Pointers of  Genetic Susceptibility in an Infant with Pulmonary Tuberculosis

Excerpt

To the Editor: An 8-mo-old boy, a diagnosed case of pulmonary tuberculosis (PTB) presented with features of foreign body; reduced movement and chest expansion on left side with hyperinflation, hyper-resonance notes and crepitation. He had a history of contact with active case of PTB (Grandmother & elder cousin brother). Child received intensive phase anti-tubercular treatment (ATT) for 3 mo. Computed tomography (CT) of chest showed soft tissue density lesions with central necrosis in B/L hilar & para-tracheal lymph nodes with peripheral calcification and soft tissue density lesion in the left main bronchus with hyperinflation of left lung fields. Three samples at different time intervals; two gastric aspirates and one bronchio-alveolar lavage (BAL) fluid revealed acid fast bacilli (AFB) stain and cartridge based nucleic acid amplification test (CBNAAT) positive mycobacterium tuberculosis sensitive to rifampicin and the Lowenstein-Jensen culture was negative. A heterozygous missense variation in exon 7 of the TYK2 gene (chr19:g.10365853C>A;Depth:212x) that results in the amino acid substitution of Histidine for Glutamine at codon 225 (p.Gln225His;ENST00000525621.6) was found. Infant was discharged on three drug ATT and nutritionally recovered with complete resolution of radiological findings at completion of ATT. …