| Popis: |
We report a case of mosaic trisomy 3 in a one year old boy. He is the .fth child of normal, healthy parents with normal karyotypes. Cytogenetic analysis of blood lymphocytes was done for evaluation of dysmorphic features. Chromosome analysis of blood cells with G - banding showed only 47, XY, +3 karyotype while analysis of skin .broblasts revealed mosaic karyotype - 47, XY, + 3 / 46, XY. Fluorescence in situ hybridization (FISH) analysis using an alpha satellite chromosome 3 probe performed on skin .broblasts demonstrated two signals in 198 nuclei (46, XY) and three signals in 2 nuclei (47, XY, + 3). This result con.rms the diagnosis of low level trisomy 3 mosaicism. The propositus was born after a full term pregnancy. Several dismorphic facial features were noted: caratacts of both eyes, cleft upper right lip and complete cleft of the palate. Heart ultrasound showed ASD secundum. Brain US and CT showed periventricular hypoxia with cystic leucomalatia. Genetic counselling in such a family can be dif.cult. As both parents in the present case had normal karyotypes, the risk seems to be extremely small but it can also be further minimized if the next pregnancy is properly supervised. Additional cases of postnataly diagnosed mosaicism for rare trisomies are necessary for more accurate assessment of the signi.cance of our cytogenetic and clinical findings. |
