Although a number of contributors to the aetiology of hypospadias have been identified, the majority of risk factors remain unknown.

and proximal (43). Adjusted odds ratios (OR) with 95% confidence intervals (CI) were estimated using logistic regression. RESULTSLow birth weight, being a twin or triplet, mother being a diethylstilbestrol-daughter, fertility treatments, paternal subfertility, obesity, prescriptive drug use, and familial occurrence of hypospadias or testicular cancer were associated with hypospadias in general. For familial occurrence of hypospadias, there were high risk estimates for the distal and middle phenotypes with an OR (95%CI) of 10.4 (4.5-24.1) and 9.0 (3.1-26.0), but not for the proximal type at 1.8 (0.2-14.9). By contrast, the association with low birth weight (a proxy for placental dysfunction) seemed much stronger for proximal hypospadias with an OR (95%CI) of 9.1 (3.4-24.2) compared with distal and middle hypospadias at 2.6 (1.4-5.0) and 2.3 (0.8-6.5). There were similar estimates for pre-eclampsia. CONCLUSIONThese findings indicate aetiological heterogeneity of hypospadias and provide indications for the possible mechanisms through which specific risk factors may interfere with penile development. KEYWORDShypospadias, risk factors, endocrine disruptors, phenotype, severity Study Type -Aetiologic (case-referent) Level of Evidence 2a OBJECTIVETo obtain more insight into the origin of hypospadias by exploring a wide range of potential risk factors in a case-referent study in which a distinction was made between different phenotypes. PATIENTS AND METHODSCases and referents were 305 boys with hypospadias and 629 boys with middle ear effusion whose parents completed postal questionnaires. Hypospadias phenotype was classified as distal (195 boys), middle (67),

The leading cause of end-stage renal disease in children is attributed to congenital anomalies of the kidney and urinary tract (CAKUT). Familial clustering and mouse models support the presence of monogenic causes. Genetic testing is insufficient as it mainly focuses on HNF1B and PAX2 mutations that are thought to explain CAKUT in 5–15% of patients. To identify novel, potentially pathogenic variants in additional genes, we designed a panel of genes identified from studies on familial forms of isolated or syndromic CAKUT and genes suggested by in vitro and in vivo CAKUT models. The coding exons of 208 genes were analyzed in 453 patients with CAKUT using next-generation sequencing. Rare truncating, splice-site variants, and non-synonymous variants, predicted to be deleterious and conserved, were prioritized as the most promising variants to have an effect on CAKUT. Previously reported disease-causing mutations were detected, but only five were fully penetrant causal mutations that improved diagnosis. We prioritized 148 candidate variants in 151 patients, found in 82 genes, for follow-up studies. Using a burden test, no significant excess of rare variants in any of the genes in our cohort compared with controls was found. Thus, in a study representing the largest set of genes analyzed in CAKUT patients to date, the contribution of previously implicated genes to CAKUT risk was significantly smaller than expected, and the disease may be more complex than previously assumed.

No abstract

Hypospadias is a common congenital malformation of the male external genitalia. We performed a genome-wide association study using pooled DNA from 436 individuals with hypospadias (cases) and 494 controls of European descent and selected the highest ranked SNPs for individual genotyping in the discovery sample, an additional Dutch sample of 133 cases and their parents, and a Swedish series of 266 cases and 402 controls. Individual genotyping of two SNPs (rs1934179 and rs7063116) in DGKK, encoding diacylglycerol kinase κ, produced compelling evidence for association with hypospadias in the discovery sample (allele-specific odds ratio (OR) = 2.5, P = 2.5 × 10⁻¹¹ and OR = 2.3, P = 2.9 × 10⁻⁹, respectively) and in the Dutch (OR = 3.9, P = 2.4 × 10⁻⁵ and OR = 3.8, P = 3.4 × 10⁻⁵) and Swedish (OR = 2.5, P = 2.6 × 10⁻⁸ and OR = 2.2, P = 2.7 × 10⁻⁶) replication samples. Expression studies showed expression of DGKK in preputial tissue of cases and controls, which was lower in carriers of the risk allele of rs1934179 (P = 0.047). We propose DGKK as a major risk gene for hypospadias.