What are the indications for prenatal diagnosis in the androgen insensitivity syndrome? Facing clinical heterogeneity of phenotypes for the same genotype

The approach to a neonate with a possible prenatal diagnosis of androgen insensitivity syndrome

The diagnosis of androgen insensitivity syndrome (AIS) can now be made prenatally. We present a patient for whom the diagnosis of AIS was highly suspected prenatally, but the parents preferred to deny it. The clinical findings and the diagnostic evaluation after delivery are presented. A brief discussion of the syndrome, as well as the implications of possible prenatal diagnosis and how to approach it, are provided. Full multidisciplinary diagnostic work-up immediately after delivery, as well as awareness of possible prenatal diagnosis, is the responsibility of the primary care provider for the newborn with suspected AIS.

Persistence of Müllerian remnants in complete androgen insensitivity syndrome

One of the unusual findings in androgen insensitivity syndrome (AIS) is the persistence of Mullerian derivatives. Several hypotheses have been advanced to explain such persistence: the coincidental occurrence of mutations affecting the androgen receptor (AR) and the synthesis and/or action of anti-Müllerian hormone (AMH); the loss of AMH paracrine action due to early testicular descent; the exposure to drugs such as diethylstilbestrol. We describe a patient with complete AIS for whom surgical and laboratory findings rule out all these hypotheses. She has a missense mutation on the AR gene but no mutations were detected on the genes coding for AMH and AMH receptor. The gonads were found very close to the Mullerian structures (enough to exert a paracrine action), gonadal tissue stained positively for AMH, and yet Mullerian derivatives were present and well developed. These findings indicate the possibility of interactions between the androgen receptor and AMH action.

Molecular analysis of the androgen-receptor gene in a family with receptor-positive partial androgen insensitivity: an unusual type of intronic mutation

In the coding part and the intron-exon boundaries of the androgen-receptor gene of a patient with partial androgen insensitivity, no mutation was found. The androgen receptor of this patient displayed normal ligand-binding parameters and migrated as a 110-112-kD doublet on SDS-PAGE in the absence of hormone. However, after culturing of the patient's genital skin fibroblasts in the presence of hormone, the slower-migrating 114-kD protein, which reflects hormone-dependent phosphorylation, was hardly detectable. Furthermore, receptor protein was undetectable in the nuclear fraction of the fibroblasts, after treatment with hormone, which is indicative of defective DNA binding. By sequencing part of intron 2, a T-->A mutation was found 11 bp upstream of exon 3. In our screening of 102 chromosomes from unrelated individuals, this base-pair substitution was not found, indicating that it was not a polymorphism. mRNA analysis revealed that splicing involved a cryptic splice site, located 71/70 bp upstream of exon 3, resulting in generation of mRNA with an insert of 69 nucleotides. In addition, a small amount of a transcript with a deleted exon 3 and a very low level of wild-type transcript were detected. Translation of the extended transcript resulted in an androgen-receptor protein with 23 amino acid residues inserted between the two zinc clusters, displaying defective DNA binding and defective transcription activation.