Introduction
IL-12RB1 deficiency is an inborn error of immunity (IEI), it is due to a pathogenic variant with autosomal recessive inheritance, it is classified within Mendelian Susceptibility to Mycobacterial Diseases (MSMD), characterized by defects in immunity mediated by INF-g. Patients are unable to respond adequately against to intracellular pathogens such as M. Bovis (BCG), M. Avium; Salmonella spp. Clinical penetrance is variable from severe manifestations to asymptomatic. We present the clinical case of a patient with IL-12RB1 deficiency, in whom the pedigree was not carried out. Three years later, the pedigree was carried out and two patients and carriers of IL12RB1 deficiency were detected.
Case presentation
She is a 1-year-old female patient, daughter of consanguineous parents and with a history of a sister who died in childhood due to gastrointestinal infection. She received BCG vaccination at birth. Among its clinical manifestations, he had disseminated BCG infection, multiple events of bloody gastroenteritis associated with arthritis and Henoch-Schoenlein purpura, and complicated pneumonia. The diagnosis of IL12RB1 deficiency was confirmed through next generation sequencing (c.1456C>T/ c.1456C>T). Three years after the pedigree was completed, we found 5 carriers (c.1456C>T/WT) and 2 patients (c.1456C>T/c.1456C>T). The first patient, a 2-year-old female with disseminated BCG infection being treated with anti-tuberculosis and the second case, a 25-year-old man with a history of histoplasmosis and adenitis. Both cases were notified of the result and timely medical decisions were made.
Discussion
Carrying out a genetic pedigree after the diagnosis of IL12RB1 deficiency and other IeI must necessarily be carried out. Currently the companies that offer the next generation sequencing services offer these free studies. This case teaches us that we should not limit the genetic study to the index case, but that we should carry out a family tree and carry out the genetic study in the candidates.