Corticotroph adenoma of the pituitary in a patient with X-linked adrenal hypoplasia congenita due to a novel mutation of the DAX-1 gene.

OBJECTIVE: Mutations in the DAX-1 gene result in X-linked congenital adrenal hypoplasia. The classic clinical presentation is primary adrenal insufficiency in early life and hypogonadotropic hypogonadism at the time of expected puberty, but recent data have expanded the phenotypic spectrum of DAX-1 mutations. We report the occurrence of an ACTH-secreting adenoma in a patient with X-linked congenital adrenal hypoplasia. DESIGN AND METHODS: Detailed clinical, radiological and pathological investigation of the pituitary adenoma. Genomic analysis of the DAX-1 gene in the patient and his mother. RESULTS: In this patient, primary adrenal failure had been diagnosed at 3 years of age and, despite replacement therapy, at 30 years of age progressive pigmentation developed and impairment of the visual field followed. ACTH was 24 980 pg/ml and nuclear magnetic resonance disclosed a huge pituitary adenoma. Three transsphenoidal operations and radiotherapy were necessary to remove the tumor mass and control ACTH secretion. Histologically, the adenoma was composed of chromophobic and basophilic neoplastic cells with positive immunostaining for ACTH. Moreover, a novel mutation was found both in the patient and his mother: a 4 bp insertion (AGCG) at nucleotide 259, in exon 1 resulting in a frame shift and premature termination. CONCLUSIONS: This case suggests that in adrenal hypoplasia congenita the development of a pituitary adenoma should be considered when a sudden rise of ACTH occurs despite adequate steroid substitution.

XY female with a dysgerminoma and no mutation in the coding sequence of the SRY gene.

We report a 46,XY 11-year-old girl with pure gonadal dysgenesis who developed a dysgerminoma. The testis-determining gene SRY, a candidate for sex reversal, whose alterations seem to correlate with dysgerminoma, was analyzed and found to be normal; its coding sequence was negative for deletions and mutations. DMRT-1 gene mapping on 9p and DAX-1 on Xp21 were also normal. These results suggest the involvement of other genes in sex reversal and call into question the putative relationship between SRY alterations and dysgerminoma.

Heterozygous submicroscopic inversions involving olfactory receptor-gene clusters mediate the recurrent t(4;8)(p16;p23) translocation.

The t(4;8)(p16;p23) translocation, in either the balanced form or the unbalanced form, has been reported several times. Taking into consideration the fact that this translocation may be undetected in routine cytogenetics, we find that it may be the most frequent translocation after t(11q;22q), which is the most common reciprocal translocation in humans. Case subjects with der(4) have the Wolf-Hirschhorn syndrome, whereas case subjects with der(8) show a milder spectrum of dysmorphic features. Two pairs of the many olfactory receptor (OR)-gene clusters are located close to each other, on both 4p16 and 8p23. Previously, we demonstrated that an inversion polymorphism of the OR region at 8p23 plays a crucial role in the generation of chromosomal imbalances through unusual meiotic exchanges. These findings prompted us to investigate whether OR-related inversion polymorphisms at 4p16 and 8p23 might also be involved in the origin of the t(4;8)(p16;p23) translocation. In seven case subjects (five of whom both represented de novo cases and were of maternal origin), including individuals with unbalanced and balanced translocations, we demonstrated that the breakpoints fell within the 4p and 8p OR-gene clusters. FISH experiments with appropriate bacterial-artificial-chromosome probes detected heterozygous submicroscopic inversions of both 4p and 8p regions in all the five mothers of the de novo case subjects. Heterozygous inversions on 4p16 and 8p23 were detected in 12.5% and 26% of control subjects, respectively, whereas 2.5% of them were scored as doubly heterozygous. These novel data emphasize the importance of segmental duplications and large-scale genomic polymorphisms in the evolution and pathology of the human genome.