Genetic landscape of recessive diseases in the Vietnamese population from large‐scale clinical exome sequencing

AbstractPurposeAccurate profiling of population-specific recessive diseases is essential for the design of cost-effective carrier screening programs. However, minority populations and ethnic groups, including Vietnamese, are still under-represented in existing genetic studies. Here we reported the first comprehensive study of recessive diseases in the Vietnamese population.MethodsClinical exome sequencing (CES) data of 4,503 disease-associated genes obtained from a cohort of 985 Vietnamese individuals was analyzed to identify pathogenic variants, associated diseases and their carrier frequencies in the population.ResultsEighty-five recessive diseases were identified in the Vietnamese population, among which seventeen diseases had carrier frequencies of at least 1% (1 in 100 individuals). Three diseases were especially prevalent in the Vietnamese population with carrier frequencies of 2-12 times higher than in other East Asia or the world populations, including Beta-thalassemia (1 in 25), citrin deficiency (1 in 33) and phenylketonuria (1 in 40). Seven novel pathogenic and three likely pathogenic variants associated with nine recessive diseases were also discovered.ConclusionsThe comprehensive profile of recessive diseases identified in this study shall enable the design of cost-effective carrier screening programs specific to the Vietnamese population. The newly discovered pathogenic variants may also exist in other populations at extremely low frequencies, thus representing a valuable resource for future research. Our study has demonstrated the advantage of population-specific genetic studies to advance the knowledge and practice of medical genetics.

Download Full-text

An audit and insights from clinical exome sequencing in psychiatry: genotype-phenotype correlation

10.31219/osf.io/5fu6t ◽

2020 ◽

Author(s):

Jayant Mahadevan ◽

Reeteka Sud ◽

Ravi Kumar Nadella ◽

Vani P ◽

Anand G Subramaniam ◽

...

Keyword(s):

Exome Sequencing ◽

Psychiatric Symptoms ◽

Pathogenic Variant ◽

Clinical Exome Sequencing ◽

Mapt Gene ◽

Nf1 Gene ◽

Novel Variant ◽

History Of ◽

Atypical Presentations ◽

Minor Physical Anomalies

BACKGROUND:Psychiatric syndromes have polymorphic symptomatology, and are known to be heritable. Psychiatric symptoms (and even syndromes) often occur as part of the clinical presentation in rare Mendelian syndromes. Clinical exome sequencing reports may help with refining diagnosis and influence treatment decisions, in addition to providing a window into the biology of brain and behaviour. We describe a clinical audit of 12 individuals who sought treatment at our hospital, and for whom targeted sequencing was ordered. Three cases are discussed in detail to demonstrate correlations between genotype and phenotype in the clinic.METHODS:Targeted Next-Generation Sequencing (NGS) was done using Clinical Exome Panel (TruSight One, Illumina) covering coding exons and flanking intronic sequences of 4811 genes associated with known inherited diseases. Variants detected were classified according to the American College for Medical Genetics (ACMG) recommendation for standards of interpretation and reporting of sequence variations.RESULTS:Ten out of twelve cases had at least one pathogenic variant. In one of these cases, we detected a known pathogenic variant in MAPT gene in a suspected FTD case, which helped us to confirm the diagnosis. In another case, we detected a novel variant predicted to be deleterious in NF1 gene. Identification of this mutation suggested a change in treatment for the patient, that was of benefit. The same patient also harboured a novel variant in the TRIO gene. This gene may be involved in biological processes that underlie the patient’s psychiatric illness.CONCLUSIONS:The cases discussed here exemplify different scenarios under which targeted exome sequencing can find meaningful application in the clinic: confirming diagnosis (MAPT variant), or modifying treatment (NF1). We suggest that clinical exome sequencing can be a helpful addition to a clinician’s toolkit when there are expediting factors to consider— such as early-onset, strong family history of mental illness, complex/atypical presentations and minor physical anomalies or neurocutaneous markers.

Download Full-text