Avoid common mistakes on your manuscript.
Dear Editors,
In the recently published article entitled “A rare cause of AA amyloidosis and end-stage kidney failure,” Tașdemir et al. present a case of AA amyloidosis attributed to hypergammaglobulinemia D syndrome (HIDS), renamed mevalonate kinase deficiency (MKD) [1], in a 14-year-old girl with an unusual clinical presentation. The authors concluded to the diagnosis of MKD based on clinical findings, persistently elevated serum IgD level, and the presence of a single heterozygous mutation in the mevalonate kinase (MVK) gene. However, we wonder if a diagnosis of MKD can be retained in this case.
Indeed, MKD is a rare autosomal recessive autoinflammatory disease associated with homozygous or double heterozygous pathogenic mutations in the MVK gene, yet the patient here carries only one MVK variant, whose pathogenicity has not been reported in the literature according to the Infevers registry. Furthermore, the authors did not specify the gene sequencing technique used, namely next-generation (NGS) or Sanger sequencing, which can influence the results of the genetic analysis.
Biologically, elevated serum IgD levels are not specific to MKD. It has previously been described in other hereditary autoinflammatory disorders like familial Mediterranean fever (FMF), tumor necrosis factor receptor–associated periodic syndrome (TRAPS), and cryopyrin-associated periodic syndrome (CAPS). Conversely, serum IgD level can be normal in MKD [2]. The urinary mevalonic acid level was not reported by the authors; an elevation of this marker would have been an additional argument for a diagnosis of MKD.
Finally, the clinical features of the patient in this paper are unusual for MKD. This disease usually causes recurrent febrile attacks with abdominal pain, arthralgia, lymphadenopathy, and various skin lesions starting before the first year of life. It rarely leads to AA amyloidosis; when it does, the latter develops in adulthood after several years of evolution of a chronic inflammatory syndrome [3].
Altogether, it seems unlikely that this patient was suffering from MKD. The spectacular efficacy of anti-IL-1β antibodies is in favor of an inflammasomopathy, but not specifically of MKD. We believe that an analysis by NGS of the main genes involved in monogenic autoinflammatory diseases would allow to refine the final diagnosis.
References
Ben-Chetrit E, Gattorno M, Gul A, Kastner DL, Lachmann HJ, Touitou I et al (2018) Consensus proposal for taxonomy and definition of the autoinflammatory diseases (AIDs): a Delphi study. Ann Rheum Dis 77(11):1558–1565
Ter Haar NM, Jeyaratnam J, Lachmann HJ, Simon A, Brogan PA, Doglio M et al (2016) The phenotype and genotype of mevalonate kinase deficiency: a series of 114 cases from the Eurofever registry. Arthritis Rheumatol 68(11):2795–2805
van der Hilst JCH, Bodar EJ, Barron KS, Frenkel J, Drenth JPH, van der Meer JWM et al (2008) Long-term follow-up, clinical features, and quality of life in a series of 103 patients with hyperimmunoglobulinemia D syndrome. Medicine (Baltimore) 87(6):301–310
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Galland, J., Savey, L. Comments on Tașdemir et al.: A rare cause of AA amyloidosis and end-stage kidney failure. Pediatr Nephrol 34, 1635 (2019). https://doi.org/10.1007/s00467-019-04278-8
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00467-019-04278-8