Nephrogenic syndrome of inappropriate antidiuresis - An ethnically, genetically and phenotypically diverse disorder: First report in a Chinese adult and review of published cases.

BACKGROUND: Nephrogenic syndrome of inappropriate antidiuresis (NSIAD) is a rare inherited disorder characterised by hyponatraemia. To date, most reported cases are Caucasians with gain-of-function variants in AVPR2, an X-linked gene which encodes the vasopressin V2 receptor (V2R). Recently, germline gain-of-function variants in the stimulatory G protein α-subunit (Gsα) were reported to cause dominantly inherited NSIAD. CASE REPORT: We report the first Chinese adult diagnosed with NSIAD. He was found to be hemizygous for R137C-V2R, the most prevalent pathogenic variant among Caucasians. After the genetic diagnosis and counselling on the importance of fluid restriction, he had no recurrence of hyponatraemia to date. LITERATURE REVIEW: Case reports of NSIAD published in the English literature in PubMed were reviewed to summarise the genetic and phenotypic heterogeneity of this disorder. CONCLUSION: NSIAD is ethnically, genetically and phenotypically diverse. The diagnosis should especially be considered in young patients with otherwise unexplained hyponatraemia. Target analysis of R137C-V2R should make the diagnosis in most cases. Genetic testing could confirm the diagnosis, motivate adherence to treatment, offer the possibility of genotype-guided therapy, and allow cascade screening to prevent hyponatraemia.

Validation of the Drug Abuse Screening Test (DAST-10): A study on illicit drug use among Chinese pregnant women.

We assessed the Chinese version of the Drug Abuse Screening Test (DAST-10) for identifying illicit drug use during pregnancy among Chinese population. Chinese pregnant women attending their first antenatal visit or their first unbooked visit to the maternity ward were recruited during a 4-month study period in 2011. The participants completed self-administered questionnaires on demographic information, a single question on illicit drug use during pregnancy and the DAST-10. Urine samples screened positive by the urine Point-of-Care Test were confirmed by gas chromatography-mass spectrometry. DAST-10 performance was compared with three different gold standards: urinalysis, self-reported drug use, and evidence of drug use by urinalysis or self-report. 1214 Chinese pregnant women participated in the study and 1085 complete DAST-10 forms were collected. Women who had used illicit drugs had significantly different DAST-10 scores than those who had not. The sensitivity of DAST-10 for identify illicit drug use in pregnant women ranged from 79.2% to 33.3% and specificity ranged from 67.7% to 99.7% using cut-off scores from ≥ 1 to ≥ 3. The ~ 80% sensitivity of DAST-10 using a cut-off score of ≥ 1 should be sufficient for screening of illicit drug use in Chinese pregnant women, but validation tests for drug use are needed.