Exome sequencing revealed that the girl was heterozygous for a missense mutation (c.1651A>G, p.Ile538Val) in exon 13 of FGFR3, a known mutation for hypochondroplasia, inherited from her mother.
Amino acid substitutions Asn540Lys, Asn540Thr and Ile538Val in the fibroblast growth factor receptor 3 (FGFR3) are considered to cause hypochondroplasia.
It is difficult to establish whether the Ile538Val substitution is rare in hypochondroplasia patients or whether the individuals, who have a moderate degree of short stature, rarely seek medical help for the short stature and consequently are rarely diagnosed as affected by hypochondroplasia.