Conclusion
Joint involvement and recurrent infections with hypogammaglobulinemia
are variable in LRBA deficiency, hence it should always be kept in mind
as a differential diagnosis for a patient with these conditions. In this
case, arthritis was the first presenting condition followed by
pneumonia, and according to the episodes of recurrent infection,
hypogammaglobulinemia, and poor response to immunizations, CVID was
suggested as the possible diagnosis. Fecal calprotectin level was
increased during bacterial infection and as disease severity increased.
This being considered, fecal calprotectin level may be a useful marker
for application in children with LRBA deficiency during infectious
diarrhea. In this patient, we found two novel mutations in two different
gene loci (TCF3 and LRBA ) which were both classified asVariant of Uncertain Significance (VUS) . Validation of these
detected variants by another molecular method such as PCR-Sanger
sequencing is recommended. Also, more effort should be made to resolve
VUS classification as pathogenic or benign. This can be achieved by
investigating and functional analysis of these variants in a sufficient
number of families. Based on this analysis, a more accurate
classification of variants could be reached.