• Patrick Santens, Tim Van Damme, Wouter Steyaert, Andy Willaert, Bernard Sablonnière, Anne De Paepe, Paul J Coucke, and Bart Dermaut.
• From the Department of Neurology (P.S., B.D.) and the Center for Medical Genetics (T.V.D., W.S., A.W., A.D.P., P.J.C., B.D.), Ghent University Hospital, Belgium; and Inserm U1172, Centre de Recherches J-P Aubert (B.S.), and Inserm U1167, Institut Pasteur de Lille (B.D.), Université de Lille, France.
• Neurology. 2015 Apr 28; 84 (17): 1760-6.

ObjectiveTo identify the genetic cause in 2 Belgian families with autosomal recessive Huntington-like disorder (HDL).MethodsHomozygosity mapping and whole-exome sequencing in a consanguineous family as well as Sanger sequencing of the candidate gene in an independent family with HDL followed by genotype-phenotype correlation studies.ResultsWe identified a homozygous mutation in the gene RNF216 p.(Gly456Glu) within a shared 4.8-Mb homozygous region at 7p22.3 in 2 affected siblings of a consanguineous HDL family. In an independent family, 2 siblings with HDL were compound heterozygous for mutations in RNF216 p.(Gln302*) and p.(Tyr539Cys). Chorea, behavioral problems, and severe dementia were the core clinical signs in all patients. Brain imaging consistently showed white matter lesions. Low gonadotropin serum levels and cerebellar atrophy could be demonstrated in the index family.ConclusionsMutations in RNF216 have recently been found in families with Gordon Holmes syndrome, a condition defined by hypogonadotropic hypogonadism and cerebellar ataxia. The mode of inheritance was proposed to be oligogenic for most families. We describe novel RNF216 mutations causing an HDL phenotype with pure monogenic recessive inheritance. Subclinical serum evidence of hypogonadotropic hypogonadism links this disorder to Gordon Holmes syndrome. Our study thus challenges the oligogenic inheritance model and emphasizes chorea as an essential clinical feature in RNF216-mediated neurodegeneration.© 2015 American Academy of Neurology.

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