Linkage between stature and a region on chromosome 20 and analysis of a candidate gene, bone morphogenetic protein 2

Sib-pair linkage analysis of the quantitative trait, structure, in over 500 Pima Indians indicates that a genetic determinant of governing stature is located on chromosome 20. Analysis of 10 short tandem repeat polymorphisms localized this linkage to a 3.2cM region that includes D20S98 and D20S66. Using all possible sib-pair combinations, linkage was detected to both stature (P = 0.0001) and to leg length (P = 0.001), but not to sitting height. Single-strand conformational polymorphism analysis of exon 3 of the bone morphogenetic protein 2 (BMP2) gene, a candidate gene in this region, in genomic DNA of 20 of the tallest and 20 of the shortest individuals did not show any consistent differences associated with leg length or height. Sequence analysis of the region encoding the mature protein revealed a single nucleotide substitution, a T to G transversion, not detected by single-strand conformational polymorphism (SSCP) analysis. This transversion results in a conservative amino acid substitution of glycine for valine at codon 80 of BMP2. The frequency of this allele was 0.23 in the sample. No significant differences in height were noted in persons carrying either allele. This indicates that this structural alteration is the mature BMP2 protein does not contribute to the differences in stature observed in the Pima Indians, nor is this structural change in the mature protein likely to be responsible for the linkage observed with stature on chromosome 20.