User:Herrmane/sandbox

Mutations in the RNA component of RNase MRP cause cartilage-hair hypoplasia(CHH), a pleiotropic human disease. Two categories of mutations involving RNAse MRP have been identified in patients with CHH. The first type is when an insertion, duplication, or triplication occurs at the promoter of the RNAse MRP gene between the TATA box and the transcription initiation site. This causes the the initiation of RNAse MRP to be slow, or to not occur at all. The second category consists of mutations that are in the transcribed RNA made by the RNAse MRP. Patients with CHH have been identified to have over 70 different mutations in the RNA transcript made by RNAse MRP, whereas around 30 distinct mutations have been identified in the promoter region of the RNAse MRP gene. Most CHH patients have a combination of either a promoter mutation in one allele along with a RNAse MRP RNA mutation in the other allele, or a combination of two RNAse MRP RNA mutations in both alleles. The fact that there is not often a mutation in the promoter region in both alleles shows the lethality of not having this RNA present that is transcribed by RNAse MRP.