A Distinct Phenotype of Mevalonic Acidemia with Absence of Pathogenic Mutations of Mevalonate Kinase Gene نمط ظاھري متميز لبيلة الميفالونيك مصاحبه بعدم وجود طفرات مرضيه في جين ميفالونات كيناز

Mevalonic aciduria is an autosomal recessive disorder caused by deficiency of mevalonate kinase and characterized by recurrent febrile crisis, ophthalmic and neurological manifestations. We report two brothers with mevalonic aciduria characterized clinically by severe failure to thrive, psychomotor retardation, dysmorphic features, retinitis pigmentosa and hypoplastic genitalia. Recurrent episodes of fever, a characteristic feature of mevalonic aciduria due to deficiency of mevalonate kinase enzyme was absent. Both patients excreted moderate amounts of mevalonic acid. Molecular analysis of MVK gene showed no abnormalities and plasma 7-dehydrocholesterol and serum immunoglobulin D were normal. This phenotype-genotype association has not been described in previous reports and future molecular genetic studies are required to know the full spectrum of disorders of the mevalonate pathway.