Figure 1 Sequence analysis of exon 6 of IFNGR1. (A) The genomic DNA of IFNGR1 exon 6 from the patient was amplified by PCR, and the sequence was analysed by direct sequencing. The PCR product was cloned into the pGEM‐T Easy vector. Sequencing analysis detected the presence of the wild‐type (WT) and 774del4 alleles and that the patient had a heterozygous mutation, 774del4 (TCTA), in exon 6 of IFNGR1. (B) Pedigree of this family with the dominant form of IFNγR1 deficiency. Filled symbol, affected person; open symbols, healthy family member. The 774del4 mutation was not detected in either of the parents.