The importance of using fluorescence in situ hybridization for the diagnosis of Smith-Magenis syndrome
- Baylor College of Medicine, Houston, TX (United States); and others
Smith-Magenis syndrome (SMS) is a clinically recognizable multiple congenital anomaly/mental retardation syndrome associated with deletion of chromosome 17p11.2. Quality metaphase preparations are required for unambiguous detection of the deletion. We and others have reported cases of SMS due to mosaicism for del(17)(p11.2). Examination of peripheral blood lymphocyte cultures of a patient with the SMS phenotype at 850 band level of resolution revealed a low level mosaicism (11%) for the deletion. Examination of fibroblasts at relatively low resolution revealed the deletion in all cells. In a second study, we reported molecular evidence for mosaicism in the unaffected mother of an SMS patient who demonstrated mosaicism (55%) for the deletion at a resolution level of < 500 bands. We now report a different SMS patient who was initially diagnosed as mosaic del(17)(p11.2) in two different cytogenetic laboratories. A third blinded cytogenetic study yielded a questionable diagnosis. Fluorescence in situ hybridization (FISH) conducted in two different laboratories with two different markers shown to be within the deletion region and a control marker from chromosome 17 demonstrated a deletion in 20/20 and 25/25 metaphases scored, respectively. It appears the latter patient may harbor a very small deletion and that FISH is a more reliable test for the Smith-Magenis deletion. Furthermore, FISH should be used to confirm or refute mosaicism seen in routine cytogenetics studies.
- OSTI ID:
- 133702
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-0433
- Journal Information:
- American Journal of Human Genetics, Vol. 55, Issue Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
Similar Records
Apparent mosaicism for del(17)(p11.2) ruled out by fluorescence in situ hybridization in a Smith-Magenis syndrome patient
Molecular analyses of 17p11.2 deletions in 62 Smith-Magenis syndrome patients