BACKGROUND Rare diseases collectively impose 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 counselling 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. RESULTS We present data on 529 patients with rare diseases (47% females; Average age, 4 years) representing 41 countries primarily from the Arabian Peninsula, the Levant, Africa, and Asia. The cumulative diagnostic yield was 35.7% (95% CI, 31.8% - 39.9%) and was higher for genomic sequencing-based testing than chromosomal microarrays (41.2% versus 16.9%, P=0.0001) across all indications, consistent with the higher burden of single gene disorders. Of the 124 Mendelian disorders identified in this cohort, the majority (N = 110) were encountered only once, and those with recessive inheritance accounted for ~60% of sequencing diagnoses. Of patients with positive genetic findings (N = 189), 71.9% were less than 5 years of age, and 65.6% were offered modified management and/or intervention plans. Interestingly, 18.5% of patients with positive genetic findings received delayed diagnoses (age range 7 to 37 years), most likely due to 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 historically underrepresented population.

The authors have declared no competing interest.

This study did not receive any funding

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The Ethics committee of Dubai Healthcare Authority gave ethical approval of this work (AJCH 44).

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.

Yes

All data produced in the present work are contained in the manuscript