Hypokalemic periodic paralysis (HypoPP) is an autosomal dominant disorder characterized by periodic attacks of muscle weakness associated with a decrease in the serum potassium level. Several mutations in the skeletal muscle calcium channel α-subunit gene CACNA1S have been documented to be causative for HypoPP, but mutations in other genes have also been implicated in HypoPP. To further reveal the genetic causes of HypoPP, we genotyped members of a five-generational Chinese family with HypoPP patients and identified a novel His916Gln mutation in all male HypoPP patients of the family. Clinical analysis demonstrated that the penetrance of the mutation was complete in male carriers, but we did not find evident clinical features in female carriers. This study expanded the spectrum of CACNA1S mutations associated with HypoPP and demonstrated a gender difference in the penetrance of the disease.

BackgroundCerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited disease leading to recurrent ischemic stroke and vascular dementia. Numerous mutations in the 23 exons of the NOTCH3 gene have been reported to cause CADASIL in Caucasian populations, but the full spectrum of genetic changes leading to this disease is yet to be known and, especially, very few reports are available on CADASIL in Asian populations.Methods and ResultsWe genotyped members of a 5-generational Han Chinese family with CADASIL patients and identified an R133C mutation in the NOTCH3 gene. Clinical analysis demonstrated that the penetrance of the mutation was not complete. Five of the mutation carriers, not exposed to the known vascular risk factors, did not show any clinical feature of CADASIL, suggesting the importance of environmental factors to the development of this disease.ConclusionsMembers of a 5-generational Han Chinese family with CADASIL patients had an R133C mutation in the NOTCH3 gene but only individuals exposed to known vascular risk factors developed CADASIL.