Absent inner dynein arms in a fetus with familial hydrocephalus-situs abnormality.

We report a family in which a healthy, unrelated couple had a male fetus with bilateral ventriculomegaly, a normal liveborn girl, a hydatidiform molar pregnancy, a female fetus with ventriculomegaly and situs abnormalities, and a male fetus with hydrocephalus, a three-lobed left lung, and defective tracheal cilia with absent inner dynein arms and a single centriole. A mutation analysis of FOXJ1 and POLL in the last fetus with ciliary defect revealed no mutation within their coding regions. The presence of three affected fetuses of both sexes in a family with phenotypically normal parents suggests that the condition was inherited as an autosomal recessive trait. A thorough evaluation of the thoracic and abdominal situs is recommended before counseling a family of a child with hydrocephalus, because the recognition of situs defects may point to the diagnosis of primary ciliary defect and recurrence risk of 25% for siblings. This figure is much higher than the general risk of 1-2% for siblings of a patient with isolated hydrocephalus.