X-linked adrenal hypoplasia congenita is a
genetic disorder that mainly affects males. It involves many
endocrine
The endocrine system is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs. In vertebrates, the hypothalamus is the neu ...
tissues in the body, especially the
adrenal glands.
Presentation
One of the main characteristics of this disorder is adrenal insufficiency, which is a reduction in adrenal gland function resulting from incomplete development of the gland's outer layer (the adrenal cortex). Adrenal insufficiency typically begins in infancy or in childhood and can cause vomiting, difficulty with feeding, dehydration, extremely low blood sugar (
hypoglycemia), low sodium levels, and shock. However, adult-onset cases have also been described.
See also
Addison's disease.
Affected males may also lack male sex hormones, which leads to underdeveloped reproductive tissues, undescended testicles (
cryptorchidism), delayed puberty, and an inability to father children (
infertility
Infertility is the inability of a person, animal or plant to reproduce by natural means. It is usually not the natural state of a healthy adult, except notably among certain eusocial species (mostly haplodiploid insects). It is the normal state ...
). These characteristics are known as
hypogonadotropic hypogonadism. Females are rarely affected by this disorder, but a few cases have been reported of adrenal insufficiency or a lack of female sex hormones, resulting in underdeveloped reproductive tissues, delayed puberty, and an absence of menstruation.
Genetics
Mutations in the ''
NR0B1
DAX1 (dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1) is a nuclear receptor protein that in humans is encoded by the ''NR0B1'' gene (nuclear receptor subfamily 0, group B, member 1). The ''NR0B1'' gene ...
''
gene located on the
X chromosome (Xp21.3-p21.2) cause X-linked adrenal hypoplasia congenita. The ''NR0B1'' gene provides instructions to make a transcription factor protein called DAX1 that helps control the activity of certain genes. When the ''NR0B1'' gene is deleted or mutated, the activity of certain genes is not properly controlled. This leads to problems with the development of the adrenal glands, two structures in the
brain (the
hypothalamus and
pituitary gland), and reproductive tissues (the
ovaries or
testes). These tissues are important for the production of many hormones that control various functions in the body. When these hormones are not present in the correct amounts, the signs and symptoms of adrenal insufficiency and hypogonadotropic hypogonadism can result. This condition is inherited in an X-linked recessive pattern.
Diagnosis
Management
References
Further reading
GeneReviews/NCBI/NIH/UW entry on X-Linked Adrenal Hypoplasia CongenitaInherited Adrenal Hypoplasia: Not Just for Kids!: X-linked Adrenal Hypoplasia Congenita- MedScape
External links
''This article incorporates public domain text fro
The U.S. National Library of Medicine'
{{DEFAULTSORT:X-Linked Adrenal Hypoplasia Congenita
Transcription factor deficiencies