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Misleading linkage results in an NF2 presymptomatic test owing to mosaicism
- Source :
- Journal of Medical Genetics. 34:934-936
- Publication Year :
- 1997
- Publisher :
- BMJ, 1997.
-
Abstract
- A two generation family with neurofibromatosis type 2 (NF2) is presented in which a family member requested presymptomatic molecular diagnosis. Since the consultand's mother had clinically well defined NF2, he was quoted to be at 50% risk of carrying an NF2 mutation. Mutation screening in the mother did not show the causative mutation and, consequently, presymptomatic testing was based on linkage analysis. This showed that the consultand carried the high risk chromosome 22. Subsequent mutation screening of his clinically affected sister showed a nonsense mutation, R262X in exon 8 of the NF2 gene. The mother turned out to be a mosaic for R262X; the son had not inherited the mutation. Mosaicism may be a common mechanism in NF2 and other autosomal dominant diseases with a high new mutation rate. This may be one explanation for a difference in expression in generations. Caution has to be exercised when giving results based on linkage tests which imply a very high risk to people in the second generation.
- Subjects :
- Adult
Male
Neurofibromatosis 2
Genetic Linkage
DNA Mutational Analysis
Nonsense mutation
Genetic Counseling
Biology
Exon
Predictive Value of Tests
Genetic linkage
otorhinolaryngologic diseases
Genetics
medicine
Humans
Presymptomatic Testing
Genetic Testing
Neurofibromatosis type 2
Polymorphism, Single-Stranded Conformational
Genetics (clinical)
Linkage (software)
Neurofibromin 2
Mosaicism
Nucleic Acid Heteroduplexes
Membrane Proteins
medicine.disease
Mutation (genetic algorithm)
Female
Chromosome 22
Research Article
Subjects
Details
- ISSN :
- 14686244
- Volume :
- 34
- Database :
- OpenAIRE
- Journal :
- Journal of Medical Genetics
- Accession number :
- edsair.doi.dedup.....13758567e46d91e9b0efbfded14a93cb