Prevalence
Prevalence is unknown, but about 40 patients have been described in the literature as of 2022.
Clinical Characteristics
Individuals with pathogenic variants in B4GALT7 have a condition defined as spondylodysplastic Ehlers-Danlos Syndrome type 1 (EDSSPD1 B4GALT7-related). It is characterized by short stature, muscle hypotonia, bowing of limbs, joint hypermobility (especially of the hands), skin hyperextensibility, and soft, doughy skin. Other key features, not always present in affected individuals, include radioulnar synostosis, osteopenia, developmental delay, pes planus, and ocular abnormalities.
Molecular Characteristics
B4GALT7 variants responsible for the EDSSPD1 B4GALT7-related phenotype are mostly hypomorphic missense variants, following an autosomal recessive mode of inheritance.
Genetic Counselling
Since inheritance of this condition is autosomal recessive, couples with an affected child or couples of carriers have a 25% risk of having another affected child at each pregnancy.
Management
Management requires a multi-disciplinary approach based on the patient's clinical manifestations. Musculoskeletal anomalies may require a precocious orthopedic intervention and subsequent rehabilitation.
B4GALT7