After fetal blood sampling, a pathogenic deletion of 1511bp in <i>L1CAM</i>, chromosome X: 153131395-153132905(hg19/GRCh37)/NM_000425.4: c.2043_2432-121del1511 leading to deletion of fibronectin type-III repeats I-II, was identified in the fetus with hydrocephalus inherited from the mother by an exome sequence. The gene discussed is FN1; the disease is Hydrocephalus.