Prenatal diagnosis of osteopathia striata with cranial sclerosis.

Osteopathia striata with cranial sclerosis (OSCS) is a rare X-linked dominant genetic disorder resulting mutation in the WTX gene. Clinically, OSCS presents with linear striations in the metaphyseal region of the long bones and pelvis in combination with sclerosis of the cranium and face. A twenty-seven year old G5T1P3A0L2 woman with a history of periand neonatal infant male deaths was referred to us at 22 weeks, 6 days into her recent pregnancy. Ultrasound evaluation identified a male fetus, bilaterally enlarged lateral ventricles, a cloverleaf skull, suspected bilateral cleft lip, nuchal thickening, bilateral bowed radii and ulnae, gastroschisis with herniated viscera, bilateral absent fibula and clubfeet. The results of prenatal testing identified a male fetus with a 330kb Xq11.1 deletion involving the entire WTX gene. Initial microarray analysis of maternal blood identified a normal female karyotype, 46,XX. FISH analysis with a BAC clone mapped to the WTX gene identified low-level mosaicism in blood and buccal samples, 17% and 15%, respectively, which explained the negative maternal microarray result.