Abstract
The fragile X syndrome is characterized by X-linked mental retardation with additional features such as a long face with large protruding ears, macroorchidism, and eye-gaze avoidance. The disorder is caused by an abnormally expanded CGG repeat within the first exon of the fragile X mental retardation (FMR1) gene that is associated with shutdown of transcription and absence of the fragile X mental retardation protein (FMRP). Detection of patients and carriers of the fragile X syndrome is done by DNA analysis of the CGG repeat, whereas the FMRP antibody test allows rapid detection of male patients using bloodsmears. In a screening program for the fragile X syndrome in the southwest of the Netherlands, 412 males with mental retardation of unknown cause were subjected to the protein test. The patients were scored for fragile X features and their DNA tested for the FMR1 mutation, as reported previously. The FMRP test detected two fragile X patients with a repeat expansion in FMR1, whereas normal protein expression was observed in all the retarded male patients with a normal repeat. The FMRP test was found to be suitable for screening among a large population of retarded males. The results also suggest that mutations other than the CGG repeat leading to absence of detectable FMRP are apparently rare among mentally retarded males.
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Received: 22 April 1998 / Accepted: 5 June 1998
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de Vries, B., Mohkamsing, S., van den Ouweland, A. et al. Screening with the FMR1 protein test among mentally retarded males. Hum Genet 103, 520–522 (1998). https://doi.org/10.1007/s004390050860
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DOI: https://doi.org/10.1007/s004390050860