Cerebellar infarction due to atlantoaxial subluxation in spondyloepimetaphyseal dysplasia-joint laxity type 1 case.

Introduction: Spondyloepimetaphyseal dysplasia with joint laxity type 1 (SEMD-JL1) is an extremely rare skeletal dysplasia belonging to a group of disorders called linkeropathies. It is characterized by skeletal and connective tissue abnormalities. Biallelic variants in genes encoding enzymes that synthesize the tetrasaccharide linker region of glycosaminoglycans lead to linkeropathies, which exhibit clinical and phenotypic features that overlap with each other. SEMD-JL1 results in impaired growth and short stature, along with increased joint flexibility leading to limb joint dislocations and progressive spinal deformity.

Methods and result: Whole exome sequencing was performed on the patient's genomic DNA. A novel variant in the B3GALT6 gene was detected as homozygous. During the patient's follow-up, signs of cerebellar infarction was observed due to atlantoaxial subluxation. Posterior circulation ischemic strokes have not been described with SEMD-JL1 and it was the second case in the skeletal dysplasia group to develop posterior circulation ischemic stroke due to atlantoaxial luxation.

Conclusion: Linkeropathies present with varying clinical manifestations and necessitate comprehensive genetic testing for accurate diagnosis of this complex patient group. Skeletal dysplasias, such as spondyloepimetaphyseal dysplasia, may be accompanied by atlantoaxial instability that can lead to serious spinal symptoms and even sudden death.