Evidence that polymorphic deletion of the glutathione S-transferase gene, GSTM1, is associated with esophageal atresia

iPSCs derived from esophageal atresia patients reveal SOX2 dysregulation at the anterior foregut stage

A series of well-regulated cellular and molecular events result in the compartmentalization of the anterior foregut into the esophagus and trachea. Disruption of the compartmentalization process leads to esophageal atresia/tracheoesophageal fistula (EA/TEF). The cause of EA/TEF remains largely unknown. Therefore, to mimic the early development of the esophagus and trachea, we differentiated induced pluripotent stem cells (iPSCs) from EA/TEF patients, and iPSCs and embryonic stem cells from healthy individuals into mature three-dimensional esophageal organoids. CXCR4, SOX17 and GATA4 expression was similar in both patient-derived and healthy endodermal cells. The expression of the key transcription factor SOX2 was significantly lower in the patient-derived anterior foregut. We also observed an abnormal expression of NKX2.1 (or NKX2-1) in the patient-derived mature esophageal organoids. At the anterior foregut stage, RNA sequencing revealed the critical genes GSTM1 and RAB37 to be significantly lower in the patient-derived anterior foregut. We therefore hypothesize that a transient dysregulation of SOX2 and the abnormal expression of NKX2.1 in patient-derived cells could be responsible for the abnormal foregut compartmentalization.

Detoxification genes polymorphisms in SIDS exposed to tobacco smoke

The best hypothesis to explain Sudden Infant Death Syndrome (SIDS) pathogenesis is offered by the "triple risk model", which suggests that an interaction of different variables related to exogenous stressors and infant vulnerability may lead to the syndrome. Environmental factors are triggers that act during a particular sensible period, modulated by intrinsic genetic characteristics. Although literature data show that one of the major SIDS risk factors is smoking exposure, a specific involvement of molecular components has never been highlighted. Starting from these observations and considering the role of GSTT1 and GSTM1 genes functional polymorphisms in the detoxification process, we analyzed GSTM1 and GSTT1 null genotype frequencies in 47 SIDS exposed to tobacco smoke and 75 healthy individuals. A significant association (p < .0001) between the GSTM1 null genotype and SIDS exposed to smoke was found. On the contrary, no association between GSTT1 polymorphism and SIDS was determined. Results indicated the contribution of the GSTM1 -/- genotype resulting in null detoxification activity in SIDS cases, and led to a better comprehension of the triple risk model, highlighting smoking exposure as a real SIDS risk factor on a biochemical basis.

Association GSTT1, GSTM1 and GSTP1 (Ile105Val) genetic polymorphisms in mothers with risk of congenital malformations in their children in Western Siberia: a case-control study

OBJECTIVE

Polymorphisms of glutathione S-transferase (GST) genes in mothers may be involved in teratogenesis in their offspring. This study aims to investigate the association of GST genes (T1, M1 and P1) with the risk of having children with congenital malformations (CMs) in residents of the West Siberian region of Russia.

METHOD

We studied 235 women with offspring's with CMs, and 273 women with one or more healthy children. Null genotypes of GSTM1 and GSTT1 were identified through multiplex real-time polymerase chain reaction, and GSTP1 gene (Ile105Val) polymorphism was determined through TaqMan-real-time polymerase chain reaction.

RESULTS

The study showed that the maternal genotype GSTT1 «0/0» is associated with CMs in the offspring (odd ratio (OR) = 3.63, P = 5.18 × 10(-9) ). A significant association of the maternal genotype GSTT1 «0/0» with CMs of the cardiovascular system (OR = 5.03, P = 2.93 × 10(-7) ), urinary system (OR = 4.20, P = 3.51 × 10(-6) ) and central nervous system (OR = 4.40, P = 6.69 × 10(-5) ) was found in the child. No association of maternal GSTM1 (del) and GSTP1 (Ile105Val) genetic polymorphisms with CMs of the child was identified.

CONCLUSION

Homozygous deletion of the GSTT1 gene in women of the West Siberian region is a risk factor for birth defects in the child.

Microdeletion 11q13.1.q13.2 in a patient presenting with developmental delay, facial dysmorphism, and esophageal atresia: possible role of the GSTP1 gene in esophagus malformation

BACKGROUND

Esophageal atresia is a major congenital malformation characterized by a complete interruption of the esophageal continuity. It is frequently observed in associations and syndromes. As an isolated finding, it has a multifactorial etiology whose genetic factors are poorly known. Recently, the GST family, especially the GSTM1 null genotype (but not the GSTP1 polymorphism I105V), has been associated with esophageal atresia. These enzymes play a role in phase II detoxification of xenobiotics. Here we present the clinical and molecular findings observed in a patient suggesting that the loss of the GSTP1 allele might predispose to this malformation.

CASE

We describe a patient presenting with esophageal atresia associated with developmental delay and facial dysmorphism, whose mother used tobacco and alcohol during the first 2 months of her pregnancy. Microdeletion/microduplication analysis was performed using comparative genomic hybridization and a 180K Agilent array. It detected a de novo 2 Mb chromosome 11q13.1.q13.2 deletion.

CONCLUSION

The deleted chromosomal segment includes the GSTP1 gene. We hypothesize that the deletion of one GSTP1 allele (an isoform highly expressed in embryonic tissues), associated with specific environmental factors, such as tobacco and alcohol, could cause the esophageal atresia observed in our patient.

Maternal environmental exposure, infant GSTP1 polymorphism, and risk of isolated congenital heart disease

The GSTP1 gene, highly expressed early in fetal life, is the most abundant phase 2 xenobiotic metabolism enzyme in a human placenta. Fetal inherited GSTP1 Ile105Val polymorphism may modify the metabolism and excretion of xenobiotics from fetal tissue and increase the risk of congenital heart disease (CHD). This study aimed to analyze the joint effects of GSTP1 genetic polymorphism (Ile105Val) and maternal environmental exposure on CHD risk. Within a case-control design, a total of 190 children with CHD (104 boys age 4 ± 5.6 years) and 190 healthy children (114 newborn boys) were genotyped for the GSTP1 Ile105Val polymorphism. Mothers completed a structured questionnaire on the demographics as well as the preconceptional and lifestyle exposures. A higher frequency of mothers of children with CHD (38 %) reported a positive history of exposure to toxicants (occupational and environmental) than mothers of healthy children (23 %) (p = 0.0013). Logistic regression analysis showed that maternal occupational and environmental exposures increased the risk of CHD (odds ratio, 2.6; 95 % confidence interval, 1.6-4.2; p < 0.0001). No significant differences in Ile105Val genotype frequencies were observed between the children with CHD and the healthy children (p = 0.9). Furthermore, case-control analysis showed no evidence of significant interaction between the maternal exposures and GSTP1 polymorphism. Maternal exposure to toxicants increased the risk of children with CHD. However, fetal GSTP1 Ile105Val polymorphism did not increase the risk of CHD.

Knockout and transgenic mice in glutathione transferase research

Glutathione transferases (GSTs) are a multigene family of ubiquitously expressed, polymorphic enzymes responsible for the metabolism of a wide range of both endogenous and exogenous substrates, play a central role in the adaptive response to chemical and oxidative stress, and are subject to regulation by a range of structurally unrelated chemicals. In this review, we present a current summary of knockout mouse models in the GST field, discussing some of the issues pertaining to orthologous proteins between mice and humans, the potential confounding issues related to genetic background, and also cover new transgenic models in the increasingly important area of humanization.