Fig. 1.

Genetic analysis of cases 1 and 3. a Genomic DNA sequences of VPS33B. Compound heterozygous mutations in VPS33B [NM_018668.4:c.403+2T>A in intron 6 and c.1582-9C>G in intron 20] were identified. The black arrows indicate exon–intron boundary. b cDNA sequence of VPS33B. Mutant mRNA derived from lymphocytes showed an insertion of an 8-bp intronic sequence after exon 20, resulting in a premature stop codon. c Western blot analysis of VPS33B expression. VPS33B expression was not detected in patients’ lymphocytes using the VPS33B antibody (sc-398322, Santa Cruz), which recognizes amino acids 271–570 of VPS33B. d Genomic DNA sequences of VIPAS39. Compound heterozygous mutations in VIPAS39 {[NM_001193314.1:c.339del p.(Phe113Leufs*60)] and [NM_001193314.1:c.1035C>G p.(Tyr345*)]} were identified.