Yadav and colleagues43 investigated the interplay between PHOSPHO1 and OPN through the generation of Phospho1–/–; Spp1–/– mice and found a partial rescue of the Phospho1–/– phenotype, with animals at 1 month and 3 months of age exhibiting a reduction in the typical hyperosteoidosis and thoracic scoliosis that characterizes the single knockout animal. The gene discussed is PHOSPHO1; the disease is Thoracic scoliosis.