Molecular Analysis of a Case of Thanatophoric Dysplasia Reveals Two de novo FGFR3 Missense Mutations located in cis

Prenatal diagnosis of single gene disorders using amniotic fluid as the starting material for PCR

A rapid and inexpensive method for fetal genetic diagnosis using amniotic fluid (AF) as the starting material was demonstrated in this study.

Spondyloepiphyseal dysplasia congenita caused by double heterozygous mutations in COL2A1

Spondyloepiphyseal dysplasia congenita (SEDC) is a group of rare inherited chondrodysplasias characterized by short stature, abnormal epiphyses, and flattened vertebral bodies. SEDC is usually caused by substitution of glycine residue with another amino acid in the triple helical domains of alpha 1 chains, which consist of type II collagen (COL2A1). Herein, we describe a unique case of SEDC with mild coxa vara (SEDC-M) caused by double de novo COL2A1 mutations located on the same allele. One mutation, p.G504S, was previously described in patients with SEDC, whereas the other, p.G612A, was a novel mutation; both were located in the triple helical domain. Neither mutation was identified in the parents and appeared to be de novo. To the best of our knowledge, this is the first study involving a patient with a type II collagenopathy with two COL2A1 mutations on the same allele. The case was characterized by a more severe phenotype compared with previously reported cases involving a single p.G504S mutation, which may have been the result of the double mutation.