Final Answer:
The two most common causes of Intellectual Disability (ID) are genetic conditions, such as Down syndrome, and environmental factors, such as prenatal exposure to alcohol or infections.
Step-by-step explanation:
Intellectual Disability (ID) can be caused by various factors, but the two most common causes are genetic conditions and environmental factors. Genetic conditions refer to abnormalities in the genes that can lead to intellectual disabilities. For example, Down syndrome is a genetic condition caused by the presence of an extra copy of chromosome 21. Individuals with Down syndrome may exhibit symptoms such as delayed development, characteristic facial features, and mild to moderate intellectual disability.
On the other hand, environmental factors, such as prenatal exposure to alcohol or infections, can also cause ID. Fetal Alcohol Syndrome (FAS) is a well-known example of an environmental factor leading to ID. Prenatal exposure to alcohol can result in a range of developmental and cognitive impairments in the affected individual. Symptoms of FAS may include facial abnormalities, growth deficiencies, and intellectual disabilities.
One peer-reviewed article on genetic causes of ID is “Genetic Causes of Intellectual Disability” by Ropers HH and Hamel BC. This article provides an in-depth analysis of various genetic causes of intellectual disability, including chromosomal abnormalities and single-gene disorders. It discusses the molecular mechanisms underlying these genetic conditions and their impact on cognitive function.
Another peer-reviewed article on environmental causes of ID is “Prenatal Alcohol Exposure and Fetal Alcohol Spectrum Disorder: A Population Based Study” by Popova S et al. This study examines the prevalence and impact of prenatal alcohol exposure on fetal development, leading to fetal alcohol spectrum disorders (FASD). It highlights the cognitive and behavioral consequences of prenatal alcohol exposure, contributing to intellectual disabilities in affected individuals.