Congenital muscular dystrophy type 1A
- Merosin-negative congenital muscular dystrophy
- Merosin-deficient congenital muscular dystrophy
- Muscular dystrophy, congenital, merosin-deficient
- Laminin alpha-2 deficiency
Although most individuals affected with MDC1A have complete deficiency of the merosin protein, a few individuals have only a partial deficiency. Among individuals with a partial deficiency, the severity and age of onset varies greatly. One study reported that approximately 12% of individuals have later onset, slowly progressive weakness.
The Human Phenotype Ontology provides the following list of signs and symptoms for Congenital muscular dystrophy type 1A. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms.
The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature.
The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined.
Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
- Congenital Muscular Dystrophy. NORD. January 6, 2010; http://www.rarediseases.org/rare-disease-information/rare-diseases/byID/1196/viewAbstract. Accessed 9/26/2011.
- Susan Sparks et al. Congenital Muscular Dystrophy Overview. GeneReviews. January 4, 2011; http://www.ncbi.nlm.nih.gov/books/NBK1291/. Accessed 9/26/2011.
- M. Fardeau. Congenital muscular dystrophy type 1A. Orphanet. April 2009; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=258. Accessed 9/26/2011.
- K. Jones et al. The expanding phenotype of laminin a2 chain (merosin) abnormalities: case series and review. J Med Genet. October 2001; 38(10):649-657.