The diagnostic yield of CGH and WES in neurodevelopmental disorders

Background

Neurodevelopmental disorders are a group of conditions characterized by developmental delays leading to abnormal brain functions. The methods of diagnosis and treatment of these conditions are complicated, and their treatment involves a combination of various forms of therapy. In recent years, the development of high-resolution technologies has played an important role in revealing the microdeletions, microduplications, and single-nucleotide variants of the chromosomes and how they are linked to the development of neurodevelopmental disorders. The wide implementation and application of molecular methodologies have started to shed light on the functional importance of using the appropriate methods in detecting these genetic variations that are categorized as either pathogenic or benign. The study aimed to compare the diagnostic yield of comparative hybridization (CGH) and whole exome sequencing (WES) in neurodevelopmental disorders among children attending the King Abdullah Specialist Children Hospital, Riyadh, Saudi Arabia.

Methods

A retrospective study was conducted between 2015 and 2018 on 105 patients diagnosed with neurodevelopmental disorders through array-based CGH (Array-CGH) and WES.

Results

In a sample of 105 patients, 16% was the hit rate of copy number variations (CNVs). WES was requested for CNV-negative patients (n = 79), of which 30% was the hit rate of pathogenic or likely pathogenic single-nucleotide variants. There was a difference in the diagnostic yield between CGH (16%) and WES (30%).

Conclusion

WES was a better approach than Array-CGH to detect various DNA mutations or variants. Our findings could guide clinicians, researchers, and testing laboratories select the most cost-effective and appropriate approach for diagnosing their patients.

International Newborn Screening: Where Are We in Saudi Arabia?

Newborn screening (NBS) programs are believed to play an important role in the decrease of infant mortality rates in many countries. This is achieved through offering early detection and treatment of many genetic as well as metabolic disorders prior to the onset of symptoms. Our paper examines NBS across seven diverse nations: Saudi Arabia, the United States, Japan, Singapore, Canada, Australia, and the United Kingdom. This paper discusses the diseases screened for by each country, latest additions, as well as future recommendations, when applicable. Employing a comparative approach, we conducted a comprehensive review of the most recent published literature on NBS programs in each country and subsequently examined their latest implemented NBS guidelines as outlined on their respective official government health sector websites. We then reviewed the economic feasibility of each of these programs and factors that affect implementation and overall benefit. While all six countries employ well-developed programs, variations are observed. Those variations are mainly attributed to disparities in access, resource scarcity, financial availability, as well as ethical and cultural considerations. From a local perspective, we recommend conducting further population-based studies to assess the epidemiological data in relation to the disease burden on the country's economy. Moreover, we recommend updating national and international guidelines to contain a more comprehensive approach on policies, operation, and sustainability to deliver a service through the lens of value-based healthcare.

Bipolar Disorders in Saudi Arabia: What Do We Know So Far?

Bipolar disorders (BP) are prevalent neuropsychiatric illnesses affecting 1%-5% of the global population and about 3% of the Saudi population. They are associated with significant comorbidities and negative consequences. Despite being common mental health conditions in Saudi Arabia, stigma persists, with weak character, supernatural beliefs, and weak faith considered as causes. In addition, Saudi patients with BP have been reported to seek help from non-psychiatric healthcare professionals and faith healers. More data are required on BP from Saudi Arabia, including the genetic aspects and their treatment approaches. This narrative review paper explores the epidemiology and clinical manifestations, etiology and biological mechanisms, public knowledge and awareness of the illnesses, and treatment of BP in Saudi Arabia.