Adrenocortical hyperfunction.

Aldosterone's main actions are to regulate intravascular volume and serum electrolytes by controlling sodium absorbtion and potassium excretion in the distal nephron. Inherited defects in aldosterone biosynthesis thus cause hypovolemia, hyponatremia and hyperkalemia. Defective aldosterone biosynthesis may be caused by congenital adrenal hyperplasia due to 21-hydroxylase (CYP21) deficiency, in which case cortisol biosynthesis is also affected, or as an isolated defect termed aldosterone synthase (corticosterone methyloxidase, CYP11B2) deficiency. Many mutations have been documented in each of these genes; in general enzymatic activity must be reduced to <1% of normal for aldosterone biosynthesis to be impaired. An additional form of familial hyperreninemic hypoaldosteronism has been described that is not due to mutations in CYP11B2, but its etiology remains to be elucidated.

Adrenal Hyperplasia, Congenital↗

PubMed2004

Parents of children with autosomal recessive diseases are not always carriers of the respective mutant alleles.

Classically, each parent of a child with an autosomal recessive disease has been considered to carry at least one copy of the abnormal allele. However, with the increasing ability to characterise the molecular basis of genetic diseases, several exceptions have been reported. The most frequent situation is that only one parent is a carrier of the mutation that is present in the patient in two copies either because of uniparental disomy or because of a de-novo mutation on the gene transmitted by the non-carrier parent. In order to give accurate genetic counselling, in particular when prenatal diagnosis is envisaged, molecular analysis of each of the parents of a child affected with an autosomal recessive disease must be routinely performed.

Adrenal Hyperplasia, Congenital↗