For each of the paediatric problems A–E, select the best option from the following list of causes

A. Option 4 Thyroid deficiency in children. Such children are dwarfed, mentally retarded and pot bellied. Early treatment is urgent to prevent permanent mental retardation.

B. Option 2 Adrenal cortical overactivity in children. The adrenal cortex can manufacture the sex hormones needed to initiate and maintain the secondary sexual characteristics of puberty. Disordered hypothalamic or pituitary function can also cause precocious puberty.

C. Option 1 Non-dysjunction of chromosome 21. The non-disjunction of chromosome 21 during meiosis usually occurs in the ovary and increases in frequency with the age of the mother. Both of the chromosomes go to one of the daughter cells during meiosis.

D. Option 5 An XO chromosomal pattern. In this condition (Turner’s syndrome), the zygote does not receive a sex chromosome from one of the parents. The gonads are rudimentary or absent and the child develops female external genitalia. There is small stature and sexual maturation does not occur at puberty.

E. Option 3 Pituitary deficiency. There are several causes of dwarfism but one of the causes is a hypothalamic or pituitary disorder that diminishes the secretion of growth hormone.