301-519-2100 • FAX 301-519-2892 • 207 PERRY PARKWAY GAITHERSBURG, MD 20877
SEARCH
Cartilage Hair Hypoplasia
Metaphyseal Dysplasia without Hypotrichosis
Spondylometaepiphyseal Dysplasia, Menger type
Anauxetic Dysplasia
RMRP
Cartilage-hair hypoplasia (CHH) is characterized by short-limbed dwarfism with cone-shaped epiphyses and metaphyseal flaring, sparse, light-colored and thin hair (hypotrichosis), as well as immunological and hematological anomalies, such as susceptibility to chickenpox, neutropenia and anemia. Some patients may also have Hirschsprung disease, impaired spermatogenesis, and increased susceptibility to cancer. Other skeletal abnormalities may include incomplete extension at the elbows, chest deformities, lumbar lordosis, joint laxity, bowed legs, genu varum, and excessively long fibula distally relative to the tibia. Hypoplasia of the cartilage is seen microscopically. Metaphyseal dysplasia without hypotrichosis was initially described as a distinct entity from CHH with identical skeletal features, and lacking hypotrichosis and immunodeficiency. Anauxetic dysplasia is a form of extreme short stature of prenatal onset, hypodontia, and mild mental retardation. Recent data shows that these three disorders are allelic as each condition is caused by mutations in the untranscribed RNase MRP (RMRP) gene, which codes for an RNA subunit of an RNA processing enzyme complex.
Mutations in the RMRP gene are identified by sequence analysis of the coding region and portions of the promoter region. The analysis is done on genomic DNA obtained from buccal swabs or blood (1-5cc in EDTA). In published studies, an RMRP mutation was identified in 94% of patients with the clinical diagnosis of Cartilage Hair Hypoplasia. The sensitivity of the test for patients with the diagnosis of Metaphyseal Dysplasia without Hypotrichosis is unknown. Mutations in RMRP have also been identified in patients with Anauxetic Dysplasia (spondylometaepiphyseal dysplasia Menger type).
Information Sheet, including prices and CPT codes
Consent Document
Genetic Test Sample Submission Form (Test Requisition Form) including Payment Options
Dwarfism, short-limbed, short-limbed dwarfism, cone-shaped epiphyses, Neutropenia, anemia, anauxetic, Menger, spondylo, short stature
© 2000 - 2008 GeneDx, Inc. All rights reserved.
