Respiratory chain inhibition: one more feature to propose MPTP intoxication as a Leigh syndrome model.

1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxicated mice have been widely used to model the loss of dopaminergic neurons. As this treatment leads to basal ganglia degeneration, it was proposed that MPTP mice could be used as a model of Leigh syndrome. However, this mitochondrial pathology is biochemically characterized by a respiratory chain dysfunction. To determine if MPTP can affect in vivo mitochondria function, we measured the activities of mitochondrial respiratory chain complexes in several tissues. Our results show that MPTP affects mainly mitochondrial respiratory chain complex IV, as found in Leigh Syndrome, confirming that acute MPTP intoxicated mice are a good model of Leigh Syndrome.

Hemiplegic Migraine Associated With PRRT2 Variations: A Clinical and Genetic Study.

BACKGROUND AND OBJECTIVE: PRRT2 variants have been reported in a few cases of patients with hemiplegic migraine. To clarify the role of PRRT2 in familial hemiplegic migraine, we studied this gene in a large cohort of affected probands. METHODS: PRRT2 was analyzed in 860 probands with hemiplegic migraine, and PRRT2 variations were identified in 30 probands. Genotyping of relatives identified a total of 49 persons with variations whose clinical manifestations were detailed. RESULTS: PRRT2 variations were found in 12 of 163 probands who previously tested negative for CACNA1A, ATP1A2, and SCN1A variations and in 18 of 697 consecutive probands screened simultaneously on the 4 genes. In this second group, pathogenic variants were found in 105 individuals, mostly in ATP1A2 (42%), followed by CACNA1A (26%), PRRT2 (17%), and SCN1A (15%). The PRRT2 variations included 7 distinct variants, 5 of which have already been described in persons with paroxysmal kinesigenic dyskinesia and 2 new variants. Eight probands had a deletion of the whole PRRT2 gene. Among the 49 patients with variations in PRRT2, 26 had pure hemiplegic migraine and 16 had hemiplegic migraine associated with another manifestation: epilepsy (8), learning disabilities (5), hypersomnia (4), or abnormal movement (3). Three patients had epilepsy without migraine: 2 had paroxysmal kinesigenic dyskinesia without migraine, and 1 was asymptomatic. DISCUSSION: PRRT2 should be regarded as the fourth autosomal dominant gene for hemiplegic migraine and screened in any affected patient, together with the 3 other main genes. Further studies are needed to understand how the same loss-of-function PRRT2 variations can lead to a wide range of neurologic phenotypes, including paroxysmal movement disorder, epilepsy, learning disabilities, sleep disorder, and hemiplegic migraine.