Background
The 22q13.3 deletion syndrome is a rare autosomal aberration with a wide phenotypic spectrum. Overall, 20% of the cases result from ring chromosome 22 [r(22)] or unbalanced translocation disrupting the 22q13 region. Up to 2013, only 60 cases with r(22) have been reported.
Patients and methods
Two unrelated Egyptian female patients of consanguineous parents presented with profound developmental delay, absent speech, microcephaly, seizures, and autistic behavior and were subjected to comprehensive clinical and orodental examination and imaging studies. Conventional cytogenetic analysis was done for the patients and their parents, and fluorescence in-situ hybridization analysis was performed for both patients.
Results
Karyotyping showed a r(22) abnormality in the two patients and normal chromosomes in the parents. Fluorescence in-situ hybridization revealed deletion of 22q13.3 and 22q subtelomere in both patients.
Conclusion
Our patients add to the previously reported rare cases of r(22). 22q13.3 terminal deletion should be considered in cases of intellectual disability and delayed speech associated with seizures and autistic behavior, even in consanguineous mating.