Table 3 Summary of SLC4A11 mutations found in families with CHED2.

Family	Nucleotide change	Exon	Protein mutation (Blosum 80 Score; % residue conservation*)	Location in protein
73024	g.2943delTTinsA†	2	p. Arg82ArgfsX33	Amino‐terminal soluble polypeptide with a new sequence FLSMSTLRCRPPTL added after residue Arg82. Most of the cytoplasmic soluble domain and the transmembrane domain are truncated
73026, 73015‡	g.3552G→A§	4	p. Ala160Thr (0; 3%)	Located in the loop connecting two α‐helices from opposite sides of the αβα‐sandwich
73013	g.8118delCT†	13	p. His568HisfsX177	Truncates the transmembrane domain after residue His568 and adds a hydrophilic peptide of 28 residues at the C terminus (RPGDRRAQPPHHAGHALAGLHPLPIQEE)
73026, 73015	g.8298C→T†	14	p. Arg605X	Truncates transmembrane domain at residue Arg605
73035‡	g.8379G→T†	14	p. Glu632X	Truncates transmembrane domain at residue Glu632
73037	g.9044G→A	17	p. Arg755Gln (1; 97%)	Located at the surface of transmembrane helix 9. Might affect interaction of transmembrane helix 9 and cytoplasmic membrane
73014‡	g.9191G→A	17	p. Arg804His (0; 100%)	Located in the loop connecting helices 11 and 12 in the predicted transmembrane domain structure. Mutation changes hydrophobic interaction of methyl groups located in ARG stem with those of P640 (distance increases by 1.2 A). This might change the loop stability
73004	g.9200delTinsGG	17	p. Leu807ArgfsX71	Truncation of the C‐terminal part after residue L807 and after addition of the six‐residue peptide (RAAQGA)
73044, 73029‡	g.9361C→T	18	p. Thr833Met (−1; 91%)	Predicted to be located in transmembrane helix 11. The mutation might destabilise the polar cluster formed by residues Thr833, Gln826, Arg827 and Lys828, and affect the loop stability
7039‡, 7043	g.9469G→A	18	p. Arg869His (0; 94%)	Located at the surface of transmembrane helix 12. Might affect interaction of transmembrane helix 12 and cytoplasmic membrane

*The Blosum 80 substitution matrix is based on a threshold of 80% sequence identity. The percentage residue conservation was calculated by comparing corresponding amino acids in all available members (35) of the SLC4A protein family from the UniProtKB/Swiss‐Prot database.

†Subject to potential nonsense‐mediated decay.

‡These families were not used in linkage analysis.

§A polymorphism that occurs with g.8298C→T (p. Arg605X) in families 73026 and 73015 and was found in an unaffected relative in family 73026.

Note: Mutations were not observed in families 73022 and 73049, both used in linkage analysis.