Spondyloepimetaphyseal dysplasia, short limb-abnormal calcifications type: Progressive radiological findings from fetal age to adolescence

Background: Spondyloepimetaphyseal dysplasia, short limb-abnormal calcifications type (SEMD, SL-AC) is a rare autosomal recessive condition with a grave prognosis. Objective: We aimed to describe the progression of symptoms from fetal age to adolescence in SMED, SL-AC patients. Materials and methods: We retrospectively evaluated radiological findings on plain films, CT and MRI for eight children with genetically proven SEMD (male:female ratio 4:4, ages 30-week fetus to 18 years) and summarized findings from case reports and case series in the literature. Results: Early and persistent radiological signs of SEMD were platyspondyly, chest narrowing, short ribs, and broad and short bones in the extremities and pelvis. In five children, we observed an unusually massive C2 vertebral body with narrowing of the spinal canal. Disease progression was characterized by anterior dislocation of C1, kyphoscoliosis, bowing of the limbs, metaphyseal and epiphyseal changes and abnormal calcifications. Earliest appearance of abnormal calcifications was 1.5 years; four children had no abnormal calcifications at diagnosis. There were persistent large open fontanelles in all children with skull radiographs, including a 17-year-old boy. Disease severity and progression were variable. Complications included cord compression and restrictive lung changes. Conclusion: Disease severity and progression vary. Absence of abnormal calcifications does not preclude the diagnosis. An unusual, massive C2 vertebral body may contribute to spinal cord compression. Persistent open fontanelles should be added to the clinical characteristics of SEMD, SL-AC.