Prenatal molecular diagnosis of X-linked hydrocephalus via a silent C924T mutation in the L1CAM gene.

We present a case of a patient whose L1CAM gene in X-chromosome has a C924T transition. Her first son's ventriculomegaly was prenatally detected. A mature infant was born, his head circumference was large, and thumbs were bilaterally adducted. X-linked hydrocephalus (XLH) was suspected. The DNA examination revealed that both her and boy's LICAM gene had a C924T transition. She became pregnant 5 years later and amniocentesis was performed. The results of cytogenetic analysis revealed that the fetus was female. She continued her pregnancy and delivered a healthy girl. She again became pregnant 3 years later. The chromosomal analysis revealed that the fetus was male. Fetal DNA analysis determined that the fetus had the inherited mutation. She chose to terminate the pregnancy. A C924T mutation can be disease causing for XLH, and the detection of this mutation would aid in genetic counseling for the prenatal diagnosis of XLH.