Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, NICU, via della Commenda 12, 20122 Milan, Italy; University of Milan, Department of Clinical Sciences and Community Health, via della Commenda 12, 20122 Milan, Italy. Electronic address: [Email]
Systemic inflammation in neonates is attributable to an infection in almost all cases. When inflammation persists, an autoinflammatory disease should be promptly suspected. We report here a case of mevalonate kinase deficiency (MKD) that presented at birth with mild symptoms and signs suggestive for a perinatal infection, together with the uncommon finding of interstitial lung disease. An extensive diagnostic work-up, performed after ineffective antibiotic treatment, demonstrated high levels of mevalonic acid in urine (7024 mM/M of creatinine, normal value <0.1). Next-generation sequencing showed a rare c.709A > T (p.T237S) homozygous mutation in the MVK gene, consistent with MKD. Treatment with anakinra led to a prompt resolution of symptoms and a sharp drop in serum inflammatory markers. The patient is now six months-old, currently undergoing evaluation for hematopoietic stem-cell transplantation. To our knowledge, this is the first case of MKD presenting within the first week of life with interstitial lung disease.