Prevalence and risk factors for Down syndrome: A hospital-based single-center study in Western Mexico.

Although Hispanics of Mexican origin in the United States have been identified as a population with a particularly higher rate of Down syndrome (DS), there is a paucity of studies concerning this topic in Mexico. The aim of this study was to determine the prevalence and risk factors for DS in a population from Western Mexico. For prevalence, 230 liveborn infants with DS were included from a total of 89,332 births occurring during the period 2009-2017 at the Dr. Juan I. Menchaca Civil Hospital of Guadalajara (Mexico). In order to evaluate potential DS risks, a case-control study was conducted among 633 newborns, including those 211 DS patients with full trisomy 21 (cases) and 422 infants without birth defects (controls). Data were analyzed using multivariable logistic regression analysis. The overall prevalence for DS was 25.7 per 10,000 (95% confidence interval [95% CI]: 22.4-29.1). Patients with DS had a significantly higher risk for family history of DS in distant relatives (adjusted odds ratio [aOR] = 4.4, 95% CI: 2.5-7.7), relatives with thyroid disease (aOR = 2.3, 95% CI: 1.2-4.0), maternal age ≤ 19 years (aOR = 5.1, 95% CI: 2.7-9.6) or ≥ 35 years (aOR = 3.3, 95% CI: 1.5-6.9), paternal age ≤ 19 years (aOR = 3.5, 95% CI: 1.7-7.4), pre-pregnancy BMI ≥ 25 kg/m2 (aOR = 1.6, 95% CI: 1.0-2.4), and pre-pregnancy alcohol consumption (aOR = 1.8, 95% CI: 1.1-2.9). The identified risks in family history, and previously mentioned nutritional disadvantages were associated with DS in our sample and probably also to its increased prevalence in our population.

Co-occurrence of hemiscrotal agenesis with cutis marmorata telangiectatica congenita and hydronephrosis affecting the same side of the body.

To our knowledge, there are nine previous reports of patients with congenital scrotal agenesis (CSA), seven of which were bilateral, and unilateral in two, also named as hemiscrotal agenesis (HSA). Here, we report a male infant with the previously undescribed co-occurrence of HSA with cutis marmorata telangiectatica congenita (CMTC), and hydronephrosis due to vesicoureteral reflux, all of them on the left side. CMTC is a segmental vascular malformation usually attributed to mosaicism of a postzygotic mutation, whereas the mechanisms in the CSA involve a failure on the labioscrotal fold (LSF) development due to a localized 5α-reductase deficiency and/or androgen insensitivity. Since the skin with HSA was affected also by CMTC and by the fact that it exhibited lack of response to the topical testosterone treatment, all this suggests to us an androgen insensitivity mosaicism in our patient restricted to the left LSF, because skin with intact androgen receptors normally shows some type of response. Since CSA and/or HSA have been also seen in patients with PHACES, popitleal pterygium syndrome, or as part of a recently proposed familial entity with CSA (or agenesis of labia majora as its female counterpart), developmental delay, visual impairment, and moderate hearing loss, further reports could confirm this manifest genetic heterogeneity, highly evocative of somatic mosaicism in our patient.