Cantú syndrome is caused by
gain-of-function mutations in
genes encoding
subunits of
ATP-sensitive potassium channels (KATP channels), including
ABCC9 (encoding the sulfonylurea receptor 2 or SUR2) and
KCNJ8 (encoding Kir6.1). It is apparently inherited in an
autosomal dominant fashion. Both the
ABCC9 and
KCNJ8 genes are located on the short arm of
chromosome 12 (12p12). In one study, mutations in
ABCC9 were responsible for 25 of 31cases of Cantú syndrome. Physiologically, SUR2 is significant in
vascular relaxation, among other effects. An increase in O2 tension after birth, plus decreasing
PGE2 (a common prostaglandin) causes inhibition of voltage-gated
potassium channels and contraction of
smooth muscle (in ductus). The effects of
KATP potassium channel openers like
minoxidil,
diazoxide, and
pinacidil have been found to mimic the symptoms of Cantú syndrome. Examples of these KATP potassium channel opener effects include
hypertrichosis,
pericardial effusions,
pulmonary hypertension,
edema, and
coarsening of facial features, among others. Relatedly, there has been concern that excessive doses of minoxidil and other KATP potassium channel openers might cause a "drug-induced Cantú syndrome". ==Diagnosis==