Clinical presentation and natural history of RAVINE leukoencephalopathy in Reunion Island

RAVINE leukoencephalopathy (RLE) is a hereditary autosomal recessive disease characterized by typical clinical and radiological signs that has so far been observed only in patients of Reunionese origin. The term RAVINE is a French acronym for the main clinical features of the disease: Réunion, Anorexie, Vomissements Incoercibles, signes NEurologiques (Reunion, Anorexia, Intractable Vomiting, NEurological signs). Patients with RLE carry the IVS1-1778A>G mutation of the SLC7A2 gene in the homozygous state. Here we present the first complete clinical description and natural history of RLE.

The medical records of all patients born to Reunionese parents and presenting with suspected RLE were reviewed. The diagnosis of RLE was confirmed by detection of the homozygous mutation IVS1-1178A>G of the SLC7A2 gene. The clinical and paraclinical data of patients with genetically confirmed RLE were retrospectively analyzed to determine the clinical presentation and natural history of the disease.

Our retrospective analysis of the clinical and paraclinical data of 40 patients with genetically confirmed RLE distinguished 3 types of the disease based on the evolution of symptoms. Symptoms were classified into 4 stages of development: stage A, or digestive-like stage, characterized by digestive symptoms and to a lesser extent by neurological symptoms; stage B, or clinically latent stage; stage C, or exacerbation stage, marked by attacks of neurological symptoms; and stage D, or decline stage, characterized by loss of walking ability and progression towards death. Patients with type I RLE (37.5%), or monophasic RLE, experience only the severe stage A. Death occurs before the age of 28months in a very narrow time window (23.0±2.2months). Patients with type II RLE (16.7%), or biphasic RLE, move directly from stage A to stage D. Patients with type III RLE (45.8%), or multiphasic RLE, experience all 4 stages with varying degrees of symptom severity. This is the most frequent type of RLE. The joint occurrence of central apnea and vocal cord paralysis during stage A is indicative of unfavorable prognosis. Corticosteroid therapy seems to be effective during stage A and in some cases during stage C.

This retrospective study provides the first complete clinical description and natural history of RLE. Three types of the disease were distinguished based on the evolution of symptoms. The diagnosis of RLE can be established outside of Reunion Island as many Reunionese couples have emigrated to other parts of the world.