Molecular diagnosis is rarely established in 46,XX testicular (T) disorder of sex development (DSD) individuals with atypical genitalia. The Wilms' tumour factor‐1 (WT1) gene is involved in early gonadal development in both sexes. Classically, WT1 deleterious variants are associated with 46,XY disorders of sex development (DSD) because of gonadal dysgenesis. We report a novel frameshift WT1 variant identified in an SRY‐negative 46,XX testicular DSD girl born with atypical genitalia. Target massively parallel sequencing involving DSD‐related genes identified a novel heterozygous WT1 c.1453_1456del; p.Arg485Glyfs*14 variant located in the fourth zinc finger of the protein which is absent in the population databases. Segregation analysis and microsatellite analysis confirmed the de novo status of the variant that is predicted to be deleterious by in silico tools and to increase WT1 target activation in crystallographic model. This novel and predicted activating frameshift WT1 variant leading to the 46,XX testicular DSD phenotype includes the fourth zinc‐finger DNA‐binding domain defects in the genetic aetiology of 46,XX DSD.

Background Although congenital adrenal hyperplasia (CAH) is known to be associated with adrenal crises (AC), its association with patient or clinician reported sick day episodes (SDE) is less clear. Methods Data on children with classic 21-hydroxylase deficiency CAH from 34 centers in 18 countries, of which 7 were Low or Middle Income (LMIC) and 11 were High Income (HIC), were collected from the International CAH Registry and analysed to examine the clinical factors associated with SDE and AC. Results 518 children with a median of 11 children (range 1, 53) per center had 5,388 visits evaluated over a total of 2,300 patient years. The median number of AC and SDE per patient year per center was 0 (0, 3) and 0.4 (0.0, 13.3), respectively. Of the 1,544 SDE, an AC was reported in 62 (4%), with no fatalities. Infectious illness was the most frequent precipitating event, reported in 1,105 (72%) and 29 (47%) of SDE and AC, respectively. On comparing cases from LMIC and HIC, the median SDE per patient year was 0.75 (0, 13.3) vs 0.11 (0, 12.0) (p<0.001), respectively and the median AC per patient year was 0 (0, 2.2) vs 0 (0, 3.0) (p=0.43), respectively. Conclusions The real-world data that are collected within the I-CAH Registry show wide variability in the reported occurrence of adrenal insufficiency related adverse events. As these data become increasingly used as a clinical benchmark in CAH care, there is a need for further research to improve and standardise the definition of SDE.

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