Spondyloepimetaphyseal Dysplasia with Joint Laxity, Type 1 (SEMDJL1) is a rare autosomal recessive skeletal dysplasia characterized by dwarfism, articular hypermobility, and progressive intractable spinal malalignment. Affected children are born with a typical facies which includes a characteristic oval shape, a long upper lip, protruberant eyes, and sometimes, mild sclera blueness. About a third of the patients have a cleft palate, while a similar proportion also has structural cardiac defects, like VSD, ASD, and myocardial infarction. Other abnormalities like mental retardation, myopia, Hirschsprung's disease, and unilateral megaureter may also be seen in some patients. Radiologically, severe and progressive kyphoscoliosis and platyspondyly is seen. The vertebral bodies are biconvex with irregular endplates. Epiphyseal ossification is delayed in the long bones, and the metaphyses are wide and irregular, with a coarse trabecular pattern. Iliac wings are flared, sacro-sciatic notches are short, distal radius and ulna are expanded, tubular limb bones are short, and traction exostoses may be present. Coxa valga with hip dislocation is also seen.
Differential diagnoses of the condition include conditions such as diastrophic dysplasia, Larsen syndrome, mucopolysaccharidoses, and other spondyloepimetaphyseal dysplasias. The malalignment of the spine in this condition, complicated by laxity of the ligaments, is usually very difficult to treat, and requires some kind of internal fixation as opposed to just external bracing. In spite of it, the condition may continue to progress to spinal cord compression and paraplegia. Prognosis is usually not good, with most patients succumbing to complications of spinal cord suppression and/or cardiorespiratory compromise before reaching adulthood. The vast majority of patients have been identified in the Afrikaans speaking population of South Africa.
[See: Syria > Farag et al., 1987].
Farag et al. (1987) described a family of Syrian origin affected by a form of spondyloepimetaphyseal dysplasia. The proband presented with disproportionate short stature, with height and weight below the 3rd centile, marked rhizomelic shortening in all four limbs, and a dish-like facies with frontal bossing, hypertelorism, depressed nasal bridge, anteverted nostrils, long philtrum, and a narrow external auditory meatus. He was also found to suffer from bilateral moderate mixed hearing loss, cleft palate, and camptodactyly. The propositus had two younger siblings of either sex, with a similar presentation in infancy. The younger of these two had, in addition, micrognathia and glossoptosis. Both had recurrent functions and died within the first year of life. Radiological findings in all three siblings included lordosis of the spine in the cervicothoracic region, mild generalized platyspondyly, and shortening of all long bones with striking enlargement of the metaphyses and loss of bone molding. The parents and four other siblings were normal. Parental consanguinity was not reported. Farag et al. (1987) found it difficult to make a firm diagnosis, but concluded that the disorder was either Kniest disease with autosomal recessive inheritance, or a new spondyloepimetaphyseal dysplasia.