Causes of mental retardation

Mental retardation, defined as insufficient cognitive and adaptive development, is one of the most common human diseases with a prevalence of about 3%. Mental retardation may be isolated (not associated with other clinical manifestations) or combined with other clinical signs (syndromic mental retardation).

Approximately 3% of people have an IQ below 70, presenting disabilities in learning and adaptation processes that impact the affected individual, the family, and last but not least on the society to which he belongs.

The causes of mental retardation are extremely diverse, ranging from genetic (innate) causes to environmental factors.

Genetic factors often cause mental retardation caused by abnormal genes inherited from one parent. The most prevalent hereditary factors for mental retardation are: Down syndrome, fragile X syndrome, phenylketonuria

Factors that act during pregnancy maternal iodine deficiency, alcohol consumption, drugs, cytomegalovirus infections, rubella, etc., hypertension, low birth weight, prematurity.

Factors that act during fetal birth hypoxia (the fetus does not receive enough oxygen).

Factors that act after birth meningitis, severe malnutrition, iodine deficiency.

Genetic factors that cause mental retardation

Chromosomal abnormalities (both in number and structure) are responsible for 25 to 28% of all mental retardation cases. The most common numerical chromosomal abnormalities are caused by the presence of an extra chromosome (trisomy) or the absence of a chromosome (monosomy) from the normal set of 46 chromosomes specific to the human species. Numerical chromosomal abnormalities are easily detected by performing the karyotype.

The most common chromosomal condition is Down (trisomy 21) syndrome. Cause of mental retardation. Structural chromosomal abnormalities that accompany the loss or gain of genetic material are almost always associated with mental retardation.

Many genetic disorders are caused by defects in a single gene that are accompanied by mental retardation born of metabolic defects (metabolic diseases, the most common being phenylketonuria), fragile X syndrome, etc.

It is already well known that mental retardation can have family transmission. Numerous studies have shown that the risk of mental retardation increases in families where there is already an affected person. The Academy of Pediatrics emphasizes the importance of early identification and early evaluation of children with mental retardation. Parents who have an intellectually retarded kid are often interested in whether there is a risk that the succeeding child will have the same problem. If the underlying cause of mental retardation in the affected person has been identified, the recurrence risk may be estimated. If besides, the genetic defect has been identified, a prenatal diagnosis can be made.

In many cases, however, the genetic defect cannot be specified. In the case of isolated mental retardation and without other people affected in the family, the risk of recurrence for a new pregnancy is 8%, being higher than in the general population (2%). The diagnostic possibilities for mental retardation with genetic determinism have developed greatly in recent years; however, a clear diagnosis can be made in only 50% of cases. You may also contact medication therapy management for further approach.

CAUSE

Depending on the severity of intellectual disability, certain factors and certain diseases are more common causes. IQ only slightly / moderate below average (> 50) is more frequently influenced by family factors and cognitive stimulation. In the case of severe delays in acquisitions (IQ <50) are more common genetic causes, complications at birth, severe deprivation of parental care in the first years of life (children in institutions). However, this is not a rule, so the child's appearance, the associated physical and mental problems that may suggest the need for additional tests are always evaluated.

Of the genetic conditions, the most commonly associated with below-average IQ include:

• Down syndrome and other chromosomal disorders (Klinefelter, Tuner, etc.)

• Fragile X syndrome

• Neurofibromatosis, tuberous sclerosis

• Homocystinuria, phenylketonuria, and other metabolic disorders

Environmental factors may include:

• Alcohol or drug use during pregnancy

• Medical complications during pregnancy or at birth

• Insufficient cognitive stimulation in the family

• Symptoms and diagnosis

Delays in age-appropriate psychomotor acquisitions are diagnosed based on two major criteria:

• Intellectual or developmental coefficient below the level of chronological age

• Impairment of functioning in the main areas of life: communication, social, family, academic, self-care

Depending on IQ, intellectual disability is classified into:

• Preliminary intellect : IQ = 80-70

• Mental retardation easy : QI = 69-50

• Medium mental retardation : IQ = 49-35

• Severe mental retardation : IQ = 34-20

• Deep mental retardation : IQ <20

To establish an IQ or mental age, standardized tests for age and population are used, applied by a psychologist.

The psychiatric consultation also informs about possible causes of developmental delay, the most affected areas, the child's strengths, other psychiatric or pediatric difficulties. Other specialist consultations may be requested, depending on the problems discovered. Mental retardation is often associated with other problems, which may include:

• Behavioral and emotional disorders

• ADHD

• Learning disorders

• Autism Spectrum Disorders

• Epilepsy