A de novo deletion in X 27-28 spans at least 3 megabases and results in fragile X syndrome
- Duke Univ. Medical Center, Durham, NC (United States)
A 2-year-old boy with Martin-Bell syndrome was referred for molecular testing and found to have a large deletion of FMRI. His mother was found to have two FMR-1 alleles in the normal range for CGG repeats. DNA probes located both proximal and distal to FRAXA were used to delineate the approximation location of the deletion endpoints. Proximal to the fragile site, DXS312 (pX135) was absent but DXS98 (4D8) was present. Distal to the fragile site, DXS296 (VK21) was absent but DXS304 (U6.2) was present. Our patient does not appear to have clinical findings other than those typically associated with fragile X syndrome suggesting that the deletion does not remove other contiguous genes, e.g., IDS. The deletion in this patient is larger than the patient reported by Gedeon et al., in whom approximately 2.5 megabases were estimated to be deleted. Using the physical map of Schlessinger et al., the physical extent of the deletion can be estimated to be at least 3 megabases. This patient may be useful in physical mapping of the chromosomal region near FMR-1. Continued long-term evaluation of this patient may uncover clinical findings suggestive that the deletion removes other genes near to FMR-1 or, alternatively, no findings atypical of the fragile X syndrome suggesting that no other genes lie in the deletion interval.
- OSTI ID:
- 62062
- Journal Information:
- American Journal of Medical Genetics, Vol. 51, Issue 4; Other Information: PBD: 15 Jul 1994
- Country of Publication:
- United States
- Language:
- English
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