Diastrophic dysplasia: prenatal diagnosis and review of the literature.

CONTEXT Diastrophic dysplasia is a type of osteochondrodysplasia caused by homozygous mutation in the gene DTDST (diastrophic dysplasia sulfate transporter gene). Abnormalities occurring particularly in the skeletal and cartilaginous system are typical of the disease, which has an incidence of 1 in 100,000 live births. CASE REPORT The case of a pregnant woman, without any consanguineous relationship with her husband, whose fetus was diagnosed with skeletal dysplasia based on ultrasound findings and DNA tests, is described. An obstetric ultrasound scan produced in the 16th week of gestation revealed characteristics that guided the clinical diagnosis. Prominent among these characteristics were rhizomelia of the lower and upper limbs (shortening of the proximal portions) and mesomelia (shortening of the intermediate portions). Both upper limbs showed marked curvature, with the first finger of the upper limbs in abduction and clinodactyly of the fifth finger. Molecular analysis using the polymerase chain reaction (PCR) and gene sequencing detected mutations that had already been described in the literature for the gene DTDST, named c.862C > T and c.2147_2148insCT. Therefore, the fetus was a compound heterozygote, carrying two different mutations. CONCLUSIONS Prenatal diagnosis of this condition allowed a more realistic interpretation of the prognosis, and of the couple's reproductive future. This case report shows the contribution of molecular genetics towards the prenatal diagnosis, for which there are few descriptions in the literature.