Difficulty in differential diagnostics of congenital adrenal hyperplasia – family report
| Authors | |
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| Year of publication | 2007 |
| Type | Article in Proceedings |
| Conference | Sborník abstrakt 22. pracovní dny Dědičné metabolické poruchy |
| MU Faculty or unit | |
| Citation | |
| Field | Genetics and molecular biology |
| Keywords | Congenital adrenal hyperplacia; differential diagnostics; CYP21 gene; MLPA |
| Description | We present here an example of difficulty during DNA analysis in one CAH family and improvement of diagnostics after establishing of the MLPA method and sequencing. The first family member was sent for the molecular examination (carrying status) because the CAH was presented in her aunt and cousin. Test for 11 prevalent mutations was performed. Despite the woman had not any clinical symptoms, we found that she carry point mutation I172N in homozygote state. Consecutively, other family members, including normal and affected ones were examined. Equivocal results were obtained, including the I172N mutation manifested on the mutant allele in mosaic-like form at the rate of approximately 20%:80% and the R356W mutation manifested on the mutant allele in mosaic-like form at the rate of approximately 60%:40%. Using the MLPA technique and sequencing, we identified two types of changes of nucleotide sequence in the annealing place of the 3-primer, which was used for specific amplification of the CYP21 gene. The result is either full or partial or no amplification of CYP21 gene of the given allele. This quantitatively different level of amplification of particular alleles caused false positive result of the I172N/I172N examined women. In the reality, she carry only one gene with the I172N mutation. Her second allele was not amplified. In conclusion, polymorphisms in the annealing place of primers can cause difficulty in molecular diagnostics of CAH. |
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