N-acetyltransferase 2 (NAT2) catalyzes the bioactivation and/or detoxification of drugs and carcinogens. The aim of this study was to establish the correlation between the NAT2 genotype and the acetylating phenotype in a Mexican population using sulfamethazine as a probe. From a total of 122 individuals, 73 (59.8%) were slow and 49 (40.2%) were fast acetylators. Eleven individuals (9%) had the wild-type genotype (NAT2*4/NAT2*4). The most frequent genotype was NAT2*4/NAT2*5B observed in 20.66% of individuals. In conclusion, our results show that an accurate prediction of the acetylation phenotype by genotyping can be achieved in around half of the population. Further studies with a larger number of individuals are required to establish correlations between phenotype and genotype in half of that patients having a genotype combined with slow/rapid alleles.

ABSTRACT. The acetylating activity of N-acetyltransferase 2 (NAT2) has critical implications for therapeutics and disease susceptibility. To date, several polymorphisms that alter the enzymatic activity and/or protein stability of NAT2 have been identified. We examined the distribution and frequency of NAT2 genotypes in the Mexican population. Among 250 samples amplified and sequenced for the NAT2 gene, we found seven different SNPs; the most frequent allele was 803 A>G (35.8%), followed by 282 C>T, 341 T>C, and 481 C>T. There were no differences in the distribution of SNPs between healthy subjects and cancer patients. These eight polymorphisms defined 26 diplotypes; 11.6% were wild type (NAT2*4/NAT2*4), while the most common diplotype was NAT2*4/NAT2*5B, present in 17.2%. We did not identify other common polymorphisms. The results were compared with the NAT2 SNPs reported from other populations. All but the NAT2 genotypes in MexicansTurkish population was significantly different from ours. We conclude that the mixed-race Mexican population requires special attention because NAT2 genotype frequencies differ from those in other regions of the world.

We report on a 16-year-old girl with a complex phenotype, including intellectual disability, facial dysmorphisms, and obesity. During her infancy, she presented with weak sucking, global developmental delay, and later with excessive eating with central obesity. The girl was clinically diagnosed with probable Prader-Willi syndrome. Chromosomal analysis showed a de novo deletion 46,XX,del(15)(q21q22). However, the use of the Affymetrix CytoScan HD Array defined the exact breakpoints of the deleted 15q21q22 region. The imbalance, about 10.5 Mb in size, is to date the second largest deletion ever described in this chromosomal region. In addition, our patient carries a microdeletion in the 1q44 region and a gain in 9p24. The array result was arr[hg19] 9p24.1(6,619,823-6,749,335)×3, 1q44(248,688,586-248,795,277)×1, 15q21.2 q22.2(50,848,301-61,298,006)×1. Although our patient presents additional chromosomal alterations, we provide a correlation between the clinical findings and the phenotype of the 15q21 deletion syndrome.