A linkage map spanning the locus for diastrophic dysplasia (DTD)

Diastrophic dysplasia (DTD) is an autosomal recessive osteochondrodysplasia. Patients have short-limbed short stature and suffer from generalized joint dysplasia. We have recently mapped DTD to the distal long arm of chromosome 5. Here we report the localization of DTD in relation to 16 polymorphic markers on distal 5q. No recombinations occurred with two loci, D5S72 and D5S66. One presumptive candidate gene, osteonectin (SPARC), could be excluded on the basis of three recombinations with the DTD locus. Multipoint linkage analysis performed against a fixed order of markers placed DTD between glucocorticoid receptor (GRL) and SPARC favored by the odds of 33:1 over the next best location of DTD between D5S72 and D5S55. The sex-averaged distance between the definite flanking markers, GRL and D5S55, is 17.5 cM. From previously reported data on the physical localization of markers, we conclude that the DTD locus is in 5q31-q34.