SEMD with joint laxity type

Spondyloepimetaphyseal dysplasia with joint laxity type (SEMD-JL) is an autosomal recessive skeletal dysplasia that consists of type 1 (SEMDJL1, SEMD-JL Beighton type) and type 2 (SEMDJL2, SEMD-leptodactylic or Hall type). SEMDJL1 is caused by mutation in the B3GALT6 gene. The individuals with SEMDJL1 show the characteristic vertebral abnormalities, ligamentous laxity that result in spinal misalignment and progressive severe kyphoscoliosis, thoracic asymmetry, and respiratory compromise resulting in early death. The individuals with SEMDJL2 was identified mutations in KIF22 as the cause of this disease. Its characteristic manifestation includes short stature, midface hypoplasia, generalized ligamentous laxity causing mild kyphoscoliosis and progressive genu valgum.