Familiální výskyt balancované a nebalancované formy translokace t(1;12) v rodině se dvěma postižnými dětmi
| Title in English | Segregation of balanced and unbalanced translocation t(1;12)(p36;q24) in a family with two affected children |
|---|---|
| Authors | |
| Year of publication | 2011 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | We report a familial inheritance of a translocation t(1;12) in its balanced and unbalanced version, segregating in two generations. Two healthy adult sisters have a balanced translocation t(1;12)(p36;q24) (Mother 1), and an unbalanced translocation dup(1)(p36) del(12)(q24) (Mother 2), respectively. Mother 1 has a daughter (Patient 1) displaying moderate MR, discrete facial dysmorphism and delayed motor development associated with an unbalanced translocation del(1)(p36)dup(12)(q24). Mother 2 has a son (Patient 2) with mild mental retardation, delayed expressive language and dysmorphic features, which has inherited the same unbalanced translocation dup(1)(p36) del(12)(q24) from his mother. The deletion on 1p36 is assumed to be causative for the Patient's 1 phenotype, whereas the duplication on 12q24 has not probably an effect on the phenotype, because of its small size and its location in region of frequent polymorphism. Microdeletion 1p36 is the most common terminal deletion syndrome, described at 1:5000 births. The aberrant phenotype in Patient 2 could be caused by reciprocal duplication in the same region on 1p36; however it is inherited from his phenotypically normal mother. In the available databases (Decipher, Ecaruca), there are described 4 patients with mental retardation or developmental delay causing by duplication on 1p36 (from them: 1 case has inherited duplication 1p36 from normal parent, 1 case with de novo duplication, and in 2 cases the origin was unknown). Currently it is not enough information available to conclude if the duplication of 1p36 might cause a syndrome characterized by reduced penetrance or if the clinical phenotype of Patient 2 has another etiology. We used the array-CGH 1x244K (Agilent Technologies) for specification of all findings and for determination of the aberration’s size: there was duplication/deletion in size of 1,88Mb on 1p36.32 and duplication/deletion in size of 95kb on 12q24.32. In case of relatively small changes on 12q24.32, we had to use combination of all available molecular-cytogenetic methods for final determination of possible breakpoints, and for explanation of so far discrepant results by MLPA, FISH and array-CGH 4x44K. |
| Related projects: |