Family pedigree charts of five homozygous Southeast Asian ovalocytosis cases. Families of each homozygous Southeast Asian ovalocytosis (SAO) cases are represented: (A) GO 003/10, (B) GO 001/14, (C) GO 010/10, (D) GO 012/19, and (E) GO 012/13. Squares and circles denote male and females, respectively, with filled ones (grey or black) showing members affected with SAO. The numbered triangle (C) shows number of spontaneous abortions that occurred in the couple’s past pregnancies. Parents of two SAO homozygous children (GO 012/19 and GO 010/10) had multiple unsuccessful pregnancies. The mother of GO 012/19 suffered two intra-uterine deaths (including GO 012/19), while the mother of GO 010/10 suffered three spontaneous abortions. None of these other unsuccessful pregnancies were investigated further. On the other hand, parents of GO 012/13 have two living children among whom one is SAO heterozygous, while parents of GO 012/19 have three living children with unknown SAO status (see the Online Supplementary Table S2). d: died; IUD: intra-uterine death.