Aetiology and prevention of LD

Question 1

Genetic factors

Answer 1

• -Downs
• sex-chromosome disorders
• deletions and duplications
• autosomal dominant and recessive disorders
• X-linked recessive and dominant conditions
• presumed polygenetic conditions
• mitochondrial and metabolic disorders

Question 2

External prenatal factors

Answer 2

• infections such as rubella, cytomegalovirus, syphilis, toxoplasmosis, herpes simplex and HIV
• exposure to drugs, alcohol. toxins etc
• maternal illness

Question 3

Perinatal factors

Answer 3

• prematurity
• infections such as meningitis, encephalitis, neonatal septiciaemia, pneumonia etc
• problems at the time of delivery
• newborn complications -resp distress, hypoglycaemia

Question 4

Post-natal factors

Answer 4

• CNS infections, intracranial tumours
• hypoxic brain injury
• head injury
• exposure to toxic agents
• psychosical environment- deprivation

Question 5

Primary prevention of LD

Answer 5

• whole population measures
• folic acid
• immunisations
• lead intoxication
• iodine deficiency
• fetal alcohol spectrum disorder
• accidents in the home and traffic accidents

Question 6

Secondary prevention of LD

Answer 6

• early recognition, diagnosis, good medical care and rehabilitation of injuries or diseases that can avoid or reduce permanent damage which could lead to LD
• screening for PKU, hypothyroidism
• genetic counselling

Question 7

Tertiary prevention

Answer 7

• helping an individual to attain his or her full developmental potentia
• medical, psychological, social support
• family support
• environmental adjustments and aids
• education

Question 8

Subcultural mental retardation

Answer 8

• E.O Lewis (1933)
• -lower extreme variant of normal IQ distribution seen in the population
• subcultural LD is often seen in social class 5 and is associated with mild rather than profound disability
• ‘biological’ mental retardation is seen across all social classes

Question 9

Subcultural LD

Answer 9

• mild, or borderline type
• more common in lower socioeconomic groups
• family members may have borderline IQ
• dysmorphic characteristics are less likely
• syndromic features not seen
• behavioural phenotypes are rare

Question 10

Biological/pathological LD

Answer 10

• moderate, severe or profound type
• evenly distributed across social groups
• family members often have a normal IQ
• dysmorphic characters are very common
• dynfromic features are often seen
• behavioural phenotypes are frequent