Question: How many people are affected by cartilage-hair hypoplasia ?
Answer: Cartilage-hair hypoplasia occurs most often in the Old Order Amish population, where it affects about 1 in 1,300 newborns. In people of Finnish descent, its incidence is approximately 1 in 20,000. Outside of these populations, the condition is rare, and its specific incidence is not known. It has been reported in individuals of European and Japanese descent.
Source: GHR

Question: What are the genetic changes related to cartilage-hair hypoplasia ?
Answer: Cartilage-hair hypoplasia is caused by mutations in the RMRP gene. Unlike many genes, the RMRP gene does not contain instructions for making a protein. Instead, a molecule called a noncoding RNA, a chemical cousin of DNA, is produced from the RMRP gene. This RNA attaches (binds) to several proteins, forming an enzyme complex called mitochondrial RNA-processing endoribonuclease, or RNase MRP. The RNase MRP enzyme is thought to be involved in several important processes in the cell. For example, it likely helps copy (replicate) the DNA found in the energy-producing centers of cells (mitochondria). The RNase MRP enzyme probably also processes ribosomal RNA, which is required for assembling protein building blocks (amino acids) into functioning proteins. In addition, this enzyme helps control the cell cycle, which is the cell's way of replicating itself in an organized, step-by-step fashion. Mutations in the RMRP gene likely result in the production of a noncoding RNA that is unstable. This unstable molecule cannot bind to some of the proteins needed to make the RNase MRP enzyme complex. These changes are believed to affect the activity of the enzyme, which interferes with its important functions within cells. Disruption of the RNase MRP enzyme complex causes the signs and symptoms of cartilage-hair hypoplasia.
Source: GHR

Question: Is cartilage-hair hypoplasia inherited ?
Answer: This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
Source: GHR

Question: What are the treatments for cartilage-hair hypoplasia ?
Answer: These resources address the diagnosis or management of cartilage-hair hypoplasia: - Gene Review: Gene Review: Cartilage-Hair Hypoplasia - Anauxetic Dysplasia Spectrum Disorders - Genetic Testing Registry: Metaphyseal chondrodysplasia, McKusick type These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
Source: GHR