A Family Guide to Non-Oncologic Blood Disorders
Cartilage-Hair Hypoplasia
What is cartilage-hair hypoplasia? Cartilage-hair hypoplasia (CHH) is an autosomal recessive disorder, meaning that each parent carries one copy of the defective gene and passes it along to their child. CHH causes short-limbed dwarfism (short stature), other associated bone abnormalities, fine sparse hair, and an abnormal immune system. The following are the most common symptoms of CHH. How- ever each child may experience symptoms differently. Symp- toms may include: • Short stature • Short fingers and toes • Bowed legs • Loose joints, especially in the hands and feet • Difficultly extending elbows • Blonde, sparse, and fine hair • Increased risk of infections, especially varicella, the virus that causes chicken pox • Severe combined immunodeficiency • Anemia (too few red blood cells) • Increased risk of cancers » » Leukemia » » Lymphomas » » Tumors of the skin, eye, and liver • Intestinal issues, including Hirschsprung disease, a disorder causing severe constipation and intestinal blockage, and celiac disease, the inability to absorb gluten from wheat or other grains • Decreased sperm count in male patients How is CHH diagnosed? Prenatal screening can be considered if there is a family history. CHH typically is diagnosed in infancy through the following steps: • Complete physical exam • Complete family history • X-rays • Blood test
What test or procedures will my child need? • Complete blood count • Immune function testing (T cell and B cell function studies) • Genetic testing to look for a mutation in the ribonucle- ase mitochondrial RNA-processing (RMRP) gene • Immunoglobulin (antibodies) level testing (IgG, IgA, and IgM) • Bone X-rays • Your child should be seen by an immunologist (immune system) and an orthopedic (bone) doctor. What are the treatment options for CHH? • Aggressive treatment of all infections. More than 50% of children with CHH have a compromised immune sys- tem and inability to protect themselves from infections. • Avoid live vaccines, including the varicella vaccination. • Prophylactic antibiotics to prevent lung infections • Surgery may be needed for severe bowing of the legs. • Your medical team will determine the best treatment plan for your child. How successful is the treatment? The life expectancy for children with CHH varies. Some chil- dren that have decreased immune systems can develop poten- tially life-threatening infections and varicella can be especially dangerous. An antiviral medication (Acyclovir) may be used to treat this infection. Growth hormone has had limited success in increasing height, and CHH patients are at greater risk of developing cancers throughout their lifetime. Stem Cell Transplant Indications Stem cell transplant is the only curative treatment for the immune system problems associated with CHH. However, stem cell transplant will not fix the other skeletal and intestinal issues that patients with CHH can experience.
Cartilage-Hair Hypoplasia
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