Biogeographical origin and timing of the founder ichthyosis TGM1 c.1187G > A mutation in an isolated Ecuadorian population
Esperón Moldes, Uxía Saraiva; Pardo Seco, Jacobo José; Montalván-Suárez, M.; Fachal Vilar, Laura; Ginarte Val, Manuel Javier; Rodríguez Pazos, Laura; Gómez Carballa, Alberto; Moscoso, F.; Ugalde-Noritz, N.; Ordoñez Ugalde, Andrés; Tettamanti-Miranda, D.; Ruiz, J. C.; Salas Ellacuriaga, Antonio; Vega Gliemmo, Ana
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Identificadores
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Fecha de publicación
2019Título de revista
Scientific Reports
Tipo de contenido
Artigo
DeCS
transglutaminasas | genotipo | secuencias repetidas en tándem | análisis de componentes principales | humanos | haplotipos | ictiosisMeSH
Humans | Transglutaminases | Ichthyosis | Haplotypes | Principal Component Analysis | Tandem Repeat Sequences | GenotypeResumen
An unusually high frequency of the lamellar ichthyosis TGM1 mutation, c.1187G > A, has been observed in the Ecuadorian province of Manabi. Recently, the same mutation has been detected in a Galician patient (Northwest of Spain). By analyzing patterns of genetic variation around this mutation in Ecuadorian patients and population matched controls, we were able to estimate the age of c.1187G > A and the time to their most recent common ancestor (TMRCA) of c.1187G > A Ecuadorian carriers. While the estimated mutation age is 41 generations ago (~1,025 years ago [ya]), the TMRCA of Ecuadorian c.1187G > A carrier haplotypes dates to just 17 generations (~425 ya). Probabilistic-based inferences of local ancestry allowed us to infer a most likely European origin of a few (16% to 30%) Ecuadorian haplotypes carrying this mutation. In addition, inferences on demographic historical changes based on c.1187G > A Ecuadorian carrier haplotypes estimated an exponential population growth starting ~20 generations, compatible with a recent founder effect occurring in Manabi. Two main hypotheses can be considered for the origin of c.1187G > A: (i) the mutation could have arisen in Spain >1,000 ya (being Galicia the possible homeland) and then carried to Ecuador by Spaniards in colonial times ~400 ya, and (ii) two independent mutational events originated this mutation in Ecuador and Galicia. The geographic and cultural characteristics of Manabi could have favored a founder effect that explains the high prevalence of TGM1 c.1187G > A in this region.
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