Those at risk of being carriers of "SMN1" deletion, and thus at risk of having offspring affected by SMA, can undergo carrier analysis using a blood or saliva sample. The American College of Obstetricians and Gynecologists recommends all people thinking of becoming pregnant be tested to see if they are a carrier.

Routine prenatal or neonatal screening for SMA is controversial, because of the cost, and because of the severity of the disease. Some researchers have concluded that population screening for SMA is not cost-effective, at a cost of $5 million per case averted in the United States as of 2009. Others conclude that SMA meets the criteria for screening programs and relevant testing should be offered to all couples. The major argument for neonatal screening is that in SMA type I, there is a critical time period in which to initiate therapies to reduce loss of muscle function and proactive treatment in regards to nutrition.

Electrophysiological evidence of denervation with intact motor and sensory nerve conduction findings must be made by using nerve conduction studies, usually in conjunction with EMG. The presence of polyphasic potentials and fibrillation at rest are characteristic of congenital dSMA.

The following are useful in diagnosis:

- Nerve conduction studies (NCS), to test for denervation

- Electromyography (EMG), also to detect denervation

- X-ray, to look for bone abnormalities

- Magnetic resonance imaging (MRI)

- Skeletal muscle biopsy examination

- Serum creatine kinase (CK) level in blood, usually elevated in affected individuals

- Pulmonary function test

The diagnosis for DMSA1 is usually masked by a diagnosis for a respiratory disorder. In infants, DMSAI is usually the cause of acute respiratory insufficiency in the first 6 months of life. The respiratory distress should be confirmed as diaphragmatic palsy by fluoroscopy or by electromyography. Although the patient may have a variety of other symptoms the diaphragmatic palsy confirmed by fluoroscopy or other means is the main criteria for diagnosis. This is usually confirmed with genetic testing looking for mutations in the "IGHMBP2" gene.

The patient can be misdiagnosed if the respiratory distress is mistaken for a severe respiratory infection or DMSA1 can be mistaken for SMA1 because their symptoms are so similar but the genes which are affected are different. This is why genetic testing is necessary to confirm the diagnosis of DMSA.

Electrodiagnostic testing (also called electrophysiologic) includes nerve conduction studies which involves stimulating a peripheral motor or sensory nerve and recording the response, and needle electromyography, where a thin needle or pin-like electrode is inserted into the muscle tissue to look for abnormal electrical activity.

Electrodiagnostic testing can help distinguish myopathies from neuropathies, which can help determine the course of further work-up. Most of the electrodiagnostic abnormalities seen in myopathies are also seen in neuropathies (nerve disorders). Electrodiagnostic abnormalities common to myopathies and neuropathies include; abnormal spontaneous activity (e.g., fibrillations, positive sharp waves, etc.) on needle EMG and, small amplitudes of the motor responses compound muscle action potential, or CMAP during nerve conduction studies. Many neuropathies, however, cause abnormalities of sensory nerve studies, whereas myopathies involve only the muscle, with normal sensory nerves. The most important factor distinguishing a myopathy from a neuropathy on needle EMG is the careful analysis of the motor unit action potential (MUAP) size, shape, and recruitment pattern.

There is substantial overlap between the electrodiagnostic findings the various types of myopathy. Thus, electrodiagnostic testing can help distinguish neuropathy from myopathy, but is not effective at distinguishing which specific myopathy is present, here muscle biopsy and perhaps subsequent genetic testing are required.

In regards to the diagnosis of spinal and bulbar muscular atrophy, the "AR Xq12" gene is the focus. Many mutations are reported and identified as missense/nonsense, that can be identified with 99.9% accuracy. Test for this gene in the majority of affected patients yields the diagnosis.

On examination of muscle biopsy material, the nuclear material is located predominantly in the center of the muscle cells, and is described as having any "myotubular" or "centronuclear" appearance. In terms of describing the muscle biopsy itself, "myotubular" or "centronuclear” are almost synonymous, and both terms point to the similar cellular-appearance among MTM and CNM. Thus, pathologists and treating physicians use those terms almost interchangeably, although researchers and clinicians are increasingly distinguishing between those phrases.

In general, a clinical myopathy and a muscle biopsy showing a centronuclear (nucleus in the center of the muscle cell) appearance would indicate a centronuclear myopathy (CNM). The most commonly diagnosed CNM is myotubular myopathy (MTM). However, muscle biopsy analysis alone cannot reliably distinguish myotubular myopathy from other forms of centronuclear myopathies, and thus genetic testing is required.

Diagnostic workup is often coordinated by a treating neurologist. In the United States, care is often coordinated through clinics affiliated with the Muscular Dystrophy Association.

A 2006 study followed 223 patients for a number of years. Of these, 15 died, with a median age of 65 years. The authors tentatively concluded that this is in line with a previously reported estimate of a shortened life expectancy of 10-15 years (12 in their data).

Diagnostic procedures that may reveal muscular disorders include direct clinical observations. This usually starts with the observation of bulk, possible atrophy or loss of muscle tone. Neuromuscular disease can also be diagnosed by testing the levels of various chemicals and antigens in the blood, and using electrodiagnostic medicine tests including electromyography (measuring electrical activity in muscles) and nerve conduction studies.

In neuromuscular disease evaluation, it is important to perform musculoskeletal and neurologic examinations. Genetic testing is an important part of diagnosing inherited neuromuscular conditions.

Congenital dSMA has a relatively stable disease course, with disability mainly attributed to increased contractures rather than loss of muscle strength. Individuals frequently use crutches, knee, ankle, and/or foot orthoses, or wheelchairs. Orthopaedic surgery can be an option for some patients with severely impaired movement. Physical therapy and occupational therapy can help prevent further contractures from occurring, though they do not reverse the effects of preexisting ones. Some literature suggests the use of electrical stimulation or botulinum toxin to halt the progression of contractures.

Diagnosis requires a neurological examination and neuroimaging can be helpful.

BVVL can be differentially diagnosed from similar conditions like Fazio-Londe syndrome and amyotrophic lateral sclerosis, in that those two conditions don't involve sensorineural hearing loss, while BVVL, Madras motor neuron disease, Nathalie syndrome, and Boltshauser syndrome do. Nathalie syndrome does not involve lower cranial nerve symptoms, so it can be excluded if those are present. If there is evidence of lower motor neuron involvement, Boltshauser syndrome can be excluded. Finally, if there is a family history of the condition, then BVVL is more likely than MMND, as MMND tends to be sporadic.

Genetic testing is able to identify genetic mutations underying BVVL.

For the diagnosis of congenital muscular dystrophy, the following tests/exams are done:

- Lab study (CK levels)

- MRI (of muscle, and/or brain)

- EMG

- Genetic testing

The subtypes of congenital muscular dystrophy have been established through variations in multiple genes. It should be noted that phenotype, as well as, genotype classifications are used to establish the subtypes, in some literature.

One finds that congenital muscular dystrophies can be either autosomal dominant or autosomal recessive in terms of the inheritance pattern, though the latter is much more common

Individuals who suffer from congenital muscular dystrophy fall into one of the following "types":

DSMA1 is usually fatal in early childhood. The patient, normally a child, suffers a progressive degradation of the respiratory system until respiratory failure. There is no consensus on the life expectancy in DSMA1 despite a number of studies being conducted. A small number of patients survive past two years of age but they lack signs of diaphragmatic paralysis or their breathing is dependent on a ventilation system.

While the presence of several symptoms may point towards a particular genetic disorder of the spinal muscular atrophy group, the actual disease can be established with full certainty only by genetic testing which detects the underlying genetic mutation.

In terms of treatment for neuromuscular diseases (NMD), "exercise" might be a way of managing them, as NMD individuals would gain muscle strength. In a study aimed at results of exercise, in muscular dystrophy and Charcot-Marie-Tooth disease, the later benefited while the former did not show benefit; therefore, it depends on the disease Other management routes for NMD should be based on medicinal and surgical procedures, again depending on the underlying cause.

Since December 2016, autosomal recessive proximal spinal muscular atrophy can be treated with nusinersen. No cure is known to any of the remaining disorders of the spinal muscular atrophies group. The main objective there is to improve quality of life which can be measured using specific questionnaires. Supportive therapies are widely employed for patients who often also require comprehensive medical care involving multiple disciplines, including pulmonology, neurology, orthopedic surgery, critical care, and clinical nutrition. Various forms of physiotherapy and occupational therapy are frequently able to slow down the pace of nerve degeneration and muscle wasting. Patients also benefit greatly from the use of assistive technology.

In order to qualify a patient's condition as BSS, the bending angle must be greater than 45 degrees. While the presence of the condition is very easy to note, the cause of the condition is much more difficult to discern. Conditions not considered to be BSS include vertebral fractures, previously existing conditions, and ankylosing spondylitis. Lower-back CT scans and MRIs can typically be used to visualize the cause of the disease. Further identification of the cause can be done by histochemical or cellular analysis of muscle biopsy.

Camptocormia is becoming progressively found in patients with Parkinson's disease.

The diagnosis of Parkinson's-associated camptocormia includes the use of imaging of the brain and the spinal cord, along with electromyography or muscle biopsies.

Muscle biopsies are also a useful tool to diagnose camptocormia. Muscle biopsies found to have variable muscle fiber sizes and even endomysial fibrosis may be markers of bent spine syndrome. In addition, disorganized internal architecture and little necrosis or regeneration is a marker of camptocormia.

Patients with camptocormia present with reduced strength and stooped posture when standing due to weakened paraspinous muscles (muscles parallel to the spine). Clinically, limb muscles show fatigue with repetitive movements. Paraspinous muscles undergo fat infiltration. Electromyography may be used as well in diagnosis. On average, the paraspinous muscles of affected individuals were found to be 75% myopathic, while limb muscles were 50% percent myopathic. Creatine kinase activity levels in skeletal muscle are a diagnostic indicator that can be identifiable through blood tests.

The diagnosis is based on observing the patient and finding the constellation of symptoms and signs described above. A few blood tests help, by showing signs of long standing inflammation. There is no specific test for the disease, though now that the gene that causes the disease is known, that may change.

Routine laboratory investigations are non specific: anaemia, increased numbers of polymorphs, an elevated erythrocyte sedimentation rate and elevated concentrations of C-reactive protein are typically all the abnormalities found. Lumbar puncture shows elevated levels of polymorphs (20-70% of cases) and occasionally raised eosinophil counts (0-30% of cases). CSF neopterin may be elevated.

The X ray changes are unique and charactistic of this syndrome. These changes include bony overgrowth due to premature ossification of the patella and the long bone epiphyses in very young children and bowing of long bones with widening and shortening periosteal reaction in older ones.

Audiometry shows a progressive sensineural deafness. Visual examination shows optic atrophy and an increase in the blind spot. CT is usually normal but may show enlargement of the ventricles. MRI with contrast may show enhancement of leptomeninges and cochlea consistent with chronic meningitis. EEG shows is non specific with slow waves and spike discharges.

Polymorphs tend to show increased expression of CD10.

A diagnosis is made by measuring the enzymatic activity of alpha--mannosidase in white blood cells. If there is a decreased level of the enzyme in comparison to standard levels, a diagnosis can be made. It is thought that this disorder might be under-diagnosed for a few different reasons—the diagnosis is often made late in the disease's progression, symptoms are often mild, or the biochemical diagnosis does not yield conclusive results.

The clinical course of BVVL can vary from one patient to another. There have been cases with progressive deterioration, deterioration followed by periods of stabilization, and deterioration with abrupt periods of increasing severity.

The syndrome has previously been considered to have a high mortality rate but the initial response of most patients to the Riboflavin protocol are very encouraging and seem to indicate a significantly improved life expectancy could be achievable. There are three documented cases of BVVL where the patient died within the first five years of the disease. On the contrary, most patients have survived more than 10 years after the onset of their first symptom, and several cases have survived 20–30 years after the onset of their first symptom.

Families with multiple cases of BVVL and, more generally, multiple cases of infantile progressive bulbar palsy can show variability in age of disease onset and survival. Dipti and Childs described such a situation in which a family had five children that had Infantile PBP. In this family, three siblings showed sensorineural deafness and other symptoms of BVVL at an older age. The other two siblings showed symptoms of Fazio-Londe disease and died before the age of two.

Still's disease does not affect children under 6 months old.

Hyperimmunoglobulin D syndrome in 50% of cases is associated with mevalonate kinase deficiency which can be measured in the leukocytes.

The life expectancy in alpha-mannosidosis is highly variable. Individuals with early onset severe disease often do not survive beyond childhood, whereas those with milder disorders may survive well into adult life.

MDDS is diagnosed based on systemic symptoms presenting in infants, followed by a clinical examination and laboratory tests (for example, high lactate levels are common) medical imaging, and usually is finally confirmed and formally identified by genetic testing.

X-linked spinal muscular atrophy type 2 (SMAX2, XLSMA), also known as arthrogryposis multiplex congenita X-linked type 1 (AMCX1), is a rare neurological disorder involving death of motor neurons in the anterior horn of spinal cord resulting in generalised muscle wasting (atrophy). The disease is caused by a mutation in "UBA1" gene and is passed in a X-linked recessive manner by carrier mothers to affected sons.

Affected babies have general muscle weakness, weak cry and floppy limbs; consequently, the condition is usually apparent at or even before birth. Symptoms resemble the more severe forms of the more common spinal muscular atrophy (SMA); however, SMAX2 is caused by a different genetic defect and only genetic testing can correctly identify the disease.

The disorder is usually fatal in infancy or early childhood due to progressive respiratory failure, although survival into teenage years have been reported. As with many genetic disorders, there is no known cure to SMAX2. Appropriate palliative care may be able to increase quality of life and extend lifespan.