Glucocorticoid Deficiency 3

Description

Familial isolated glucocorticoid deficiency is an adrenocortical failure characterized by very low levels of plasma cortisol despite high levels of plasma adrenocorticotropin (ACTH). Moreover, the adrenal response to ACTH is severely impaired. There is no mineralocorticoid deficiency and the renin-angiotensin system is not affected (summary by Genin et al., 2002).

For a general phenotypic description and a discussion of genetic heterogeneity of familial glucocorticoid deficiency, see GCCD1 (202200).

Mapping

Genin et al. (2002) found evidence of linkage to chromosome 8q in 3 of 14 families with glucocorticoid deficiency and no mutations in the MC2R gene. These 3 families were consanguineous, and the locus, which they called FGD2, could be mapped by homozygosity between markers D8S285 and D8S1718 in an 8.8-cM region spanning 8q11.2-q13.2.

Nomenclature

Forms of isolated glucocorticoid deficiency not caused by mutation in the MC2R gene were termed type 2 by Genin et al. (2002). Because of the demonstration of mutations in the MRAP gene causing glucocorticoid deficiency (see 609196), that form is here designated type 2, whereas the form mapping to 8q11.2-q13.2 is designated type 3.