Histopathology of fetal diastrophic dysplasia

Fetal Skeletal Dysplasias: Radiologic-Pathologic Classification of 72 Cases

ObjectiveThe aim of this study was to classify the fetal skeletal dysplasias (FSD) in a series of affected fetuses based on radio-pathologic criteria. Materials and methods: We gathered clinicopathologic data of 72 cases which were diagnosed among 5995 autopsies performed over a 8-year period. Results: The prevalence of FSD was 1.2:100 autopsies. The overall sex ratio (M:F) was 1.25. Gestational age was between 17 and 24 weeks in 60% of cases. The FSD were classified into 13 distinct pathologic groups. Four major groups were identified: (1) Osteogenesis imperfecta (21 cases, 29%); (2) FGFR3 chondrodysplasia (18 cases, 25%); (3) Ciliopathies (9 cases, 12%); and (4) Sulfation disorders (7 cases, 10%). Thanatophoric dysplasia type 1 and lethal osteogenesis imperfecta were the most common skeletal dysplasias. Conclusion: Our study demonstrates the usefulness of the radio-pathologic examination in the diagnosis and accurate classification of the FSD, thus enabling better targeting of genetic counseling.

Prenatal diagnosis of diastrophic dysplasia in the second trimester of pregnancy: Two- and three- dimensional ultrasonographic findings

To present a prenatal diagnosis of diastrophic dysplasia in the second trimester of pregnancy using two- (2D) and three-dimensional (3D) ultrasonography. The mother was primigravida and aged 12 years. She underwent the first 2D obstetric ultrasound examination at 27 weeks, showing bilaterally upper and lower limb micromelia, thumb and hallux in bilateral abduction, bilateral talipes equinovarus; hyperlordosis of the lumbar spine, cervical, lumbar, and sacral scoliosis; cervical hyperkyphosis with the misalignment of cervical vertebrae, and straight clavicles. 3D ultrasonography in conventional and HDlive rendering modes confirmed the changes observed in 2D ultrasonography and allowed improved understanding by the parents. At birth, the newborn presented transient respiratory distress and neonatal sepsis. At the time of writing, the child is aged 31 months and under follow-up by the pediatrics department. 3D ultrasound allowed the parents to understand the fetal malformations better, and they received adequate counseling.

Atelosteogenesis type 2

Atelosteogenesis type 2 (AO2) (MIM 256050) is a neonatally lethal chondrodysplasia characterised by severe limb shortening and deficient ossification of parts of the skeleton. Other features include facial dysmorphism, cleft palate, talipes, and abducted thumbs and toes. Phenotypic overlap with non-lethal diastrophic dysplasia (DTD) suggested a common aetiology and it has recently been confirmed that both syndromes result from mutations in the DTDST (diastrophic dysplasia sulphate transporter) gene.

Pseudodiastrophic dysplasia type Burgio in a newborn

Pseudodiastrophic dysplasia is a distinct disorder that differs from diastrophic dysplasia on the basis of elbow and proximal interphalangeal joint dislocations, platyspondyly, and scoliosis. We report on a new patient with this rare skeletal dysplasia and two previously undescribed major malformations: omphalocele and complex heart defect.

A chondrodysplasia family produced by mutations in the diastrophic dysplasia sulfate transporter gene: genotype/phenotype correlations

Achondrogenesis type 1B (ACG-1B), atelosteogenesis type 2 (AO-2), and diastrophic dysplasia (DTD) are recessively inherited chondrodysplasias of decreasing severity caused by mutations in the diastrophic dysplasia sulfate transporter (DTDST) gene on chromosome 5. In these conditions, sulfate transport across the cell membrane is impaired which results in insufficient sulfation of cartilage proteoglycans and thus in an abnormally low sulfate content of cartilage. The severity of the phenotype correlates well with the predicted effect of the underlying DTDST mutations: homozygosity or compound heterozygosity for stop codons or transmembrane domain substitutions mostly result in achondrogenesis type 1B, while other structural or regulatory mutations usually result in one of the less severe phenotypes. The chondrodysplasias arising at the DTDST locus constitute a bone dysplasia family with recessive inheritance.

Prenatal diagnosis of osteochondrodysplasias in high risk pregnancy

We collected data on 39 prenatally diagnosed osteochondrodysplasias. We detected 30 (76.9%) cases in the first and second trimesters, including 18 (46.2%) with two twins before the 24th week of gestation. Of 39 cases 11 (28.2%) had osteogenesis imperfecta (OI) type II. Verification of the prenatal diagnosis was attempted in 26 cases on the basis of the data obtained from ultrasonographs, radiographs, external examination, and autopsy protocols. The prenatal diagnosis was confirmed in 19 (73%) fetuses. In 13 cases verification was not possible because one or several investigations could not be performed. Counselling followed all identified cases with osteochondrodysplasia. We present the pedigree of two families indicating the possibility of early prenatal diagnosis of achondrogenesis type I and metatropic dysplasia. We propose indications for ultrasonographic anatomical screening with subsequent phenotype analysis in high risk pregnancy to provide for the prenatal detection of malformations and hereditary diseases.