Recurrance of sporadic neurofibromatosis type 1 due to germline mosaicism in the unaffected father
- Institut de Recerca Oncologica, Barcelona (Spain); and others
Neurofibromatosis type 1 (NF1) or von Recklinghausen disease is one of the most common autosomal dominant disorders in man. In this report we describe a kindred with two affected offspring, in which neither of the parents fulfills the diagnostic criteria of NF1. DNA from peripheral blood was obtained from the family members and from the father`s spermatozoa. Several microsatellite markers, located in intronic regions of the NF1 gene, NF1 cDNA probes, and individual NF1 exons, were analyzed. NF1 microsatellite analysis in the family showed that there was no inheritance of paternal alleles for marker IVS38GT53.0 in the two affected siblings, while they inherited alleles from both parents for other intragenic markers. Hybridization of DNA from the family members with intragenic probes detected abnormal fragments in the lymphocytes from the NF1 individuals and in 10% of father`s spermatozoa, but not in lymphocytes from the parents. The restriction map was consistent with an interstitial deletion of 12 kb. So, we have detected hemizygosity for a microsatellite marker within the NF1 gene, and demonstrated that severe NF1 in a family with recurrence of the diseas, is due to the inheritance of a 12-kb deletion from the clinically unaffected father, who is mosaic for the deletion in his germline cells. This is the first time that germline mosaicism has been demonstrated in NF1. The analysis of the specific NF1 mutation in the sperm of the parent in de novo cases might help in the detection of mosaicism, facilitating genetic counseling.
- OSTI ID:
- 134245
- Report Number(s):
- CONF-941009--
- Journal Information:
- American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
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