Recently it has been increasingly obvious that androgen receptor mutations not only result in the complete androgen insensitivity syndrome, but can cause a wide spectrum of milder insensitivity syndromes including ambiguous genitalia in newborn infants, and 'idiopathic' male infertility in otherwise normal males.
A mutation in the DNA-binding domain of the androgen receptor gene causes complete testicular feminization in a patient with receptor-positive androgen resistance.
Shortage of glutamine (CAG) homopolymeric repeats suppresses the expression of the androgen receptor in familial cases with complete androgen insensitivity syndrome.
A single amino acid substitution (Met786----Val) in the steroid-binding domain of human androgen receptor leads to complete androgen insensitivity syndrome.
The androgen receptor gene has been isolated, cloned, and studied extensively in patients with complete androgen insensitivity syndrome, but no comparative data are available on infertile males.
These experiments revealed that the functional difference between a mutant AR that causes a partial and one that causes a complete androgen insensitivity may be very small.
Although CAIS is the best known phenotype, recent studies from our laboratory and elsewhere show that malfunction of the AR is associated with many androgen-regulated diseases or conditions that cross traditional clinical disciplines ranging from paediatrics (ambiguous genitalia), gynaecology (primary amenorrhoea), urology (prostate cancer), neurology (spinal bulbar muscular atrophy), reproductive medicine (male infertility), orthopedics (rheumatoid arthritis), oncology (breast cancer) and dermatology (hirsutism, baldness and acne).
This review summarizes the most recent information on two pathologies linked to mutations of the androgen receptor, namely, the complete androgen insensitivity syndrome (CAIS) and the spinal and bulbar muscular atrophy (SBMA or Kennedy's disease).
Finally, the GSF of two exceptional patients with complete androgen insensitivity syndrome due to negligible androgen receptor-binding activity express this protein normally, as determined on two-dimensional gels by Western blot analysis with the antiserum and by photolytic covalent labeling with androgen analogues.
This tentative theory is partially supported by lower 2D:4D in girls with congenital adrenal hyperplasia (CAH), higher 2D:4D in individuals with complete androgen insensitivity syndrome (CAIS) and a relationship between 2D:4D and polymorphisms in the androgen receptor.
A naturally occurring mutation in the human androgen receptor of a subject with complete androgen insensitivity confers binding and transactivation by estradiol.
It was concluded that the novel c.C2754 > T transition rendered the androgen receptor incapable of both ligand binding and activating the transcription, and was the cause of CAIS in the patient.
When assayed using this method, the AR function of patients with Reifenstein syndrome was intermediate between that of normal control subjects and that of patients with complete testicular feminization.
Complete or gross deletions of the androgen receptor gene have not been frequently found in persons with the complete androgen insensitivity syndrome, whereas point mutations at several different sites in exons 2-8 encoding the DNA- and androgen-binding domain have been reported in both partial and complete forms of androgen insensitivity, with a relatively high number of mutations in two clusters in exons 5 and 7.
Two substitutions at an identical location in the ligand-binding domain (LBD) of the human androgen receptor (AR), R855C and R855H, are associated with complete androgen insensitivity syndrome (AIS) and partial AIS, respectively.
We have defined the molecular defect in the androgen receptor in four unrelated subjects in this category (termed receptor positive) with the phenotype of compete or incomplete testicular feminization.