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Diseases

Genetic and Rare Diseases Information Center (GARD)

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Spinal muscular atrophy type 2


Other Names for this Disease

  • Muscular atrophy, spinal, infantile chronic form
  • Muscular atrophy, spinal, intermediate type
  • SMA II
  • SMA2
  • Spinal muscular atrophy type II
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Symptoms

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What are the signs and symptoms of spinal muscular atrophy type 2?

The signs and symptoms of spinal muscular atrophy type 2 (SMA II) typically become apparent between 6 and 12 months of age, although poor muscle tone may be noticed at birth or within the first few months of life. Affected individuals may slowly gain some motor milestones, but usually do not have motor milestones beyond the ability to sit independently when placed in a sitting position. Finger trembling and general poor muscle tone are almost always present. Affected individuals generally lose the ability to sit independently by their mid-teens, on average. The life expectancy of affected individuals is not exactly known; some individuals may live into adolescence, while others may live to the third or fourth decade of life.[1] For information about the signs and symptoms of spinal muscular atrophy in general, click here.
Last updated: 11/28/2011

The Human Phenotype Ontology provides the following list of signs and symptoms for Spinal muscular atrophy type 2. 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.

Signs and Symptoms Approximate number of patients (when available)
Amyotrophy -
Autosomal recessive inheritance -
Degeneration of anterior horn cells -
EMG abnormality -
Hand tremor -
Muscle weakness -
Recurrent respiratory infections -
Tongue fasciculations -

Last updated: 11/3/2014

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.


References
  1. Thomas W Prior, Barry S Russman. Spinal Muscular Atrophy. GeneReviews. January 27, 2011; http://www.ncbi.nlm.nih.gov/books/NBK1352/. Accessed 11/28/2011.


Other Names for this Disease
  • Muscular atrophy, spinal, infantile chronic form
  • Muscular atrophy, spinal, intermediate type
  • SMA II
  • SMA2
  • Spinal muscular atrophy type II
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.