The genomic landscape of rare disorders in the Middle East.

BACKGROUND: Rare diseases collectively impose a significant burden on healthcare systems, especially in underserved regions, like the Middle East, which lack access to genomic diagnostic services and the associated personalized management plans. METHODS: We established a clinical genomics and genetic counseling facility, within a multidisciplinary tertiary pediatric center, in the United Arab Emirates to locally diagnose and manage patients with rare diseases. Clinical genomic investigations included exome-based sequencing, chromosomal microarrays, and/or targeted testing. We assessed the diagnostic yield and implications for clinical management among this population. Variables were compared using the Fisher exact test. Tests were 2-tailed, and P < .05 was considered statistically significant. RESULTS: We present data on 1000 patients with rare diseases (46.2% females; average age, 4.6 years) representing 47 countries primarily from the Arabian Peninsula, the Levant, Africa, and Asia. The cumulative diagnostic yield was 32.5% (95% CI, 29.7-35.5%) and was higher for genomic sequencing-based testing than chromosomal microarrays (37.9% versus 17.2%, P = 0.0001) across all indications, consistent with the higher burden of single gene disorders. Of the 221 Mendelian disorders identified in this cohort, the majority (N = 184) were encountered only once, and those with recessive inheritance accounted for ~ 62% of sequencing diagnoses. Of patients with positive genetic findings (N = 325), 67.7% were less than 5 years of age, and 60% were offered modified management and/or intervention plans. Interestingly, 24% of patients with positive genetic findings received delayed diagnoses (average age, 12.4 years; range 7-37 years), most likely due to a lack of access to genomic investigations in this region. One such genetic finding ended a 15-year-long diagnostic odyssey, leading to a life-threatening diagnosis in one patient, who was then successfully treated using an experimental allogenic bone marrow transplant. Finally, we present cases with candidate genes within regions of homozygosity, likely underlying novel recessive disorders. CONCLUSIONS: Early access to genomic diagnostics for patients with suspected rare disorders in the Middle East is likely to improve clinical outcomes while driving gene discovery in this genetically underrepresented population.

Rapid whole genome sequencing of critically ill pediatric patients from genetically underrepresented populations.

We describe a case series of five infants (age range: 1-90 days; 4 females and 1 male) who presented to Al Jalila Children's intensive care units (ICU) with complex multisystem disorders. Patients were Emirati, Kenyan, Jordanian, Filipino, or Pakistani. Trio rapid whole genome sequencing (rWGS) was performed on all five patients and their parents within the hospital's genomics facility. Results were returned within ~37 h from blood sample draws and were diagnostic in 3 out of 5 patients. Positive findings were a homozygous pathogenic variant in POMT1 gene causing muscular dystrophydystroglycanopathy, a mosaic tetrasomy of the short arm of chromosome 12 (12p13.33p11.1) causing Pallister-Killian syndrome, and compound heterozygous pathogenic variants in the LIPA gene causing lysosomal acid lipase deficiency and Wolman disease. The rWGS analysis provided fast and precise diagnostic findings in those 3 patients and also aided in devising better management plans for them in the intensive care setting. For example, the 3-month-old infant with pathogenic variants in the LIPA gene is now a candidate for an FDA-approved, potentially lifesaving enzyme replacement therapy (sebelipase alfa). Our case series emphasize the feasibility and utility of rWGS in pediatric intensive care setting, in a diverse population that has long been underserved in genomic services. Significant investments in local healthcare infrastructure are needed, globally, for more equitable access of genomic medicine among vulnerable patients.