Pluripotent stem cells (PSCs; embryonic stem cells and induced pluripotent stem cells) can recapitulate critical aspects of the early stages of embryonic development; therefore, they became a powerful tool for the in vitro study of molecular mechanisms that underlie blastocyst formation, implantation, the spectrum of pluripotency and the beginning of gastrulation, among other processes. Traditionally, PSCs were studied in 2D cultures or monolayers, without considering the spatial organization of a developing embryo. However, recent research demonstrated that PSCs can form 3D structures that simulate the blastocyst and gastrula stages and other events, such as amniotic cavity formation or somitogenesis. This breakthrough provides an unparalleled opportunity to study human embryogenesis by examining the interactions, cytoarchitecture and spatial organization among multiple cell lineages, which have long remained a mystery due to the limitations of studying in utero human embryos. In this review, we will provide an overview of how experimental embryology currently utilizes models such as blastoids, gastruloids and other 3D aggregates derived from PSCs to advance our understanding of the intricate processes involved in human embryo development.

Patent ductus arteriosus (PDA) is frequent in preterm newborns, and its incidence is inversely associated with the degree of prematurity. The first choice of pharmacological treatment is ibuprofen. Several genes, including EPAS1, have been proposed as probable markers associated with a genetic predisposition for the development of PDA in preterm infants. EPAS 1 NG_016000.1:g.84131C>G or rs7557402 has been reported to be probably benign and associated with familial erythrocytosis by the Illumina Clinical Services Laboratory. Other variants of EPAS1 have been previously reported to be benign for familial erythrocytosis because they decrease gene function and are positive for familial erythrocytosis because the overexpression of EPAS1 is a key factor in uncontrolled erythrocyte proliferation. However, this could be inconvenient for ductal closure, since for this process to occur, cell proliferation, migration, and differentiation should take place, and a decrease in EPAS1 gene activity would negatively affect these processes. Single-nucleotide polymorphisms (SNPs) in EPAS1 and TFAP2B genes were searched with high-resolution melting and Sanger sequencing in blood samples of preterm infants with hemodynamically significant PDA treated with ibuprofen at the National Institute of Perinatology. The variant rs7557402, present in the EPAS1 gene eighth intron, was associated with a decreased response to treatment (p = 0.007, OR = 3.53). The SNP rs7557402 was associated with an increased risk of pharmacological treatment failure. A probable mechanism involved could be the decreased activity of the product of the EPAS1 gene.

Background/Objectives: Congenital microcephaly is a clinical manifestation with a heterogeneous etiology, and its epidemiological surveillance relies on the systematic identification of cases and investigation of their underlying causes to inform preventive strategies and improve prognostic assessments. In Latin America, despite the existence of congenital anomaly reporting programs since 1967, the surveillance of microcephaly only gained substantial attention following the Zika virus (ZIKV) epidemic in 2015. Since then, efforts have predominantly concentrated on cases of infectious origin, often at the expense of recognizing endogenous etiologies, particularly those of genetic nature. This review aims to examine the role of genetic alterations in microcephaly pathogenesis and evaluates the limitations of current surveillance systems. Methods: A literature review centered on syndromic and non-syndromic genetic etiologies, alongside an analysis of Latin American surveillance frameworks (ECLAMC, RyVEMCE, ICBDSR, ReLAMC) was performed. Results: The findings reveal improved case detection and increased reported prevalence; however, the proportion of genetically attributed cases has remained stable. No systematic studies were found identifying the most common genetic causes; instead, genetic investigations were limited to isolated cases with a family history. Conclusions: While epidemiological surveillance systems in Latin America have advanced in the reporting of congenital microcephaly cases, substantial gaps remain in case ascertainment and etiological investigation, particularly concerning genetic contributions

Gestational weight gain (GWG) and birth weight (BW) have a multifactorial etiology, which makes identifying the most influential determinants difficult. The association between variants of the FTO and LEPR genes has been explored as contributing factors to obesity in various age groups; however, their role in GWG and BW in adolescent mothers and their offspring is uncertain. To determine whether the presence of polymorphisms rs9939609 (FTO) and rs1137101 (LEPR) is associated with gestational weight gain and newborn weight in a cohort of adolescent mothers. Methods: A prospective cohort study of 305 mother-child dyads was conducted between 2020 and 2024. Genotyping of the single nucleotide variants (SNVs) rs9939609 of the FTO gene and rs1137101 of the LEPR gene was performed using real-time PCR and high-resolution melting analysis (qPCR-HRM), using maternal peripheral blood and umbilical cord blood samples. GWG, BW, energy intake, and other perinatal data were recorded and classified. Genetic data from 305 mother–offspring dyads were analyzed. The median maternal age was 16 years, and 71.4% had a normal pre-pregnancy body mass index (BMI). The most frequent genotypes were TT for FTO rs9939609 and AG for LEPR rs1137101. In both groups, the genotypic distribution significantly deviated from Hardy–Weinberg equilibrium (p < 0.0001). The AA genotype of FTO was associated with a higher probability of excessive gestational weight gain (GWG) after adjustment for pre-pregnancy BMI and dietary and sociodemographic factors. High protein and lipid intake increased the risk of excessive GWG, whereas adequate intake of carbohydrates and legumes showed a protective effect. An initial significant association was identified between the LEPR rs1137101 variant (AA allele) and low birth weight (LBW); however, this association was lost after adjustment for confounding factors. The FTO rs9939609 variant was significantly associated with GWG. On the other hand, the LEPR rs1137101 variant in the offspring showed an association with BW categorized by percentiles (in crude analysis), while the FTO variant showed no relationship with birth weight.