Mevalonic Aciduria as a Differential Diagnosis of Blueberry Muffin Baby

Mevalonate kinase (MK) deficiency is an auto inflammatory autosomal recessive disorder caused by a mutation in the gene encoding MK, an essential enzyme in the biosynthesis of cholesterol and isoprenoids. The disease has a wide clinical spectrum according to enzyme residual activity, the most severe form is known as Mevalonic Aciduria (MA). The aim of this article is to report a clinical case of severe MA, with an initial manifestation of a skin rash known as blueberry muffin, most commonly associated with congenital infections or neonatal hematopoietic diseases. We report the case of a three-month boy, born to consanguineous parents, that was referred to our service for assessment of malnutrition, vomiting, fever, jaundice and hepatosplenomegaly. At birth, he presented a purpuric rash suggestive of Blueberry Muffin Baby Syndrome. A thorough investigation revealed increased excretion of urinary mevalonic acid and a single mutation in homozygosis in exon 10 of the MK gene, which confirmed the diagnosis of MA. Our clinical case brings out the first report that associates blueberry muffin rash and MA.