G. Suthers et al., Skewed sex ratios in familial holoprosencephaly and in people with isolated single maxillary central incisor, J MED GENET, 36(12), 1999, pp. 924-926
Citations number
25
Categorie Soggetti
Research/Laboratory Medicine & Medical Tecnology","Molecular Biology & Genetics
Autosomal dominant holoprosencephaly is a rare but well documented entity a
nd it can be the result of mutations in the Sonic Hedgehog gene (SHH). The
transmitting parent may be normal or have a single maxillary central inciso
r.
We describe a skewed sex ratio among the transmitting parents with SHH muta
tions, with more mothers than fathers having the mutation (p=0.002). The me
chanism underlying this skewed sex ratio is not clear; the SHH mutations do
not involve triplet repeats, imprinting is plausible but untested, and the
re is no evidence that the risk of holoprosencephaly is greater among males
carrying such a mutation (p=0.15). We considered the possibility that male
s with such a mutation are at greater risk of other malformations outside t
he central nervous system, which could reduce their reproductive fitness.
To avoid ascertainment bias in identifying children with various malformati
ons in kindreds with familial holoprosencephaly, we reviewed the reports of
people with single maxillary central incisor and no other congenital malfo
rmations. Of the 16 cases identified, 13 were female (p=0.0085).
We suggest that boys with mutations associated with autosomal dominant holo
prosencephaly may be at greater risk of major malformations outside the cen
tral nervous system than girls.