Fragile X-associated tremor/ataxia phenotype in a male carrier of unmethylated full mutation in the FMR1 gene

Abstract

Loesch DZ, Sherwell S, Kinsella G, Tassone F, Taylor A, Amor D, Sung S, Evans A. Fragile X-associated tremor/ataxia phenotype in a male carrier of unmethylated full mutation in the FMR1 gene. The Fragile X syndrome is caused by a CGG repeat expansion >200 in the promoter of the Fragile X mental retardation 1 (FMR1) gene termed full mutation (FM). These alleles are silenced through methylation of the FMR1 promoter, leading to deficit of the FMR1 protein (FMRP), and neurodevelopmental changes. However, occasional FM individuals have a complete lack of methylation, and those typically have only minor deficit of FMRP levels compared with normal controls and their intelligence may be in the norma..