Le déficit en mévalonate kinase en 2016

Efficacy of Anakinra Treatment in two Moroccan Patients With Mevalonate Kinase Deficiency

Mevalonate kinase deficiency (MKD) is a rare hereditary autoinflammatory disease, with a widely variable clinical spectrum. It is characterized by febrile recurrent episodes and systemic inflammation. Data on therapeutic options for MKD are still limited and remain unknown in our country. We report Moroccan cases with MKD referred in our unit and treated with Anakinra, an interleukin-1 receptor antagonist. Through this study, we evaluate the efficacy of this bioagent, in our 2 MKD patients, in whom Anakinra has shown a complete clinical remission, with a remaining mild inflammation for one case, and normalization of growth with rare episodes of cervical adenopathies for the second case. Our experience provides an additional argument supporting the efficacy of Anakinra treatment, demonstrated previously but still lacks of objective data.

Spectrum of auto-inflammatory diseases in Morocco: a monocentric experience

Objective

Auto-inflammatory diseases (AIDs) result from mutations in genes of the innate immune system leading to periodic multisystemic inflammation. We aimed to describe the clinical, biological and molecular features (when available) and outcomes of Moroccan patients with AIDs.

Methods

Patient data were collected retrospectively and analysed over a 13-year period.

Results

Among 30 patients, 60% had FMF, 16% mevalonate kinase deficiency (MKD) and 24% other AIDs. The mean age at first consultation was 6.9 years, and the mean diagnostic delay was 3 years. Consanguinity was reported in 16 cases. IgA vasculitis was associated with 33% of FMF patients, in whom the main clinical features were fever (88.8%), abdominal pain (100%), arthralgias (88.8%) and arthritis (50%), and the most frequent mutation was M694V (66%). All FMF patients were treated with colchicine. Most MKD patients were confirmed by elevated urinary mevalonic acid levels, and four of five MKD patients received targeted therapy. Chronic recurrent osteomyelitis patients were confirmed by radiological and histological analysis. Two cases of Marshall syndrome were diagnosed according to validated criteria. A case of familial pustular psoriasis was diagnosed based on histological analysis and a patient with Muckle-Wells syndrome by clinical features. The outcome was favourable in 76%, partial in 13%, and three deaths were reported.

Conclusion

FMF and MKD are the most reported diseases. AIDs are probably underestimated because they are unknown to clinicians. The aim of this work is to raise awareness among paediatricians about AIDs and create a network for best practice.

Twists and turns of the genetic story of mevalonate kinase-associated diseases: A review

Mevalonate kinase (MK)-associated diseases encompass a broad spectrum of rare auto-inflammatory conditions, all resulting from pathogenic variants in the mevalonate kinase gene (MVK). Their clinical manifestations are highly variable, ranging from more or less serious systemic disorders, such as hereditary recurrent fevers, to purely localized pathologies such as porokeratosis. The oldest condition identified as linked to this gene is a metabolic disease called mevalonic aciduria, and the most recent is disseminated superficial actinic porokeratosis, a disease limited to the skin. The modes of inheritance of MK-associated diseases also diverge among the different subtypes: recessive for the systemic subtypes and dominant with a post-zygotic somatic genetic alteration for MVK-associated porokeratosis. This review quickly retraces the historical steps that led to the description of the various MK-associated disease phenotypes and to a better understanding of their pathophysiology, then summarizes and compares the different genetic mechanisms involved in this group of disorders, and finally discusses the diverse causes that could underlie this phenotypic heterogeneity.

Cutaneous clues to diagnose autoinflammatory diseases

Systemic autoinflammatory diseases (AIDs) are a group of disorders characterized by recurrent episodes of systemic inflammation. Suspecting the diagnosis can be difficult and many of the clinical manifestations are common to different diseases. Although most of the cutaneous manifestations are non-specific, it is important to know them because sometimes they can lead to the diagnosis. The purpose of this review was to synthesize the main cutaneous lesions of autoinflammatory diseases to aid in their diagnosis.

Autoinflammatory diseases: State of the art

Autoinflammatory diseases are characterized by innate immunity abnormalities. In autoinflammatory diseases (AID), inflammatory blood biomarkers are elevated during crisis without infection and usually without autoantibodies. The first 4 described AID were familial Mediterranean fever, cryopyrin-associated periodic fever syndrome (CAPS) or NLRP3-associated autoinflammatory disease (NRLP3-AID), mevalonate kinase deficiency (MKD) and TNFRSF1A-receptor associated periodic fever syndrome (TRAPS). Since their description 20 years ago, and with the progresses of genetic analysis, many new diseases have been discovered; some with recurrent fever, others with predominant cutaneous symptoms or even immune deficiency. After describing the 4 historical recurrent fevers, some polygenic inflammatory diseases will also be shortly described such as Still disease and periodic fever with adenitis, pharyngitis and aphtous (PFAPA) syndrome. To better explore AID, some key anamnesis features are crucial such as the family tree, the age at onset, crisis length and organs involved in the clinical symptoms. An acute phase response is mandatory in crisis.

[Clinical overview of auto-inflammatory diseases]

Monogenic auto-inflammatory diseases are characterized by genetic abnormalities coding for proteins involved in innate immunity. They were initially described in mirror with auto-immune diseases because of the absence of circulating autoantibodies. Their main feature is the presence of peripheral blood inflammation in crisis without infection. The best-known auto-inflammatory diseases are mediated by interleukines that consisted in the 4 following diseases familial Mediterranean fever, cryopyrinopathies, TNFRSF1A-related intermittent fever, and mevalonate kinase deficiency. Since 10 years, many other diseases have been discovered, especially thanks to the progress in genetics. In this review, we propose the actual panorama of the main known auto-inflammatory diseases. Some of them are recurrent fevers with crisis and remission; some others evaluate more chronically; some are associated with immunodeficiency. From a physiopathological point of view, we can separate diseases mediated by interleukine-1 and diseases mediated by interferon. Then some polygenic inflammatory diseases will be shortly described: Still disease, Schnitzler syndrome, aseptic abscesses syndrome. The diagnosis of auto-inflammatory disease is largely based on anamnesis, the presence of peripheral inflammation during attacks and genetic analysis, which are more and more performant.