NEW YORK – A team led by investigators in the United Arab Emirates has demonstrated the potential for using genomics-based approaches to diagnose rare diseases in individuals from diverse Middle Eastern populations, prompting a call for increased access to such tests.
"Despite the utility of genomic testing in our setting, this service is largely inaccessible to patients in the region due to the lack of specialized centers with local genomic services," senior and corresponding author Ahmad Abou Tayoun, director of the Al Jalila Genomics Center at Al Jalila Children's Specialty Hospital in Dubai, and his colleagues wrote in Genome Medicine on Friday.
The team presented findings from 1,000 rare disease patients — including 373 non-Emirati individuals — that were profiled at a clinical genomics and genetic counseling center established at Al Jalila Children's, a multidisciplinary tertiary pediatric hospital in the United Arab Emirates.
"Unlike previous studies which focused on specific homogeneous populations (mainly Saudis and Qataris) from this region, our center is located within Dubai, a regionally accessible city with high population diversity, which enabled us to recruit, genetically diagnose, and care for patients with rare diseases from underserved populations, representing at least 41 countries of the Middle East, Africa, and Asia, which have historically been underrepresented in genetic studies," the authors explained.
With the help of exome sequencing, chromosomal microarrays, and other targeted genomic testing strategies, the researchers diagnosed nearly 33 percent of the rare disease cases. The diagnostic yield climbed to 38 percent for cases characterized by genomic sequencing, whereas chromosomal microarrays led to diagnoses in just over 17 percent of cases.
Diagnoses were particularly common in younger individuals, the researchers reported, with just shy of 68 percent of genetic findings occurring in patients under 5 years old. Even so, close to a quarter of the newly diagnosed individuals were between 7 and 37 years old — a result that the investigators attributed to limited genomic testing access. Moreover, genetic diagnoses prompted changes in patient treatment or management around 60 percent of the time.
Together, these and other findings from the study suggested that "[e]arly 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," the authors wrote.
The team's analyses unearthed 221 different Mendelian conditions, including 184 diseases found in just one patient each. Roughly 62 percent of the conditions appeared to involve autosomal recessive inheritance.
Although public healthcare is available to citizens of the UAE, the team noted that genomic testing is often not available through private health insurance for non-Emirati individuals. For non-Emirati rare disease patients profiled by exome sequencing, the reimbursement rate was just over 8 percent, for example, while it reached 16.4 percent across all of the non-Emirati cases.
"Our study demonstrates that clinical genomic investigations should become the standard of care for patients with rare diseases in this patient population," the authors proposed. "However, significant local investments are needed to establish multidisciplinary specialized centers where genomic investigations and subsequent management and intervention plans are accessible for patients with rare disorders."