Determination of the Population Allelic Frequency of the Variants of the MPS Complex in Southwestern Colombia

Abstract Mucopolysaccharidoses are lysosomal storage diseases characterized by the excessive accumulation of glycosaminoglycan sulfate in organs and tissues. To determine the population allelic frequency of the MPS complex variants in a population without clinical and molecular diagnosis of MPS. An observational descriptive study was carried out where the allelic frequency of variants presents in the IDUA, IDS, SGSH, NAGLU, HGSNAT, GNS, GALNS, GLB1, ARSB, GUSB, HYAL1 genes was determined by means of the sequencing of 320 exomes from patients without a clinical diagnosis of MPS; the results were tabulated, and allelic frequency formulas were used to determine the values associated with each of the genes. 509 alleles associated with the MPS complex were reported, of which 262 have not been previously reported. Genes with the most frequent allelic presence were IDUA, GLB1 and GALNS, involved in MPS I and MPS IV A / B. The total frequencies ranged between 0.00393 (2 alleles) and 0.47937 (248 alleles). These studies make it possible to determine polymorphisms that circulate in the country, present in patients not affected with MPS, allowing to expand the knowledge about the characteristics of the alleles that are present in affected patients.

Variantes del Complejo MPS en población Colombiana / Variants of the MPS Complex in the Colombian population

Introducción: Las Mucopolisacaridosis (MPS) son enfermedades de depósito lisosomal que se caracterizan por la acumulación excesiva de sulfato de Glucosaminoglicanos (GAGs) en órganos y tejidos, debido a la alteración en los genes que codifican para enzimas involucradas en la degradación lisosomal de glucosaminoglicanos. Se reconocen siete tipos distintos de trastornos de MPS (I, II, III, IV, VI, VII y IX) con 11 deficiencias específicas de enzimas lisosomales. El país no tiene datos exactos sobre la carga de la enfermedad, ni datos de frecuencia alélica que permita conocer la presencia de variantes poblacionales y posibles individuos afectados y portadores. Objetivo: Determinar la frecuencia alélica poblacional de las variantes del complejo MPS en una población sin diagnóstico clínico y molecular de esta patología. Materiales y métodos: Estudio descriptivo observacional donde se determinó la frecuencia alélica de variantes presentes en los genes IDUA, IDS, SGSH, NAGLU, HGSNAT, GNS, GALNS, GLB1, ARSB ,GUSB ,HYAL1, asociados a MPS por medio de la secuenciación de 320 exomas completos de pacientes sin diagnóstico clínico de MPS del Suroccidente Colombiano; los resultados fueron tabulados y fueron utilizadas fórmulas de frecuencia alélica para determinar los valores asociados a cada uno de los genes. Resultados: Se reportaron 509 alelos asociadas al complejo MPS, de las cuales 262 no se habían informado previamente. Los genes con presencia alélica más frecuentes fueron IDUA, GLB1 y GALNS, involucrados en MPS I y MPS IV A / B. Las frecuencias totales oscilaron entre 0,00393 (2 alelos) y 0,47937 (248 alelos). Estos estudios nos permiten conocer la frecuencia poblacional de cada una de las variantes asociadas al complejo MPS, lo que facilita la identificación oportuna de posibles pacientes, y portadores, realizar intervenciones oportunas que incluya además asesoramiento genético. Conclusiones: Con el avance en los métodos diagnósticos genómicos es posible ampliar el conocimiento sobre el impacto de presencia de variantes de los genes asociados al complejo MPS en nuestra población, identificación e instauración de programas integrales que nos acerca a la medicina de precisión.

Introduction: Mucopolysaccharidoses (MPS) are lysosomal storage diseases characterized by the excessive accumulation of glycosaminoglycan sulfate (GAGs) in organs and tissues, due to the alteration in the genes that code for enzymes involved in the lysosomal degradation of glycosaminoglycans. Seven different types of MPS disorders (I, II, III, IV, VI, VII, and IX) are recognized with 11 specific lysosomal enzyme deficiencies. Colombia does not have exact data on the burden of the disease, nor data on the allelic frequency that allows knowing the presence of population variants and possible affected individuals and carriers. Objective: To determine the population allelic frequency of the variants of the MPS complex in a population without a clinical and molecular diagnosis of this pathology. Materials and methods: An observational descriptive study was carried out where the allelic frequency of variants present in the IDUA, IDS, SGSH, NAGLU, HGSNAT, GNS, GALNS, GLB1, ARSB, GUSB, HYAL1 genes associated with MPS was determined by means of the sequencing of 320 exomes from patients without a clinical diagnosis of MPS from the Southwest of Colombia; the results were tabulated and allelic frequency formulas were used to determine the values associated with each of the genes. Results: 509 alleles associated with the MPS complex were reported, of which 262 have not been previously reported. The genes with the most frequent allelic presence were IDUA, GLB1 and GALNS, involved in MPS I and MPS IV A. These studies allow us to know the population frequency of each of the variants associated with the MPS complex, which facilitates the timely identification of possible patients and carriers, and to carry out timely interventions that also include genetic counseling. Conclusions: With the advancement in genomic diagnostic methods, it is possible to expand the knowledge about the impact of the presence of variants of the genes associated with the MPS complex in our population, identification and establishment of comprehensive programs that bring us closer to precision medicine.