Pedigrees of families. (A) Family I. The 2 probands (I.2.2 and I.2.3 indicated by red arrows) were studied on several occasions with reproducible neutrophil abnormalities measured. The deceased twin I.2.4 is presumed to have been affected. The probands are homozygous for D26N. No abnormalities were noted in the neutrophils of the heterozygous parents, brother, or maternal uncle. Clinical features of affected individuals are designated by the 4-color filled symbol at the top. Heterozygous carriers are indicated by diagonally filled symbols. Wild-type individuals are indicated by open symbols. Open symbols in gray represent untested family members. A symbol with a diagonal line indicates a deceased family member. (B) Stomatitis with severe oral stenosis in patient I.2.3. (C) Family II. Patient II.2.2 was originally reported in 1978,¹⁰  at which time many studies were performed as reported. Because no DNA from her was recoverable, her genotype was inferred from her parents and sibling. She is presumed to have been compound heterozygous for delK7 and V424M. (D) Stomatitis in patient II.2.2. (E) Family 3. Patient III.2.2 was compound heterozygous for L286V and G121R, which are presumed to reside on different alleles by virtue of only 1 allele being found in the mother. The clinically affected brother, III.2.1, was not available for genetic study. (F) Molecular modeling of human Aip1 based on S cerevisiae Aip1/UNC78 shows a dual β-propeller, comprised of an N-terminal propeller (lower) and a C-terminal propeller (upper). Each propeller consists of 7 blades, labeled 1 to 7 in the N-terminal propeller and 8 to 14 in the C-terminal peptide. Each blade consists of a twisted β-sheet comprised of 4 antiparallel strands (A-D). The N terminus of the peptide (shown in blue) traverses the hinge region and forms the D strand of blade 14 (shown in red), conferring rigidity to the open “clamshell” structure. Each of the mutations identified have been superimposed on the images.