FIGURE 1.

Diagnosis of ATP6AP1‐CDG in the siblings. The patients P1, A and P2, B both presented with persistent hyperbilirubinemia, hepatosplenomegaly, and cutis laxa, which in P2 disappeared after 6 months. Isoelectric focusing of serum transferrin, C and apolipoprotein C‐III, D, in the boys showed abnormal profiles consistent with a combined defect of N‐ and O‐glycosylation (numbers on the left indicate the number of sialic acid residues attached to the individual glycosylated forms of TF/ApoC‐III). Analysis by whole‐exome sequencing in P1, E, identified a hemizygous variation c.221T>C (p.L74P) in ATP6AP1 gene, which was also heterozygously present in the mother. Sanger sequencing of ATP6AP1 found the same mutation in P2, F. Distribution of this mutation in the affected family is shown in the pedigree chart, G