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Summary: A patient with partial chromosome I2q duplication and lOq deletion: Chromosomal deletions and/or duplications are relatively common cytogenetic abnormalities. Clinical findings depend on pure or complex forms of the anomaly, the location and size. In those cases, using current analytical technologies increases the possibility of discovering candidate genes that were not detected by conventional karyotyping responsible for these features. Here, we report an 18-month-old girl with prenatal and postnatal growth retardation, secundum ASD and PDA, facial dysmorphic features including frontal bossing, arched eyebrows, hypertelorism, wide nasal bridge and chronic diarrhea. Chromosome analysis on the peripheral leukocytes showed a 46,XX del(10)(q26.3),dup(12Xq24.1 l-q24.33) dn karyotype. An array-CGH analysis was performed to understand which genes were located on the deletion and duplication regions and what was their relationship with the phenotype. Based on our analyses, the deletion of the CALY gene on Chromosome 1 Oq and the duplication of PTPN11 and TBX5 genes on chromosome 12q were possibly relevant for the clinical findings with our patient.
Key-words: Mental retardation - Array CGH - Genotype-phenotype correlation.
INTRODUCTION
The distal lOq deletion is a relatively common cytogenetic abnormality. The studies about the partial deletion of the long arm of chromosome 10 indicated that the breakpoints are usually seen at the 10q23.310q26.3 chromosomal region (5). Distinctive features of the distal lOq deletion include specific facial features, neurodevelopmental defects and cardiac anomalies (9).
The genotype-phenotype correlations in the previous studies may not be reliable due to the standard conventional methods (GTG-banding, FISH analyses). However, new molecular methods including array comparative genomic hybridization (array-CGH) and single nucleotide polymorphism (SNP) analyses are able to describe the genes in the deleted or duplicated regions (8). Recently, Yatsenko et al. (12) and Plaisancie et al. (6) detected minimal critical regions and the most likely responsible genes for the partial chromosome lOq deletion syndrome by using new techniques. The smallest region of overlap (SRO) in all patients was 600 kb segments, which contained DOCK1 and C100RF90 genes as the candidate genes (12). Learning difficulties, a triangular face, prominent nose, developmental delay, and hip dislocation were the common characteristics of patients with the deletion covering SRO (6,12)
The duplication of the 12q terminal region is a more rare condition as compared to the distal lOq...