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Hitch-Hiker’s Thumb
Published in Michael E. Mulligan, Classic Radiologic Signs, 2020
One of the characteristic findings in patients with diastruphic dwarfism (diastrophic dysplasia) is hypoplasia of the first metacarpal. This metacarpal hypoplasia results in a low-set, laterally directed thumb, the hitch-hiker’s thumb. Although this abnormality was emphasized in the 1960 article’ that first described this new type of dwarfism, it was apparently not until 1968 that the term hitchhiker’s thumb was used to describe this peculiar clinical and radiographic finding2.
Genetics
Published in Manoj Ramachandran, Tom Nunn, Basic Orthopaedic Sciences, 2018
Peter Calder, Harish Hosalkar, Aresh Hashemi-Nejad
The Greek root of the term diastrophic means distorted, which aptly describes the ears, spine, joints and feet of patients with diastrophic dysplasia. Diastrophic dysplasia was described by Lamy and Maroteaux in 1960. It is inherited as an autosomal recessive trait and is rare except in Finland. The defect is on chromosome 5 in the gene that codes for a sulphate transporter protein called diastrophic dysplasia sulphate transporter. Histopathology reveals that chondrocytes appear to degenerate prematurely and collagen is present in excess.
Genetic disorders, skeletal dysplasias and malformations
Published in Ashley W. Blom, David Warwick, Michael R. Whitehouse, Apley and Solomon’s System of Orthopaedics and Trauma, 2017
Fergal Monsell, Martin Gargan, Deborah Eastwood, James Turner, Ryan Katchky
Diastrophic dysplasia is an autosomal recessive disorder, occurring secondary to a mutation in the SLC26A2 gene. This results in defective production of a sulphate transporter protein, resulting in abnormalities of cartilage proteoglycan. The genetic mutation is present in approximately 1 in 70 in the indigenous population of Finland, but is rare in the rest of the world, with an estimated incidence of 1:1000000.
Fetal Skeletal Dysplasias: Radiologic-Pathologic Classification of 72 Cases
Published in Fetal and Pediatric Pathology, 2022
Achondrogenesis type 1B was diagnosed based on very severe phenotype including extremely short limbs, narrow thorax, prominent, rounded abdomen, clubfeet and delayed ossification of the vertebral bodies and sacrum. Histologic examination showed non-homogeneous poor cartilage matrix, lacking the classic ground glass appearance with dense collagen rings around the chondrocytes, along with delayed and very poor ossification (Figure 9a–d). The moderate non-lethal form, corresponding to diastrophic dysplasia, was characterized by micromelia, clubfeet and hypoplasia of the first metacarpal that was oval shaped causing abduction of the thumbs (“hitchhiker thumbs”). Histologic examination showed non-homogeneous cartilage pericellular matrix with pale areas, disruption of the proliferative and hypertrophic zones by coarse collagen fibers and irregular invasion of the metaphyseal capillaries (Figure 9e–g).
Prenatal genetic diagnosis of omphalocele by karyotyping, chromosomal microarray analysis and exome sequencing
Published in Annals of Medicine, 2021
Xiaomei Shi, Hui Tang, Jian Lu, Xiue Yang, Hongke Ding, Jing Wu
In this case, omphalocele, cystic hygroma, spinal malformation and short limbs were prenatally diagnosed by ultrasound at 11+3 weeks (Figure 3). Moreover, the woman had two similar pregnancies before. WES showed a heterozygous point variation of the SLC26A2 gene: c.1020_1022delTGT (p.Val341del) from the father and the heterozygosity exon 2–3 deletion from the mother, forming a compound heterozygosity. Mutations in SLC26A2 gene result in a spectrum of autosomal recessive chondrodysplasias that range from the mildest recessive form of multiple epiphysial dysplasia (rMED) through the most common diastrophic dysplasia (DTD) to lethal atelosteogenesis type II and achondrogenesis IB.