Spondyloepimetaphyseal dysplasia, Genevieve type (SEMDG) is a very rare disease that causes growth and development problems. A person with SEMDG will have a severe developmental delay. This means they will not develop and learn the same way that most people their age can. SEMDG will also cause someone to be shorter than most other people.
SEMDG causes bone growth problems in the femurs and carpals. The femurs and carpals are bones in the body. The femur is the large bone in the thigh. The carpals are the bones that make up the wrists.
SEMDG is passed down from parents to their children through genes. Genes act as an instruction manual for the body. Genes are made up of DNA. DNA is a “code” made up of small parts called nucleotides. A gene mutation is when one or more nucleotides in the DNA “code” that makes up a gene is changed. SEMDG is caused by a mutation in the NANS gene. SEMDG is inherited in an autosomal recessive pattern. This means that both parents pass a mutation in the NANS gene down to the child in order for the child to have SEMDG.
If you or a family member has been diagnosed with SEMDG, talk to your doctor about the most current treatment options. Support groups are also good sources of support and information.