Sequence variants in CRB2 cause a syndrome with greatly elevated maternal serum alpha-fetoprotein and amniotic fluid alpha-fetoprotein levels, cerebral ventriculomegaly and renal findings similar to Finnish congenital nephrosis.
At Kuopio University Hospital, a total of 1303 pregnant women were offered carrier screening for CNF at the time of first trimester nuchal fold translucency measurement when fetally derived alpha-fetoprotein is still produced by the yolk sac.