Schimke immuno-osseous dysplasia is a condition characterized by short stature, kidney disease, and a weakened immune system. People with this condition have flattened spinal bones (vertebrae) that shorten their neck and trunk. The adult height for people with this condition is typically between 3 and 5 feet. Additional skeletal problems in people with Schimke immuno-osseous dysplasia include abnormalities of the hip joints and the end of the leg bones where they meet the hip joint. These skeletal problems can cause the hip joints to break down (degenerate) over time, leading to joint pain and a limited range of movement. This combination of skeletal problems and spinal abnormalities is called spondyloepiphyseal dysplasia as it affects the bones of the spine (spondylo-) and the ends of long bones (epiphyses) in the legs. It affects most people with Schimke immuno-osseous dysplasia. People with Schimke immuno-osseous dysplasia often have kidney (renal) disease that may lead to life-threatening renal failure and end-stage renal disease (ESRD).

Variants (also called mutations) in the SMARCAL1 gene can cause Schimke immuno-osseous dysplasia. The SMARCAL1 gene provides instructions for producing a protein that interacts with DNA. The SMARCAL1 protein helps when the process of making new copies of DNA, called DNA replication, is blocked by DNA damage. When DNA replication stalls, the SMARCAL1 proteins repair DNA damage by reattaching the two strands of DNA's double helix and allowing replication to proceed. Research on the function of similar proteins suggests that SMARCAL1 can influence the activity (expression) of other genes.

Schimke immuno-osseous dysplasia is a very rare condition.  The prevalence is estimated to be 1 in 1 million to 3 million people.

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell must have a variant to cause the disorder. The parents of an individual with an autosomal recessive condition each carry one copy of the altered gene, but they typically do not show signs and symptoms of the condition.

Published Date: July 08, 2024
Published By: National Institutes of Health