Gene Testing in the Kingdom of Saudi Arabia
Single Gene Disorders
These genetic conditions are caused by mutations in a single gene. They follow Mendelian inheritance patterns and could be autosomal dominant, autosomal recessive, or X-linked. Examples include cystic fibrosis (autosomal recessive; affects lungs and digestive system), sickle cell anemia (autosomal recessive; causes abnormal red blood cells), Huntington’s Disease (autosomal dominant; leads to progressive brain disorder), and hemophilia (X-linked recessive; impairs blood clotting).
Carrier Detection
Carrier detection identifies individuals who carry one copy of a mutated gene for a recessive genetic disorder. Carriers usually show no symptoms but can pass the gene to offspring. This test is important for autosomal recessive and X-linked conditions. The DNA test is performed to assess genetic risk in couples. Examples include cystic fibrosis, thalassemia, and Tay-Sachs disease.
Prenatal Genetic Testing
Prenatal genetic testing involves testing a fetus for genetic abnormalities before birth. It helps detect inherited disorders or chromosomal anomalies early in pregnancy. The test informs parental decisions, and guides early medical care or intervention. Diagnostic tests include amniocentesis, chorionic villus sampling, and the new non-invasive blood testing that detects cell-free fetal DNA (cfDNA) in the maternal circulation.
APOE Genotyping
APOE (Apolipoprotein E) genotyping identifies variants of the APOE gene, which influence lipid metabolism and risk for certain diseases, especially Alzheimer’s. The allele ε2 may reduce Alzheimer's risk, while the most common allele ε3 has only a neutral risk. The allele ε4 is associated with higher risk of late-onset Alzheimer's disease. The test is used to assess genetic risk for Alzheimer’s, guide personalized prevention strategies, and evaluate cardiovascular risk. The DNA test is done via a blood sample or a saliva sample.
