Spondyloepimetaphyseal dysplasia (SEMD), X-linked, with mental deterioration is a very rare condition that begins in infancy or early childhood. Infants are normal at birth. During development, SEMD, X-linked, with mental deterioration causes a person to be shorter than most other people and have growth problems. Someone with this condition will also have decreased intellectual ability which worsens as the person gets older.
SEMD, X-linked, with mental deterioration will cause someone to have bone growth problems in the femur (thigh bone) and the spine (the group of bones that run down a person’s back). Someone with this condition will have short fingers and toes. It also causes the brain to have growth and development problems.
SEMD, X-linked, with mental deterioration is passed down from parents to their children through genes. Genes are segments of DNA that act as the body’s instruction manual. DNA is wound up tightly into structures called chromosomes. Males get an X chromosome from their mom and a Y chromosome from their dad. Females have two X chromosomes, one from each parent. SEMD, X-linked, with mental deterioration is inherited in an X-linked recessive pattern. This means that a female needs both of her X chromosomes to have a changed (mutated) gene in order to have SEMD. Females who have one X chromosome with the changed gene will not have the disease, but these females can pass the changed gene down to their children. Because males only have one X chromosome, they will have SEMD, X-linked, with mental deterioration if their X chromosome has the changed gene.
If you or a family member has been diagnosed with SEMD, X-linked, with mental deterioration, talk to your doctor about the most current treatment options. Support groups are also good sources of support and information.