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Autosomal recessive brachyolmia
Brachyolmia, recessive type is a form of brachyolmia (see this term), a group of rare genetic skeletal disorders, characterized by short-trunked short stature with platyspondyly and scoliosis. Corneal opacities and precocious calcification of the costal cartilage are rare syndromic components. Premature pubarche may occur.
ORPHA:448242Classification level: Disorder
The precise prevalence of this form of brachyolmia is not known. About 20 cases have been reported. Cases have been reported in various ethnic groups (Japan, Korea, Turkey), sometimes related to consanguineous unions. However, a majority of cases reported so far were of Turkish origin.
Patients with Brachyolmia, recessive type generally have a normal birth weight and length. Platyspondyly is present in early childhood but patients usually come to medical attention in late childhood or early puberty as a result of stunted growth and short trunk. The radiographic features include platyspondyly with rectangular vertebral bodies and irregular end plates, broad ilia, short femoral neck, and broad proximal interphalangeal joints. Longitudinal striations in the femoral neck are occasionally seen. Precocious calcifications of the costal cartilage are described. The condition is described as relatively benign with the exception of mild non-specific backache and mild scoliosis beginning in young adulthood. However, reports are limited about the final outcome of musculoskeletal morbidity. Mental status and facies are reported to be normal. Some patients are reported to have peripheral punctuate opacities in the cornea found on slit lamp examination (formerly Toledo type).
A number of different mutations in the PAPSS2 gene (10q23.2-q23.3) have been reported in affected patients. PAPPS2 encodes PAPS (3'-phosphoadenosine 5'-phosphosulfate) synthase 2. PAPSS2 mutations were also reported to cause two other disorders: spondyloepimetaphyseal dysplasia, PAPSS2 type (see this term), and spondylodysplasia and premature pubarche before the discovery of the molecular basis of brachyolmia, recessive type (Hobaek/Toledo type).
Genetic counseling should be provided to affected families based on the observed autosomal recessive pattern of inheritance.