Submitted Successfully!
To reward your contribution, here is a gift for you: A free trial for our video production service.
Thank you for your contribution! You can also upload a video entry or images related to this topic.
Version Summary Created by Modification Content Size Created at Operation
1
Catherine Yang
 + 746 word(s) 746 2020-12-15 07:19:02

Video Upload Options

Do you have a full video?
Send video materials Upload full video

Confirm

Are you sure to Delete?
Yes No
Cite
If you have any further questions, please contact Encyclopedia Editorial Office.
Yang, C. Cartilage-Hair Hypoplasia. Encyclopedia. Available online: https://encyclopedia.pub/entry/5193 (accessed on 20 April 2024).
Yang C. Cartilage-Hair Hypoplasia. Encyclopedia. Available at: https://encyclopedia.pub/entry/5193. Accessed April 20, 2024.
Yang, Catherine. "Cartilage-Hair Hypoplasia" Encyclopedia, https://encyclopedia.pub/entry/5193 (accessed April 20, 2024).
Yang, C. (2020, December 24). Cartilage-Hair Hypoplasia. In Encyclopedia. https://encyclopedia.pub/entry/5193
Yang, Catherine. "Cartilage-Hair Hypoplasia." Encyclopedia. Web. 24 December, 2020.
Cartilage-Hair Hypoplasia
Edit
This entry is adapted from the peer-reviewed paper https://medlineplus.gov/genetics/condition/cartilage-hair-hypoplasia

Cartilage-hair hypoplasia is a disorder of bone growth characterized by short stature (dwarfism) with other skeletal abnormalities; fine, sparse hair (hypotrichosis); and abnormal immune system function (immune deficiency) that can lead to recurrent infections.

genetic conditions

1. Introduction

People with cartilage-hair hypoplasia have unusually short limbs and short stature from birth. They typically have malformations in the cartilage near the ends of the long bones in the arms and legs (metaphyseal chondrodysplasia), which then affects development of the bone itself. Most people with cartilage-hair hypoplasia are unusually flexible in some joints, but they may have difficulty extending their elbows fully.

Affected individuals have hair that is lighter in color than that of other family members because the core of each hair, which contains some of the pigment that contributes the hair's color, is missing. The missing core also makes each strand of hair thinner, causing the hair to have a sparse appearance overall. Unusually light-colored skin (hypopigmentation), malformed nails, and dental abnormalities may also be seen in this disorder.

The extent of the immune deficiency in cartilage-hair hypoplasia varies from mild to severe. Affected individuals with the most severe immune problems are considered to have severe combined immunodeficiency (SCID). People with SCID lack virtually all immune protection from bacteria, viruses, and fungi and are prone to repeated and persistent infections that can be very serious or life-threatening. These infections are often caused by "opportunistic" organisms that ordinarily do not cause illness in people with a normal immune system. Most people with cartilage-hair hypoplasia, even those who have milder immune deficiency, experience infections of the respiratory system, ears, and sinuses. In particular, the chicken pox virus (varicella) often causes dangerous infections in people with this disorder. Autoimmune disorders, which occur when the immune system malfunctions and attacks the body's tissues and organs, occur in some people with cartilage-hair hypoplasia. Affected individuals are also at an increased risk of developing cancer, particularly certain skin cancers (basal cell carcinomas), cancer of blood-forming cells (leukemia), and cancer of immune system cells (lymphoma).

Some people with cartilage-hair hypoplasia experience gastrointestinal problems. These problems may include an inability to properly absorb nutrients or intolerance of a protein called gluten found in wheat and other grains (celiac disease). Affected individuals may have Hirschsprung disease, an intestinal disorder that causes severe constipation, intestinal blockage, and enlargement of the colon. Narrowing of the anus (anal stenosis) or blockage of the esophagus (esophageal atresia) may also occur.

2. Frequency

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.

3. Causes

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.

3.1. The Gene Associated with Cartilage-Hair Hypoplasia

  • RMRP

4. Inheritance

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.

5. Other Names for This Condition

  • cartilage-hair syndrome
  • CHH
  • McKusick's metaphyseal chondrodysplasia syndrome
  • metaphyseal chondrodysplasia, McKusick type
  • metaphyseal chondrodysplasia, recessive type

References

  1. Ganapathi KA, Shimamura A. Ribosomal dysfunction and inherited marrow failure.Br J Haematol. 2008 May;141(3):376-87. doi: 10.1111/j.1365-2141.2008.07095.x.Review.
  2. Kwan A, Manning MA, Zollars LK, Hoyme HE. Marked variability in theradiographic features of cartilage-hair hypoplasia: case report and review of theliterature. Am J Med Genet A. 2012 Nov;158A(11):2911-6. doi:10.1002/ajmg.a.35604.
  3. Martin AN, Li Y. RNase MRP RNA and human genetic diseases. Cell Res. 2007Mar;17(3):219-26. Review.
  4. Matesic D, Hagan JB. Cartilage-hair hypoplasia. Mayo Clin Proc. 2007Jun;82(6):655.
  5. Mattijssen S, Welting TJ, Pruijn GJ. RNase MRP and disease. Wiley Interdiscip Rev RNA. 2010 Jul-Aug;1(1):102-16. doi: 10.1002/wrna.9.
  6. Nakashima E, Tran JR, Welting TJ, Pruijn GJ, Hirose Y, Nishimura G, Ohashi H, Schurman SH, Cheng J, Candotti F, Nagaraja R, Ikegawa S, Schlessinger D.Cartilage hair hypoplasia mutations that lead to RMRP promoter inefficiency orRNA transcript instability. Am J Med Genet A. 2007 Nov 15;143A(22):2675-81.
  7. Notarangelo LD, Roifman CM, Giliani S. Cartilage-hair hypoplasia: molecularbasis and heterogeneity of the immunological phenotype. Curr Opin Allergy ClinImmunol. 2008 Dec;8(6):534-9. doi: 10.1097/ACI.0b013e328310fe7d. Review.
  8. Thiel CT, Mortier G, Kaitila I, Reis A, Rauch A. Type and level of RMRPfunctional impairment predicts phenotype in the cartilage hairhypoplasia-anauxetic dysplasia spectrum. Am J Hum Genet. 2007 Sep;81(3):519-29.
  9. Thiel CT, Rauch A. The molecular basis of the cartilage-hairhypoplasia-anauxetic dysplasia spectrum. Best Pract Res Clin Endocrinol Metab.2011 Feb;25(1):131-42. doi: 10.1016/j.beem.2010.08.004. Review.
  10. Welting TJ, Mattijssen S, Peters FM, van Doorn NL, Dekkers L, van Venrooij WJ,Heus HA, Bonafé L, Pruijn GJ. Cartilage-hair hypoplasia-associated mutations inthe RNase MRP P3 domain affect RNA folding and ribonucleoprotein assembly.Biochim Biophys Acta. 2008 Mar;1783(3):455-66. doi: 10.1016/j.bbamcr.2007.11.016.
More
©Text is available under the terms and conditions of the Creative Commons-Attribution ShareAlike (CC BY-SA) license; additional terms may apply. By using this site, you agree to the Terms and Conditions and Privacy Policy.
Upload a video for this entry
Information
Subjects: Genetics & Heredity
Contributor MDPI registered users' name will be linked to their SciProfiles pages. To register with us, please refer to https://encyclopedia.pub/register :
Catherine Yang
View Times: 362
Entry Collection: MedlinePlus
Revision: 1 time (View History)
Update Date: 24 Dec 2020
Table of Contents
    1000/1000
    Hot Most Recent
    Feedback