Targeted massively parallel sequencing provides comprehensive genetic diagnosis for patients with disorders of sex development.

Disorders of sex development (DSD) are rare disorders in which there is discordance between chromosomal, gonadal, and phenotypic sex. Only a minority of patients clinically diagnosed with DSD obtains a molecular diagnosis, leaving a large gap in our understanding of the prevalence, management, and outcomes in affected patients. We created a novel DSD-genetic diagnostic tool, in which sex development genes are captured using RNA probes and undergo massively parallel sequencing. In the pilot group of 14 patients, we determined sex chromosome dosage, copy number variation, and gene mutations. In the patients with a known genetic diagnosis (obtained either on a clinical or research basis), this test identified the molecular cause in 100% (7/7) of patients. In patients in whom no molecular diagnosis had been made, this tool identified a genetic diagnosis in two of seven patients. Targeted sequencing of genes representing a specific spectrum of disorders can result in a higher rate of genetic diagnoses than current diagnostic approaches. Our DSD diagnostic tool provides for first time, in a single blood test, a comprehensive genetic diagnosis in patients presenting with a wide range of urogenital anomalies.

Xenoxins, a family of peptides from dorsal gland secretion of Xenopus laevis related to snake venom cytotoxins and neurotoxins.

Three new, highly similar peptides from the skin secretion of Xenopus laevis have been purified and analyzed by mass spectrometry and Edman degradation. The 66-amino-acid peptides, termed xenoxin-1, -2, and -3, contain 8 cysteines and show similarity to snake venom cytotoxins and short neurotoxins. Assignment of two out of four disulfide bonds suggests a tertiary structure similar to that of cytotoxins and short neurotoxins. A cDNA encoding pre-xenoxin-1 was isolated from a X. laevis skin cDNA library. The nucleotide sequence predicts the synthesis of a precursor with a signal peptide followed by the sequence of the mature peptide. Xenoxin-1 and -2 lack alpha-neurotoxic activity, have apparently no antibacterial activity, are low in general toxicity as tested in mice, and have no effect on blood coagulation as measured in a Factor VIII procoagulant activity test. Potential functions of xenoxins as well as evolutionary aspects are discussed.