L1CAM mutation in association with X-linked hydrocephalus and Hirschsprung's disease.

X-linked hydrocephalus (XLH) is characterized by increased intracranial ventricle size and head circumference secondary to aqueduct of Sylvius congenital stenosis. Exceedingly rare is the concurrence of XLH and Hirschsprung's disease (HSCR) with a theoretical incidence of 1 in 125-250 million cases. Herein, we are describing a case of a patient with concurrent XLH and HSCR. The patient was delivered via cesarean section at 37 weeks gestation and underwent uneventful ventriculoperitoneal shunt placement. As a part of a workup for constipation, we performed a rectal biopsy, which was consistent with HSCR. Genetics testing showed hemizygous for R558X hemizygous mutation in the L1CAM gene. A C --> T nucleotide substitution in exon 13 resulted in replacement of an arginine codon with a stop codon, a nonsense mutation. Although it is widely accepted that HSCR represents the failure of early embryonic neural crest cells to migrate properly, the exact mechanism is not known. The association of HSCR with XLH in the presence of L1CAM mutations remains quite interesting because cell adhesion molecules are involved in the proper migration of neural components throughout the body. Additional studies are necessary to fully elucidate the relationship between XLH and HSCR in the presence of L1CAM mutations.