4 causes of mental retardation in children

mental retardation

Mental retardation also called intellectual disability is a condition in which a person has below average intelligence which limits their ability to function normally. People with intellectual disabilities can and usually learn new skills, but they learn them more slowly. Mental retardation which is more common in boys than girls, begins at birth or in childhood.

 There are four levels of mental retardation: mild, moderate, severe, and profound. These levels are determined by performance on standardized IQ tests and by the potential to learn adaptive skills such as communication and social interaction.

Symptoms of mental retardation

Symptoms vary based on a child’s level of disability and may include:

  • failure to meet intellectual standards
  • sitting, crawling, or walking later than other children
  • problems learning to talk or trouble speaking clearly
  • memory problems
  • inability to understand the consequences of actions
  • inability to think logically
  • childish behavior inconsistent with the child’s age
  • lack of curiosity
  • learning difficulties
  • inability to lead a normal life due to challenges communicating, taking care of themselves, or interacting with others

Causes of mental retardation

1. Problems during pregnancy

mental retardation

If you are pregnant and drink too much alcohol, your risk of having a mentally retarded child through a condition known as fetal alcohol syndrome (FAS) increases.

Drug abuse of substances like cocaine or amphetamines and infections in pregnant women such as German measles (rubella) or toxoplasmosis may harm the mental development of the unborn child leading to babies being born with mental retardation.

Maternal malnutrition and exposure to radiation during pregnancy can also cause mental retardation.

2. Complications during or after birth

mental retardation

This could be brought about by trauma during birth, such as oxygen deprivation or premature delivery.

Mental retardation can also be caused by problems after birth such as lead or mercury poisoning, severe malnutrition, accidents that cause severe head injuries, an interruption in the supply of oxygen to the brain (for example, near-drowning experiences), or diseases such as encephalitis, meningitis, and untreated hypothyroidism in infants. Some of these conditions are more likely to occur in children raised in circumstances of severe poverty, neglect, or abuse.

3. Genetics

mental retardation

If one or both parents have mental retardation, there is a much greater chance that their children will also have this condition. Other inherited disorders include as phenylketonuria (PKU) or Tay-Sachs disease.

PKU is a birth defect that causes an amino acid called phenylalanine to build up in the body. If untreated, it can lead to intellectual disability, seizures, behavioral problems and mental disorders

Tay-Sachs disease is a rare inherited disorder that progressively destroys nerve cells (neurons) in the brain and spinal cord.

4. Chromosome abnormalities

mental retardation

Sometimes mental retardation is caused by an abnormality in the chromosomes rather than the individual genes. Down syndrome, one of the most common causes of mental retardation, is caused by an extra chromosome in the cells.

Another fairly common chromosomal defect is fragile X also termed Martin-Bell syndrome or marker X syndrome. Fragile X syndrome causes mild to severe intellectual disability and is more common in boys than girls. Children with Fragile X often have learning, behavioural and developmental problems. They can find it hard to understand or process information.


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