Figure 2.

Pedigrees and proband's phenotype in OI families. (A) Family 3: the three generation pedigree of a family diagnosed with inherited dentin defects that follow an autosomal dominant pattern of inheritance. The dental phenotype was typical of dentinogenesis imperfecta, with variable discoloration of the permanent dentition, abnormal pulp size, and bulbous molar crown morphology. The cause of this phenotype was discovered during whole‐exome sequence analyses to be a dominant mutation in the first codon of exon 34 in COL1A2: c.2027G>A; p.Gly676Asp. Sanger sequencing chromatograms from exon 34 of COL1A2 show that the proband (III:1; left) and her similarly affected younger brother (III:2; middle) were heterozygous for this mutation, while the unaffected brother (III:3; right) did not carry the mutant allele. (B) Family 4: mild dentin defects in the primary dentition of a simplex case. No potential disease‐causing mutations were detected in DSPP. (C) Family 5: a second simplex case of inherited dentin defects in the absence of any DSPP defects. The dentition is severely discolored, with bulbous crowns, constricted cervical areas, pulp obliteration, and thin narrow roots. No disease‐causing mutation was evident by the whole‐exome sequence analysis. An asterisk in the pedigree marks persons who were recruited for the study and contributed DNA samples. OI, osteogenesis imperfecta; COL1A2, collagen type I alpha 2; DSPP, dentin sialophosphoprotein.