Missense mutation G296S in GATA4 is not responsible for cardiac septal defects.

BACKGROUND: The most common type of congenital heart disease is the cardiac septal defects, which has reported to be caused by a missense mutation (G296S) in exon 3 of the GATA4 gene. AIMS: The present study was undertaken to find out whether GATA4 gene is the prime cause of the septal defects in Mysore population. MATERIALS AND METHODS: GATA4 gene analyses were undertaken on 21 confirmed CHD cases by PCR and DNA sequencing. RESULTS AND CONCLUSION: Analysis of this particular mutation in 21 septal defect patients revealed that none of the patients had the mutation, indicating that this mutation is population specific or septal defect in Mysore population is caused due to mutations in other regions of the GATA4 gene.

Evolution of phenylthiocarbamide taster trait in Mysore, South India.

BACKGROUND: The ability to taste phenylthiocarbamide (PTC), a bitter chemical has long been known to be a heritable trait, which is being widely used for both genetic and anthropological studies. The frequency of taster and non-taster allele is found to vary in different populations. AIMS AND OBJECTIVE: To investigate the frequency of taster trait in Mysore, South India. MATERIALS AND METHODS: The present investigation was conducted in Mysore, South India during 2002 - 2003. About 3282 subjects irrespective of age, sex, religion, food habits, socio-economic status were randomly selected from various parts of the city and a total of 180 families, which included Christian (50), Hindu (61) and Muslim (69) were screened from different localities of the city. Harris and Kalmus method was used to assess the PTC taster and nontaster phenotype. RESULTS: It was found that tasters were significantly more frequent than nontasters in all the four categories. The incidence of tasters was more in unbiased category (85%) and less in Muslim category (58%). Investigations on PTC tasting in the families of three different religious groups revealed that the tasters were significantly more frequent than nontasters. It was also found that heterozygous father or mother for the taster genes with nontaster partner had taster and nontaster progenies in the ratio 1.0: 1.54 indicating the deviation in the segregation pattern of test cross. CONCLUSION: In Mysore, tasters are more frequent than nontasters. Variation in the frequency of nontaster allele in the religious groups could be due to inbreeding.

An understanding the genetic basis of congenital heart disease.

The recent exponential increase in the knowledge of genetics has revolutionized the understanding of congenital heart diseases (CHDs) during the past few decades. Prior studies have reported the influence of Mendelian disorders on CHDs to be very small, when compared to the polygenic inheritance, which constituted a higher percentage. The recent findings of candidate genes responsible for CHDs have provided new insights into the genetic basis of heart malformation. Here we reviewed the understandings of different types of heart lesions associated with syndromes for which genetic etiologies are apparent, as well as the recent developments involving the molecular pathways involved in CHDs in case of human beings. The similar mutations, which are the devastating events of molecular mechanism, may be the cause of different types of CHDs indicating single gene defects as the cause of different apparent phenotypes. An integrated simple model will explain the causes of presently well known CHDs. This review provides updated information on the genetic basis for cardiac defects which helps to understand, identify, prevent and treat individuals who might be at risk at an early stage. There is a need to find heart defects as early as possible so that they can be treated while the heart is still forming.