Early severe scoliosis in a patient with atypical progressive pseudorheumatoid dysplasia (PPD): Identification of two WISP3 mutations, one previously unreported.

Progressive pseudorheumatoid dysplasia (PPD) is a rare autosomal recessive disorder characterized by spondyloepiphyseal dysplasia associated with pain and stiffness of multiple joints, enlargement of the interphalangeal joints, normal inflammatory parameters, and absence of extra-skeletal manifestations. Homozygous or compound heterozygous WISP3 mutations cause PPD. We report two siblings from a non-consanguineous Ecuadorian family with a late-onset spondyloepiphyseal dysplasia. Mutation screening was undertaken in the two affected siblings using a customized skeletal dysplasia next generation sequencing (NGS) panel and confirmed by Sanger sequencing. Two compound heterozygous mutations were identified in WISP3 exon 2, c.[190G>A];[197G>A] (p.[(Gly64Arg)];[(Ser66Asn)]) in the two siblings, both of which had been inherited. The p. (Gly64Arg) mutation has not been previously described whilst the p. (Ser66Asn) mutation has been reported in two PPD families. The two siblings presented with atypical PPD, as they presented during late childhood, yet the severity was different between them. The progression was particularly aggressive in the male sibling who suffered severe scoliosis by the age of 13 years. This case reaffirms the clinical heterogeneity of this disorder and the clinical utility of NGS to genetically diagnose skeletal dysplasias, enabling adequate management, monitorization, and genetic counseling. © 2016 Wiley Periodicals, Inc.

Identification of a Gypsy SHOX mutation (p.A170P) in Léri-Weill dyschondrosteosis and Langer mesomelic dysplasia.

We report the clinical and molecular characteristics of 12 Spanish families with multiple members affected with Léri-Weill dyschondrosteosis (LWD) or Langer mesomelic dysplasia (LMD), who present the SHOX (short stature homeobox gene) mutation p.A170P (c.508G>C) in heterozygosity or homozygosity, respectively. In all studied families, the A170P mutation co-segregated with the fully penetrant phenotype of mesomelic limb shortening and Madelung deformity. A shared haplotype around SHOX was observed by microsatellite analysis, confirming the presence of a common ancestor, probably of Gypsy origin, as 11 of the families were of this ethnic group. Mutation screening in 359 Eastern-European Gypsies failed to identify any carriers. For the first time, we have shown SHOX expression in the human growth plate of a 22-week LMD fetus, homozygous for the A170P mutation. Although the mutant SHOX protein was expressed in all zones of the growth plate, the chondrocyte columns in the proliferative zone were disorganized with the chondrocytes occurring in smaller columnal clusters. We have also identified a novel mutation at the same residue, c. 509C>A (p.A170D), in two unrelated Spanish LWD families, which similar to A170P mutation impedes nuclear localization of SHOX. In conclusion, we have identified A170P as the first frequent SHOX mutation in Gypsy LWD and LMD individuals.