A homozygous variant in FGFR3 causing lethal skeletal dysplasia.

Homozygous achondroplasia, due to biallelic pathogenic Fibroblast Growth Factor Receptor 3 (FGFR3) variants, is the homozygous lethal expression of an autosomal dominant skeletal dysplasia and is clinically distinct from the classical heterozygous form. We describe a male infant born to two achondroplastic heterozygous parents with severe rhizomelic shortening and radiographic features typical of homozygous achondroplasia. Molecular analysis revealed a homozygous c.1138G>A (p.Gly380Arg) variant in FGFR3. The infant developed progressive respiratory compromise and died at 63 days of age due to pulmonary hypoplasia-related respiratory failure.