In Cartilage-Hair Hypoplasia, the RMRP gene is affected.
2. On which chromosome is the gene located? Find an image of the chromosome or a human karyotype and identify the location of the gene.
The RMRP gene is located on Chromosome 9, as show in the image below where the yellow arrow indicates the location of RMRP.
The function of the "normal" gene is to produce noncoding RNA, which in turn binds to proteins and forms Mitochondrial RNA-processing endoribonuclease, or RNase MRP. This enzyme helps DNA in the motochondria replicate and processes ribosomal RNA, which helps turn amino acids into proteins in the translation process
The symptoms of Cartilage-Hair Hypoplasia are: immune deficiency, fine/sparse hair, and short stature along with other skeletal abnormalities, light-colored hair and light-colored skin. This is related to the function of the protein because when the RNA is unstable, it cannot bind to proteins and its control in the cell cycle and functions within a cell are disrupted, leading to the symptoms associated with cartilage-hair hypoplasia.
People with cartilage-hair hypoplasia have a guanine substituted for the adenine at position 70 in the RMRP gene.
The non-"normal" form of the gene is still able to produce noncoding RNA, but this RNA is altered just enough to make it unable to bind to different proteins and disrupts the RNase MRP complex in the cells.
This disease is inherited in an autosomal recessive pattern.
Cartilage-Hair Hypoplasia is most frequent among the Old Order Amish population and affects about 1 in 1,300 babies. Among people of Finnish descended people, it is about 1 in 20,000 people.
Currently, supportive forms of treatment are available in which antibiotics can be given to fight infections people with this disease can be more susceptible to as a result of their suppressed immune system.
A form of treatment depends on whether the affected person has T-cell immunoeficiency or not. If they do, this can be treated with a bone marrow transplant. Antibiotics can be given out to fight the infections and diseases they are more susceptible to getting such as chickenpox.
http://www.lpaonline.org/mc/page.do?sitePageId=37298&orgId=lpa Little People of America is a web-based organization for people suffering from diseases that cause short stature and dwarfism, from CHH to Achondroplasia. It provides information about the various diseases, links to other support and research organizations, and information about adoption, scholarships, and medical support.