Inherited Unbalanced Chromosome from Parent with Balanced Translocation

Reciprocal translocations are common, and the translocation heterozygote (carrier) may have a child who is mentally and physically abnormal as a result of a segmental aneusomy. The carriers of balanced translocation mostly do not have recognizable phenotypic expression, however, they can produce unbalanced chromosome, which is passed down to the next generation via fertilisation of gametes carrying the derivative chromosome. We present the case of a 4-year-old boy with partial 10q trisomy and distal 13qmonosomy. The patient had delayed milestones, a dysmorphic face, a congenital heart defect, renal and skeletal anomalies. The conventional cytogenetic analysis showed a 46,XY, add(13q) karyotype. The child inherited the unbalanced chromosome from mother who was a carrier of balanced reciprocal translocation, t(10;13)(p24.2;q33.1). The phenotype observed in our patient was caused by a combination of defects described in the isolated dup(10q) and distal del(13q) syndromes, but it primarily resembles children with distal trisomy 10q syndrome. Our findings are consistent with previous research and support the importance of critical regions such as 10q24 and 13q32 in the phenotypic expression of distal 10q trisomy syndrome and distal 13q trisomy syndrome, respectively. There is a need to create awareness regarding such chromosomal imbalances and its consequences among general practitioners and relatives for better management of chromosomally unbalanced child.