RESUMEN
INTRODUCTION: Cleft lip and palate (CLP) is a common congenital anomaly characterized by incomplete fusion of the lip and/or palate during embryonic development. The etiology of CLP is multifactorial, involving genetics and different environmental factors. The methylenetetrahydrofolate reductase (MTHFR) gene has been proposed as a candidate gene associated with CLP due to its involvement in folate metabolism and DNA methylation processes. However, the association between MTHFR gene variants and CLP in non-syndromic patients in the North Indian population remains unclear. AIM AND OBJECTIVES: This research aimed to see the association between MTHFR gene polymorphisms in non-syndromic patients with CLP in the North Indian population. MATERIALS AND METHOD: A case-control observational design comprised 50 CLP patients (cases) and 50 healthy individuals without CLP (controls). Blood samples were collected from patients visiting two hospitals. Genomic DNA was extracted from collected peripheral blood samples, and the genotyping of MTHFR gene polymorphisms (specifically, C677T) was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The allelic and genotypic frequencies of MTHFR gene variants were compared between cases and controls using appropriate statistical tests. RESULT: This research revealed a significant association between MTHFR gene polymorphism and CLP in the North Indian population. The odds for the genotypes reach statistical significance, suggesting that the MTHFR gene variant may play a major role in this population's susceptibility to non-syndromic CLP. CONCLUSION: This study provides evidence for a linkage between the MTHFR gene C677T polymorphism and an increased risk of CLP in non-syndromic patients in the North Indian population. These findings do support the involvement of MTHFR gene variants in the etiology of CLP. In the future, more research is warranted to elucidate the underlying mechanisms linking MTHFR gene variants to CLP and to explore potential gene-environment interactions in this context.
RESUMEN
Hypodontia (tooth agenesis) is regarded as the most common congenital dental anomaly. The present review discusses the epidemiological characteristics of congenitally missing second permanent molars (CMSPMs) within a systematic review of the literature. The review was based on Pubmed library associated with the search of various scientific databases or academic resources, improved by hand search of reference lists. The terms 'hypodontia' or 'anodontia' in combination with 'prevalence' or 'epidemiology' were searched in the data sources for studies published between January 2001 and December 2020. Abstracts of non-English papers were also analyzed. The inclusion criteria were as follows: i) Study provided precise data about CMSPMs, even if no second permanent molar was reportedly missing; ii) the number of CMSPMs distributed by jaw was provided and iii) studies on subjects >3 years were used. The exclusion criteria were as follows: i) Studies on patients with history of trauma of the maxilla or the mandible, any type of syndrome affecting bone metabolism, metabolic disorders, previous extraction or tooth loss due to dental caries, cleft lip and palate; ii) studies performed on cohorts of patients with hypodontia and iii) studies reporting data including third molars, except for those that presented sufficient data to perform correct calculations. A total of 79 studies were selected, accumulating a population of 281,968 people, with an average sample size of 3,524.60±11,255.25. The prevalence of CMSPMs (IpHSPM) was 2.79±3.16% among all missing teeth (1.03±1.59% for upper CMSPMs and 1.76±2.32% for lower CMSPMs; P=0.011). There were no significant differences (P=0.250) in IpHSPM between men (1.59±1.52%) and women (2.13±1.67%). However, significant differences were recorded between continents. Furthermore, lower CMSPMs were found more frequently in orthodontic samples (P=0.033). The prevalence of CMSPMs is low compared with the overall prevalence of CM teeth. Despite the rarity of these anomalies, early detection is important to enable practitioners to plan and start treatment at the best time for optimal results.