3.3 | Mutation studies
Using selective PID panel testing, all patients were found to have
mutations in the CD40LG gene (Table 3 ) and were
diagnosed with XHIGM. In this cohort, hemizygous mutations were found in
five patients (P1, P2, P3, P4, and P7), and microdeletions were found in
two others (P5 and P6). The mutations were mostly inherited via the
maternal lineage (P1, P2, P5, P6, and P7). However, parents of P3 and P4
did not carry the same mutation as their children. Two novel hemizygous
mutations (c.424_436del and c.488delT) in exon 5 were detected in P1
and P3, respectively, whereas a novel hemizygous mutation (c.92_104del)
in exon 1 was found in P2. These mutations have never been reported in
gnomAD and were predicted to be disease-causing mutations using
PolyPhen2, Mutation Taster, PROVEAN, and SIFT software.