Mutations in PIEZO1 gene (exons 45-50) encoding amino acid substitutions in Piezo1 protein extracellular loop. (A) PIEZO1 genotypes observed in Er(a−b+) and Er(a−b−) individuals. PIEZO1 exons 45 to 50 are shown (regions coding for extracellular domain shown in blue). Mutations are highlighted in pink (7180G>A) and yellow (7174G>A), seen in homozygous, heterozygous, and compound heterozygous states in individuals tested as shown. Individual P10 has nonsense mutation in exon 38 (not shown) predicted to encode truncated protein (exons colored gray). (B) PIEZO1 alleles observed in Er variant individuals. PIEZO1 exons 45 to 50 are shown. Mutations are highlighted in purple (7219G>C), green (7219G>A), and brown (6734G>A). All mutations were homozygous in the indicated individuals. (C) All mutations shown in panels A and B encode amino acid substitutions in the extracellular domain of Piezo1 protein (amino acids 2198-2431) as shown (colors as in 2A and 2B).