Myopathy and phosphorylase kinase deficiency caused by a mutation in the PHKA1 gene.

Phosphorylase kinase (PhK) deficiency is the underlying cause of variable clinical symptoms depending on the tissues involved. Until today, only a few cases of myopathy associated with muscle PhK deficiency caused by a mutation in the gene encoding the alpha subunit of phosphorylase kinase (PHKA1) have been reported. We describe a male patient with myopathy and absent muscle PhK activity caused by a frameshift mutation in the gene encoding the alpha subunit of PhK on chromosome Xq12-q13.

Moyamoya disease and Down syndrome: case report and review of the literature.

We present the case of a 29-year-old woman with Down syndrome who developed bilateral frontal ischemic stroke. Cerebral angiography demonstrated an occlusion of the both supraclinoid internal carotid arteries associated with dilated collateral vessels, consistent with moyamoya disease. We review the clinical and radiological features of moyamoya disease associated with Down syndrome and discuss a few major physiopathologic hypotheses to explain this association.