An Atypical Presentation of Mevalonate Kinase Deficiency in Response to Colchicine Treatment.

Mevalonate kinase deficiency (MKD) is a periodic fever syndrome. Nonsteroidal anti-inflammatory drugs, corticosteroids, and anakinra are the most common treatments. However, colchicine is considered insufficient in disease control. In this case report, we present an 8-month-old infant with an atypical presentation of MKD. She had recurrent fever episodes, diarrhea, and lethargy. Elevated mevalonic acid was not detected in the urine. However, the genetic investigation showed a novel pathogenic heterozygous c.925G>C (p.Gly309Arg) variant and a heterozygous c.1129G>A (p.Val377Ile) mutation in the MVK gene. The patient was treated with colchicine for 8 months. During treatment, no further fever episode had been observed. It should be kept in mind that mevalonic acid excretion may not be present in the urine with mild MKD. Colchicine may be a reasonable option in mild MKD patients for a longer duration of treatment due to favorable adverse event profiles.