Scientific background:

Summary: In the distal nephron the mineralocorticoid receptor receptor binds aldosterone and activates several transcription factors that lead to activation of the epithelial sodium channel. The disease caused by mutations is autosomal dominant pseudohypoaldosteronism 1.

Gene: The gene stretches over 365kb on chromosome 4 (4q31.1). It consists of 9 exons, 8 of them transcribed. Exon 1 exists in two different splice variants; both regulated by an other promoter. Because translation starts in exon 2, however, translation products are the same.

Molecular anatomy: In colon, kidney, and salivary glands, this receptor controls the sodium channel ENaC. By this pathway aldosterone controls sodium uptake into the cell and consequently into the body and ensures sodium and water balance as well as blood pressure regulation. In the kidney, aldosterone sensitive epithelial cells are located in the distal nephron.

Methodology:

	clinical test	Method		Genomic sequencing of the entire coding region
		Turn-around time		25 working days
		Effort		medium
		Specimen		DNA
		Quality assessment		Internal quality control only
	All known and new missense, nonsense and splice mutations can be detected.
	clinical test	Method		Carrier testing
		Turn-around time		5 working days
		Effort		little
		Specimen		DNA
		Quality assessment		Internal quality control only
	The test is only specific about the mutation already known in this kindred.

Literature: 

Rogerson FM et al. (2003) Dissecting mineralocorticoid receptor structure and function.
Fuller PJ et al. (2005) Mechanisms of mineralocorticoid action.