A disruptive mutation in exon 3 of the GNAS gene with albright hereditary osteodystrophy, normocalcemic pseudohypoparathyroidism, and selective long transcript variant Gsalpha-L deficiency.

Objective: The GNAS gene encodes the alpha-subunit of stimulatory G proteins, which play a crucial role in intracellular signal transduction of peptide and neurotransmitter receptors. In addition to transcript variants that differ in their first exon due to different promoters, there are two long (Gsalpha-L) and two short (Gsalpha-S) splice variants, created by alternative splicing. Heterozygous inactivating maternally inherited mutations of GNAS lead to a phenotype in which Albright hereditary osteodystrophy is associated with pseudohypoparathyroidism type Ia.

The A645D mutation in the hinge region of the human androgen receptor (AR) gene modulates AR activity, depending on the context of the polymorphic glutamine and glycine repeats.

Background: Sufficient androgen receptor (AR) activity is crucial for normal male sexual differentiation. Here we report on two unrelated 46, XY patients suffering from undervirilization and genital malformations. Both patients had a short polyglycine (polyG) repeat of 10 residues and a relatively long polyglutamine (polyQ) repeat of 28 and 30 residues within the transactivation domain of the AR.

Homozygous disruption of P450 side-chain cleavage (CYP11A1) is associated with prematurity, complete 46,XY sex reversal, and severe adrenal failure.

Disruption of the P450 side-chain cleavage cytochrome (P450scc) enzyme due to deleterious mutations of the CYP11A1 gene is thought to be incompatible with fetal survival because of impaired progesterone production by the fetoplacental unit. We present a 46,XY patient with a homozygous disruption of CYP11A1. The child was born prematurely with complete sex reversal and severe adrenal insufficiency.

A novel homozygous disruptive mutation in the SRD5A2-gene in a partially virilized patient with 5alpha-reductase deficiency.

Steroid 5alpha-reductase deficiency is a rare autosomal recessive disorder caused by mutations in the SRD5A2-gene, resulting in diminished dihydrotestosterone (DHT) formation and, hence, in a severe virilization deficit of the external genitalia in patients with 46,XY karyotype. The phenotype of affected individuals is variable and has been reported to range from completely female over genital ambiguity to normal male, depending on the type of mutation and its effect on enzyme activity. Here we report an adolescent 46,XY patient with predominantly female appearance, who had been gonadectomized in early infancy.