High prevalence of chitotriosidase deficiency in Peruvian Amerindians exposed to chitin-bearing food and enteroparasites

Abstract

HighlightsCatalytic deficiency of chitotriosidase has a very high frequency in Amerindians highly exposed to chitin from enteroparasites and diet.Mutation frequencies are similar to those found in East Asian populations, and is probably conserved for a founder effect.Such condition precludes the use of CHIT1 as a disease biomarker in South American populations with strong ethnic ancestry.

Dup-24 bp in the CHIT1 Gene in Six Mexican Amerindian Populations

“…We also found a high allelic frequency of the dup-24 bp polymorphism of the CHIT1 gene, the highest reported for ethnic groups living in Mexico and one of the highest among world populations (Lee et al 2007). This observation is in accordance with the primarily Asian origin of the American indigenous groups more than 10,000 years ago (Reich et al 2012) and supports the hypothesis of a selective advantage associated with this gene variant (Lee et al 2007) or a possible founder effect as well as other markers (Manno et al 2014). Although the null clinical significance of the dup-24 bp polymorphism in the CHIT1 gene has been established for some time now (Boot et al 1998;Canudas et al 2001;Piras et al 2007), it has not been determined if there is a clinical significance of the high frequency of homozygosity of dup-24 bp in CHIT1 in Amerindian populations.…”

“…However, one important caveat is the presence of individuals homozygous for dup-24 bp in CHIT1 who will require other biomarkers to follow up on their response to ERT (Guo et al 1995;Lee et al 2007;Manno et al 2014). The identification of this polymorphism should also be useful for establishing genetic relationships between populations.…”

“…Regarding Latin American groups, Peruvian and Mexican populations have been studied. In Peruvian populations, the published homozygosity frequencies are 12% (Peruvian mestizo), 22% (indigenous Amerindian), 26% (Amazonian Amerindian), and 12% (Quechua indigenous) (Manno et al 2014). In Mexican mestizos, the frequency of dup-24 bp has been estimated as 5.56% for homozygosity (Juárez-Rendón et al 2012), with no known frequencies for Mexican Amerindian groups.…”

Chitotriosidase activity as additional biomarker in the diagnosis of lysosomal storage diseases

“…Taking into account the high frequency of dup24bp in the chIT1 gene in European countries [4,[12][13][14][15][16][17][18], its prevalence among the population of Ukraine was assessed by screening of this genetic variant in 622 voluntary donors. In 362 individuals (58.2%) dup24bp in the CHIT1 gene was not detected; in 197 persons (31.7%) the duplications were found in the heterozygous state and in 63 persons (10.1%) -in the homozygous state.…”

“…However, the presence of dup24bp in the chIT1 gene of LSDs patients, on the one hand, can complicate the diagnostic process resulting in incorrect diagnosis and, on the other hand, can make it impossible to use chitotriosidase activity as a biomarker for monitoring the efficacy of enzyme replacement therapy. This problem is of particular importance due to rather high frequency of dup24bp in the European population [4,[12][13][14][15][16][17][18].…”