For more on getting a definitive genetic diagnosis, see The Genie's Out of the Bottle: Genetic testing in the 21st century. Reliability and specificity of genetic tests are improving, and the number of tests available is expanding rapidly as knowledge and technology improve. However, it has implications for the whole family that must be considered (see Causes/Inheritance). Genetic testing requires only a blood sample. 1,2,3Ī doctor probably will recommend genetic testing if SMA is suspected because this is the least invasive and most accurate way to diagnose chromosome 5-related SMA (types 1-4).
As a result, SMA types 2 and 3 might be confused with other neuromuscular disease, such as Duchenne muscular dystrophy. Usually, CK levels are normal in patients diagnosed with SMA type 1 but can be a slightly elevated in patients diagnosed with other types of SMA, such as types 2 and 3. High blood CK levels aren’t harmful in and of themselves, but they do indicate that muscle damage has occurred. This is a nonspecific test because CK levels are elevated in many neuromuscular diseases, but it’s often a useful test. Other signs can help to confirm the diagnosis, such as a history of motor difficulties, loss of motor skills, proximal muscle weakness, hyporeflexia (absence of reflexes), tongue fasciculations (involuntary twitches), and signs for low motor neuron disease.Ī doctor may order a blood test for an enzyme called creatine kinase (CK), which leaks out of muscles that are deteriorating. Muscle weakness and hypotonia should be the first signs that raise suspicion for SMA in babies. The first steps in diagnosis of a neuromuscular disease are usually an in-office physical examination and family history, with some simple tests to distinguish spinal muscular atrophy (SMA) from similar conditions (such as muscular dystrophy).
0 kommentar(er)
