The genomic locus responsible for Van Buchem's disease is narrowed to an approximately 92 kb region of human chromosome 17 at 17q21. Individuals afflicted with or carriers of Van Buchem's disease exhibit a 52 kb deletion within this 92 kb region. Methods are provided that permit the differentiation between individuals homozygous for and therefore afflicted with Van Buchem's disease, individuals heterozygous for and therefore carriers of Van Buchem's disease, and individuals who are normal with respect to Van Buchem's disease. Also provided are general methodologies for the detection of a wide variety of large genomic deletions.