Utility of clinical exome sequencing in a complex Emirati pediatric cohort

Clinical exome sequencing (CES) has become a routine diagnostic tool in several pediatric subspecialties, with a reported average diagnostic yield of ~25% in this patient poulation. The utility of CES in the United Arab Emirates (UAE) has not been previously investigated, most likely due to the lack of the appropriate tertiary pediatric centers and diagnostic genomic facilities in this country. Here, we report, for the first time, CES findings on a multispecialty pediatric cohort in the UAE (N = 51). This cohort, which was mostly Emirati (86%; 44/51), was followed at Al Jalila Children's Hospital (AJCH), the first and only dedicated tertiary pediatric center in the country. CES demonstrates a high diagnostic yield (41%; 21/51) in this cohort, where 55% (28/51) had previous non-diagnostic genetic testing while for the remaining individuals (45%), CES was the first-tier test. Given the reported high consanguinity rate in this population, 48% of the positive cases (10/21) were due to genes associated with recessive conditions. However, 11 out of 21 positive cases (52%) were due to heterozygous pathogenic variants in genes known to cause dominantly inherited disorders, including a case with a dual diagnosis attributed to two different genes (2%; 1/51), and another case with a novel de novo variant and new phenotypic features for a known gene (2%; 1/51). Overall, we have identified 13 novel clinically significant variants and showed that application of CES as a first-tier test plays a significant role in genetic diagnosis and management of Emirati pediatric patients.