Homozygous V377I mutation causing mevalonate kinase

Hyperimmunoglobulinaemia D syndrome (HIDS) is a rare autosomal recessive disorder caused by mutations in the mevalonate kinase (MVK) gene, located on chromosome 12. The most common mutation identified in MVK gene so far is V377I. Compound heterozygotes that include this variant may exhibit a more severe phenotype of the disease and homozygotes are rarely found in clinical practice probably they express a milder phenotype. HIDS is a chronic autoinflammatory disease characterised by recurrent febrile episodes, associated with lymphadenopathies, abdominal pain, rash and arthritis. These flares can be triggered by vaccination, minor trauma, surgery and stress.We report a case of a 2-year-old girl who had recurrent attacks of fever associated with cervical lymphadenopathy, macular erythematous skin rash, abdominal pain and aphthous ulcers in the mouth. The patient was found to excrete elevated amounts of urinary mevalonic acid and a homozygous V337I mutation in the MVK gene was identified.