title: Genotype-phenotype correlation in DTDST dysplasias: Atelosteogenesis type II and diastrophic dysplasia variant in one family.
abstract: Mutations in diastrophic dysplasia sulfate transporter (DTDST) cause a spectrum of autosomal recessive chondrodysplasias. In decreasing order of severity, they include processes designated as achondrogenesis type IB (ACG-1B), atelosteogenesis type II (AO2), diastrophic dysplasia (DTD), diastrophic dysplasia variant (DTDv), and recessively inherited multiple epiphyseal dysplasia (rMED). This is the first report of an extended family with unequivocally distinct phenotypes on the DTDST spectrum. Two siblings have DTDv and their first cousin had AO2. They all share the common Finnish mutation (IVS1 + 2C>T). The two patients with DTDv have the previously reported R279W extracellular domain missense mutation. The second mutation in the patient with AO2 is c.172delA, a deletion of one nucleotide causing a previously unreported frameshift mutation. This is the first published case of an individual with a frameshift mutation combined with the Finnish mutation. These three patients provide an opportunity, in concert with a review of previous literature, to further examine the genotype-phenotype correlation of DTDST. Analysis suggests that, while the DTDST family of disorders contains at least seven different conditions, mutations in the DTDST gene, in fact, appear to cause a phenotypic continuum. Furthermore, DTDST genotype alone is an imperfect predictor of clinical severity along this continuum.
authors.affiliation: Department of Medical Genetics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Ellen
authors.initials: E
authors.lastname: Dwyer
authors.forename: James
authors.initials: J
authors.lastname: Hyland
authors.forename: Peggy
authors.initials: P
authors.lastname: Modaff
authors.forename: Richard M
authors.initials: RM
authors.lastname: Pauli
mesh_terms: D027321:Anion Transport Proteins / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D004392:Dwarfism / Q000235:genetics; D005190:Family; D005260:Female; D016368:Frameshift Mutation; D005808:Genes, Recessive; D056726:Genetic Association Studies; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics; D020125:Mutation, Missense; D010009:Osteochondrodysplasias / Q000000981:diagnostic imaging / Q000235:genetics; D010375:Pedigree; D010641:Phenotype; D011859:Radiography; D017384:Sequence Deletion; D000076988:Sulfate Transporters; D013431:Sulfates / Q000378:metabolism
chemical_list: D027321:Anion Transport Proteins; D026901:Membrane Transport Proteins; C089651:SLC26A2 protein, human; D000076988:Sulfate Transporters; D013431:Sulfates