactyly of the index fingers, and craniofacial dysmorphic features. His clinical course included delayed motor and speech milestones, abnormal gait, and chronic constipation requiring long-term laxative use. The patient underwent multiple orthopedic and ophthalmologic surgeries and continues with supportive therapies. Cognitive development remains preserved. This case represents the possible phenotypic extension and contributes to the expanding genetic spectrum of ERBB2-related disorders. Not applicable.