Recessive MED with auricular swelling due to compound heterozygosity Arg279Tpr/Thr512Lys in the SLC26A2 gene

Esophageal stenosis in an adult Mexican patient with diastrophic dysplasia: Case report

Diastrophic dysplasia (DTD) is caused by biallelic pathogenic variants in the SLC26A2 gene. We report the case of a 49-year-old female with DTD and esophageal stenosis. This broadens the phenotypic spectrum in adult patients with DTD and raises awareness of extra-skeletal manifestations that could develop in later stages of life.

SLC26A2 Related Diastrophic Dysplasia in 42-Years Ukrainian Women

Diastrophic dysplasia (DTD) is an uncommon pathology which falls under the group of skeletal dysplasias with its first symptoms observed from birth. The pathology is often featured by short stature and abnormally short extremities (also known as short-limbed dwarfism); the osseous structures of the body (bones and joints) are characterized through defective development in many body regions. More than 300 genes were reported to be involved in DTD etiology with autosomal recessive, autosomal dominant and X-linked manner. We describe clinical case of a 42-year-old woman from the west of Ukraine with diastrophic dysplasia and two pathogenic variants c.1020_1022del (p.Val341del) and c.1957T>A (p.Cys653Ser) identified in SLC26A2 gene. SLC26A2-related diastrophic dysplasia was confirmed based on the presence of pathogenic variants in SLC26A2, which is associated with autosomal recessive forms of skeletal dysplasia, combined with phenotypic symptoms and radiographic findings.

SLC26A2-Associated Diastrophic Dysplasia and rMED-Clinical Features in Affected Finnish Children and Review of the Literature

Diastrophic dysplasia (DTD) is a rare osteochondrodysplasia characterized by short-limbed short stature and joint dysplasia. DTD is caused by mutations in SLC26A2 and is particularly common in the Finnish population. However, the disease incidence in Finland and clinical features in affected individuals have not been recently explored. This registry-based study aimed to investigate the current incidence of DTD in Finland, characterize the national cohort of pediatric subjects with DTD and review the disease-related literature. Subjects with SLC26A2-related skeletal dysplasia, born between 2000 and 2020, were identified from the Skeletal dysplasia registry and from hospital patient registry and their clinical and molecular data were reviewed. Fourteen subjects were identified. Twelve of them were phenotypically classified as DTD and two, as recessive multiple epiphyseal dysplasia (rMED). From the subjects with available genetic data, 75% (9/12) were homozygous for the Finnish founder mutation c.-26+2T>C. Two subjects with rMED phenotype were compound heterozygous for p.Arg279Trp and p.Thr512Lys variants. The variable phenotypes in our cohort highlight the wide spectrum of clinical features, ranging from a very severe form of DTD to milder forms of DTD and rMED. The incidence of DTD in Finland has significantly decreased over the past decades, most likely due to increased prenatal diagnostics.

Recessive multiple epiphyseal dysplasia - Clinical characteristics caused by rare compound heterozygous SLC26A2 genotypes

Pathogenic sequence variants in the solute carrier family 26 member 2 (SLC26A2) gene result in lethal (achondrogenesis Ib and atelosteogenesis II) and non-lethal (diastrophic dysplasia and recessive multiple epiphyseal dysplasia, rMED) chondrodysplasias. We report on two new patients with rMED and very rare compound heterozygous mutation combinations in non-consanguineous families. Patient I presented in childhood with waddling gait and joint stiffness. Radiographs showed epiphyseal changes, bilateral coxa plana-deformity and knee valgus deformity, for which he underwent surgeries. At present 33 years his height is 165 cm. Patient II presented with cleft palate, small jaw, short limbs, underdeveloped thumbs and on radiographs, cervical kyphosis with an underdeveloped C4. He also developed severe scoliosis but has grown at -2.9 SD curve. Molecular analysis revealed that patient I is heterozygous for two known pathogenic variants in SLC26A2, a splice site variant c.-26+2T > C and a missense variant c.1957T > A (p.Cys653Ser), while patient II is compound heterozygous for missense variants c.835C > T (p.Arg279Trp) and c.1535C > A (p.Thr512Lys). These patients further elucidate the variability of the phenotypic and genetic presentations of rMED.