A de novo 1q23.3-q24.2 deletion combined with a GORAB missense mutation causes a distinctive phenotype with cutis...

Gerodermia osteodysplastica is a recessive segmental progeroid disorder mainly characterized by wrinkled skin, generalized connective tissue weakness, infantile onset osteoporosis and normal intelligence. Coding mutations in GORAB, localized on chromosome 1q24.2, are the cause of this disease. 1q24 deletions underlie a spectrum of disorders with intellectual disability and ear abnormalities as phenotypic hallmarks. Here we report on an individual from Azerbaijan originating from a non-consanguineous couple showing short stature, cutis laxa, frequent fractures, facial dysmorphism, cup-shaped ears and intellectual disability. Sanger sequencing of GORAB revealed the seemingly homozygous missense mutation p.Ser175Phe. This mutation was detected in a heterozygous state in the clinically unaffected mother, but was absent in the healthy father. We performed copy-number investigations by high-resolution array-CGH and PCR approaches and found an ~6 Mb de novo deletion spanning 1q23.3-q24.2 in the affected boy. This novel combination of genetic defects very well explains the phenotype that goes beyond the usual presentation of gerodermia osteodysplastica. Our data provide new insight into the phenotypic spectrum of 1q23-q25 deletions and shows that the combination with another pathogenic allele can lead to more severe clinical manifestations.