Aim: To study a 46, XY newborn patient with a phenotype suggestive of an androgen insensitivity syndrome to confirm an anomaly in the AR gene. Methods: Genomic DNA from leukocytes was isolated in order to analyze SRY gene by PCR and sequencing of the eight exons of AR gene. Isolation of human Leydig cell mesenchymal precursors from the testis was performed in order to study testosterone production and response to hCG stimulation in culture. Results: Surgical exploration disclosed two testes, no Wolffian structures and important Mllerian derivatives. The SRY gene was present in peripheral blood leukocytes. Sequencing of the AR gene evidenced a previously unreported G to T transversion in exon 1 that changed the normal glutamine 153 codon to a stop codon. Interstitial cell cultures produced sizable amounts of testosterone and were responsive to hCG stimulation. Conclusion: This E153X nonsense point mutation has not been described previously in cases of AIS, and could lead to the synthesis of a short truncated (153 vs 919 residues) non functional AR probably responsible for the phenotype of complete androgen insensitivity syndrome (CAIS).

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