LAUSR

We describe a female infant with X-linked chondrodysplasia punctata (CDPX1) as a result of maternal isodisomy of the X chromosome. Targeted Sanger sequencing and targeted next-generation sequencing of ARSL were used to test for the familial variant. This patient was homozygous for ARSL NM_000047.2: c.1227_1228delinsAT p.(Ser410Cys) familial variant, consistent with a diagnosis of CDPX1. Uniparental disomy is a type of chromosomal variation. Although not necessarily pathogenic, it can cause imprinting disorders and X-linked recessive disorders in females, and be a cause of autosomal recessive conditions when only one parent is a carrier. The patient described highlights that uniparental disomy can be a rare cause of X-linked recessive conditions. This mode of inheritance has not been previously described in this condition.