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Women with congenital adrenal hyperplasia due to 21-hydroxylase deficiency often have a polycystic ovary-like syndrome, consisting of hyperandrogynism, infertility, menstrual irregularities, and elevated LH levels. This is generally considered secondary to poor control of the congenital adrenal hyperplasia. However, our experience led us to suspect that ovarian hyperandrogenism occurs even when congenital adrenal hyperplasia is well controlled on glucocorticoid therapy. Therefore, we tested the hypothesis that congenital adrenal virilizing disorders result in ovarian hyperandrogenism. We studied eight women with congenital adrenal virilizing disorders, seven with well controlled classic 21-hydroxylase deficiency and one with congenital virilizing adrenal carcinoma removed at 1.7 yr of age. We also studied six women with late-onset 21-hydroxylase deficiency, without signs of congenital virilization. An ovarian source of androgens was assessed after suppressing adrenal function with dexamethasone and then testing pituitary-ovarian function by a GnRH agonist (nafarelin) test. Five women with congenital adrenal virilizing disorders (four with classic 21-hydroxylase deficiency and one with congenital virilizing adrenal carcinoma) and one women with late-onset 21-hydroxylase deficiency had ovarian hyperandrogenism as determined by subnormal suppression of free testosterone after dexamethasone and/or by increased 17-hydroxyprogesterone response to nafarelin while on dexamethasone. All women with congenital adrenal virilization and ovarian hyperandrogenism had elevated LH levels after dexamethasone or elevated early LH response to nafarelin, which suggests that LH excess is the cause of their ovarian hyperandrogenism. This was not the case for the late-onset 21-hydroxylase-deficient woman. Our data are compatible with the hypothesis that congenital adrenal virilization programs the hypothalamic-pituitary axis for hypersecretion of LH at puberty. This is postulated to frequently cause ovarian hyperandrogenism even when adrenal androgen excess is subsequently controlled by glucocorticoid therapy.

The DAX1 protein is an orphan nuclear hormone receptor based on sequence similarity in the putative ligand-binding domain (LBD). DAX1 mutations result in X-linked adrenal hypoplasia congenita (AHC). Our objective was to identify DAX1 mutations in a series of families, to determine the types of mutations resulting in AHC and to locate single-amino-acid changes in a DAX1 structural model. The 14 new mutations identified among our 17 families with AHC brought the total number of families with AHC to 48 and the number of reported mutations to 42; 1 family showed gonadal mosaicism. These mutations included 23 frameshift, 12 nonsense, and six missense mutations and one single-codon deletion. We mapped the seven single-amino-acid changes to a homology model constructed by use of the three-dimensional crystal structures of the thyroid-hormone receptor and retinoid X receptor alpha. All single-amino-acid changes mapped to the C-terminal half of the DAX1 protein, in the conserved hydrophobic core of the putative LBD, and none affected residues expected to interact directly with a ligand. We conclude that most genetic alterations in DAX1 are frameshift or nonsense mutations and speculate that the codon deletion and missense mutations give insight into the structure and function of DAX1.

A 12-yr-old hypothyroid girl was diagnosed at birth as athyreotic because her thyroid gland could not be visualized by isotope scanning. Goiter development due to incomplete thyrotropin suppression, a thyroidal radioiodide uptake of < 1%, and a low saliva to plasma ratio of 2.5 suggested iodide (I-) transport defect. mRNA isolated from her thyroid gland and injected into Xenopus oocytes failed to increase I- transport. Sequencing of the entire Na+/I- symporter (NIS) cDNA revealed a C to G transversion of nucleotide (nt) 1146 in exon 6, resulting in a Gln 267 (CAG) to Glu (GAG) substitution. This missense mutation produces an NIS with undetectable I- transport activity when expressed in COS-7 cells. Although only this missense mutation was identified in thyroid and lymphocyte cDNA, genotyping revealed that the proposita and her unaffected brother and father were heterozygous for this mutation. However, amplification of cDNA with a primer specific for the wild-type nt 1146 yielded a sequence lacking 67 nt. Genomic DNA showed a C to G transversion of nt 1940, producing a stop codon as well as a new downstream cryptic 3' splice acceptor site in exon 13, responsible for the 67 nt deletion, frameshift, and premature stop predicting an NIS lacking 129 carboxy-terminal amino acids. This mutation was inherited from the mother and present in the unaffected sister. Thus, although the proposita is a compound heterozygote, because of the very low expression (< 2.5%) of one mutant allele, she is functionally hemizygous for an NIS without detectable bioactivity.

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