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Multiple SLC26A2 mutations occurring in a three-generational family
Ana Coral Barreda-Bonis1, Jimena Barraza-García2, Manuel Parrón3
1Skeletal Dysplasia Multidisciplinary Unit (UMDE), Hospital Universitario La Paz, Madrid, Spain; Dept. of Paediatric Endocrinology, Hospital Universitario La Paz, Universidad Autónoma de Madrid, Spain.
Abstract:
Multiple epiphyseal dysplasias (MED) are a group of heterogeneous skeletal dysplasias, which share a common phenotype: short stature, skeletal deformities, joint pain and early onset osteoarthritis. Mutations in COMP account for approximately half of autosomal dominant MED cases whilst SLC26A2 mutations account for ∼25% of the recessive cases in the Caucasian population. We present here an interesting family, which was thought to initially have an autosomal dominant skeletal dysplasia. Using a targeted sequencing skeletal dysplasia panel, the proband was found to be a compound heterozygote for two mutations in SLC26A2, one novel mutation, p.Ser522Phe and the other, the common mutation, p.Arg279Trp. In addition to the classical characteristics of MED, she presented with an atypical feature, bilateral synostoses between the 2nd and 3rd metatarsals. The parents were confirmed to be heterozygous for the two mutations but interestingly, the maternal grandfather, who had MED, was found to be homozygous for the common SLC26A2 mutation.
Insights
Multiple epiphyseal dysplasias (MED) can be caused by SLC26A2 gene mutations. This study identified a novel mutation in a family with MED and atypical skeletal features, expanding our understanding of this genetic disorder.
Area of Science:
- Genetics
- Orthopedics
- Molecular Biology
Background:
- Multiple epiphyseal dysplasias (MED) are a group of skeletal dysplasias characterized by short stature, joint pain, and early-onset osteoarthritis.
- Mutations in the COMP gene are responsible for about half of autosomal dominant MED cases.
- Mutations in the SLC26A2 gene account for approximately 25% of recessive cases in Caucasians.
Observation:
- A family initially suspected of having autosomal dominant skeletal dysplasia was investigated.
- The proband was found to be a compound heterozygote for two SLC26A2 mutations: a novel p.Ser522Phe and the common p.Arg279Trp.
- The proband exhibited classical MED features along with bilateral synostoses between the 2nd and 3rd metatarsals, an atypical presentation.
Findings:
- Genetic analysis revealed compound heterozygosity for SLC26A2 mutations in the proband.
- The proband's parents were heterozygous for the identified SLC26A2 mutations.
- The maternal grandfather, diagnosed with MED, was homozygous for the common SLC26A2 mutation (p.Arg279Trp).
Implications:
- This case expands the known spectrum of SLC26A2 mutations and their associated phenotypes in multiple epiphyseal dysplasias.
- The identification of a novel mutation highlights the importance of comprehensive genetic testing for skeletal dysplasias.
- Understanding these genetic underpinnings can aid in diagnosis, genetic counseling, and potential therapeutic strategies for MED patients.