TITLE:
Genetic Profiling to Assess Susceptibility to Tuberculosis Disease in a Pilot Study with Bulgarian Patients
AUTHORS:
Elena Georgieva, Albena Todorova, Anastasia Ormandjieva, Bozhana Naidenova, Boryana Dankova, Veselina Teneva
KEYWORDS:
Tuberculosis, Polymorphisms, NRAMP1
JOURNAL NAME:
Journal of Tuberculosis Research,
Vol.13 No.1,
March
7,
2025
ABSTRACT: The research project aims to perform genetic profiling in Bulgarian patients with latent or active tuberculosis (TB) and assess the influence of genetic polymorphisms on disease susceptibility and severity. The gene NRAMP1 (Natural resistance-associated macrophage protein 1), also known as SLC11A1 (solute carrier family 11 proton-coupled divalent metal ion transporter membrane 1), encodes a divalent ion channel (Fe2⁺ and Mn2⁺) in the lysosomal membrane. Mutations in this gene have been associated with susceptibility to infectious diseases, including tuberculosis. The genetic profiling conducted in the current research includes the isolation of high-molecular-weight genomic DNA from venous blood, amplification of target genetic markers by polymerase chain reaction (PCR), followed by restriction fragment length polymorphism (RFLP) analysis, and genotype interpretation. Statistical analysis of the data was performed using SPSS v.20, along with case-control and family-based association studies utilizing Plink version 1.07. The study includes 45 samples from 10 families: 27 children and 16 parents. Among them, 13 were healthy, while 32 had active tuberculosis or relapsed. An additional 50 healthy controls were included. The main forms of pulmonary involvement observed were tuberculosis of intrathoracic lymph nodes (TITLV), primary tuberculosis complex (PTK), infiltrative-pneumonic form (IPF), tuberculous meningitis (TM), and latent tuberculosis infection. Of the investigated NRAMP1 polymorphisms—INT4 (rs3731865), D543N (rs17235409), and 3’UTR (rs17235416)—D543N and 3’UTR were found to be normal. For INT4, 17 patients (39.5%) exhibited a normal genotype, 19 (44.3%) were heterozygous (INT4 GC), and 7 (16.2%) were homozygous (INT4 CC). No statistical significance was found for the predisposing effect of NRAMP1 INT4 polymorphism on the development of tuberculosis (p = 0.335). However, the greater frequency of the INT4 GC heterozygous genotype in the patient group (GF = 0.4) compared to the healthy control group (GF = 0.3) indicated a probable predisposing effect.