Peroneal muscular atrophy

Neurology

Clinicals - History

Fact Explanation
Introduction Peroneal muscular atrophy is a type of hereditary motor neuropathy that has the autosomal dominant inheritance. Some describes it as type V hereditary motor and sensory neuropathy. This is different from the hereditary motor and sensory neuropathy as this has no sensory symptoms. Genetic factor may be related to the missense mutations in several genes coding for structural myelin proteins, gap-junction proteins, cytoskeleton components, enzymes, or transcription factor. Diseases can be classified into demyelinating (CMT1 and CMT4), axonal (CMT2 and CMT4), and intermediate (CMT, CMTX, CMT2E) forms. Onset is usually in the first two decades of life. It is associated with pyramidal features and presents with difficulty in walking. It is slowly progressive and may be associated with some degree of disability. Introduction
Peroneal muscular atrophy is a type of hereditary motor neuropathy that has the autosomal dominant inheritance. Some describes it as type V hereditary motor and sensory neuropathy. This is different from the hereditary motor and sensory neuropathy as this has no sensory symptoms. Genetic factor may be related to the missense mutations in several genes coding for structural myelin proteins, gap-junction proteins, cytoskeleton components, enzymes, or transcription factor. Diseases can be classified into demyelinating (CMT1 and CMT4), axonal (CMT2 and CMT4), and intermediate (CMT, CMTX, CMT2E) forms. Onset is usually in the first two decades of life. It is associated with pyramidal features and presents with difficulty in walking. It is slowly progressive and may be associated with some degree of disability.
Difficulty in walking Distal wasting and weakness is the prominent feature and presents with weakness involving the legs more than the arms. Difficulty in walking is the initial manifestation of the disease. There can be peroneal and anterior tibial muscle involvement. Significant weakness in dorsiflexors of legs leading to foot drop may be a main contributory factor. Difficulty in walking
Distal wasting and weakness is the prominent feature and presents with weakness involving the legs more than the arms. Difficulty in walking is the initial manifestation of the disease. There can be peroneal and anterior tibial muscle involvement. Significant weakness in dorsiflexors of legs leading to foot drop may be a main contributory factor.
Loss of function There can be pyramidal tract involvement due to the hypertrophied nerve roots compressing the spinal cord. It causes some degree of disability, but is not a severe disability. Loss of function
There can be pyramidal tract involvement due to the hypertrophied nerve roots compressing the spinal cord. It causes some degree of disability, but is not a severe disability.
Sensory sumptoms Usually there are no sensory impaiment. Sensory sumptoms
Usually there are no sensory impaiment.
Family history Autosomal dominant mode of inheritance is seen among the family members, starting at the early adult life. Occasionally recessive inheritance is also noted. Family history
Autosomal dominant mode of inheritance is seen among the family members, starting at the early adult life. Occasionally recessive inheritance is also noted.
Shortness of breath and respiratory problems Cardiac tissue involvement is an occasional complication of the disease. Diaphragmatic paralysis is seen in these patients. Shortness of breath and respiratory problems
Cardiac tissue involvement is an occasional complication of the disease. Diaphragmatic paralysis is seen in these patients.
Speach difficulties Due to the associated vocal cord paralysis. Speach difficulties
Due to the associated vocal cord paralysis.
Symptoms of depressision : such as fatigue and sleep disturbances Depression is common among patients with neuromuscular problems. Symptoms of depressision : such as fatigue and sleep disturbances
Depression is common among patients with neuromuscular problems.

Clinicals - Examination

Fact Explanation
Wasting Is more prominent in the distal parts of the limbs particularly in muscles of the calves and feet. Upper limb involvement is less frequent, but can involved in the latter part of he disease. There are main two varieties of the disease , one presents with spasticity and marked muscle wasting and the other with spasticity and amyotrophy. Amyotrophy is the progressive wasting of muscle tissues. Wasting
Is more prominent in the distal parts of the limbs particularly in muscles of the calves and feet. Upper limb involvement is less frequent, but can involved in the latter part of he disease. There are main two varieties of the disease , one presents with spasticity and marked muscle wasting and the other with spasticity and amyotrophy. Amyotrophy is the progressive wasting of muscle tissues.
Tone Increased tone is due to the pyramidal involvement caused by compression of the spinal cord by hypertrophied nerve roots. Studies have shown that there is a corticospinal tract degeneration as a pathological finding in these patients. Tone
Increased tone is due to the pyramidal involvement caused by compression of the spinal cord by hypertrophied nerve roots. Studies have shown that there is a corticospinal tract degeneration as a pathological finding in these patients.
Power Weakness is mainly in the distal parts of the lower limbs. If the disease has theonset in early infancy (Dejerine–Sottas and congenital hypomyelination diseases) there can be hypotonia and delay in motor milestones. Power
Weakness is mainly in the distal parts of the lower limbs. If the disease has theonset in early infancy (Dejerine–Sottas and congenital hypomyelination diseases) there can be hypotonia and delay in motor milestones.
Tendon reflexes Upper limb reflexes and knee reflexes will be either normal or increased, but the ankle jerks are often absent. Knee jerk may be exaggerated due to the involvement of corticospinal tracts. Ankle jerk may be depressed due to the distal muscle weakness. Tendon reflexes in the arm may be normal or brisk at times. Tendon reflexes
Upper limb reflexes and knee reflexes will be either normal or increased, but the ankle jerks are often absent. Knee jerk may be exaggerated due to the involvement of corticospinal tracts. Ankle jerk may be depressed due to the distal muscle weakness. Tendon reflexes in the arm may be normal or brisk at times.
Plantar responses Pyramidal signs may present. Plantar responses may be extensor. Occasionally may be absent or flexor. Plantar responses
Pyramidal signs may present. Plantar responses may be extensor. Occasionally may be absent or flexor.
Contractures Distal contractures are observed in these patients. Contractures
Distal contractures are observed in these patients.
Foot drop and high stepping gait Significant weakness in dorsiflexors of legs leading to foot drop may be foundin these patients. When the weakness becomes more severe, foot drop commonly occurs and gait will be abnormal. Foot drop and high stepping gait
Significant weakness in dorsiflexors of legs leading to foot drop may be foundin these patients. When the weakness becomes more severe, foot drop commonly occurs and gait will be abnormal.
Pes cavus / pes planus and scoliosis High arched feet that does not flatten with weight bearing (pes cavus) or flat arched feet (pes planus) is present. Pes cavus is caused by peroneus longus overpower weak tibialis anterior and may be associated with hammer toe. Pes planus is due to the loss of the medial longitudinal arch and it may be either rigid or flexible. Pes cavus / pes planus and scoliosis
High arched feet that does not flatten with weight bearing (pes cavus) or flat arched feet (pes planus) is present. Pes cavus is caused by peroneus longus overpower weak tibialis anterior and may be associated with hammer toe. Pes planus is due to the loss of the medial longitudinal arch and it may be either rigid or flexible.
Sensation There can be features of sensorimotor peripheral neuropathy. Vibration and proprioception are diminished , but no significant sensory impairment. Sensation
There can be features of sensorimotor peripheral neuropathy. Vibration and proprioception are diminished , but no significant sensory impairment.
Irregular heart rate, bradycardia Bradycardia, irregular rhythm, atrial fibrillation and flutter are the cardiac defects due to the involvement of the cardiac tissue. Irregular heart rate, bradycardia
Bradycardia, irregular rhythm, atrial fibrillation and flutter are the cardiac defects due to the involvement of the cardiac tissue.
Dyspnea May be due to the cardiomyopathy which is a known complication of the disease. Diaphragmatic paralysis is also seen in these patients. Dyspnea
May be due to the cardiomyopathy which is a known complication of the disease. Diaphragmatic paralysis is also seen in these patients.
Changes in voice Vocal cord paralysis is seen in some patients with hereditory sensory motor polyneuropathy. Changes in voice
Vocal cord paralysis is seen in some patients with hereditory sensory motor polyneuropathy.
Low mood Depression is common among patients with neuromuscular problems. Low mood
Depression is common among patients with neuromuscular problems.

Investigations - Diagnosis

Fact Explanation
Motor nerve conduction velocity Motor nerve conduction velocity is reduced. I t will be defined as <38 m/s in upper limb motor nerves. Motor nerve conduction velocity
Motor nerve conduction velocity is reduced. I t will be defined as <38 m/s in upper limb motor nerves.
Sensory nerve action potential As this is a type of hereditory motor neuropathy , sensations are usually normal, but the sensory nerve action potentials may be either reduced or absent in certain patients. Sensory nerve action potential
As this is a type of hereditory motor neuropathy , sensations are usually normal, but the sensory nerve action potentials may be either reduced or absent in certain patients.
Muscle biopsy Should be done in all patients with suspected disease. This will show normal fascicular architecture, marked variation in fiber size, hypertrophic fibers, split fibers and angulated atrophic fibers with significant degenerating and regenerating muscle fibers, with central nuclei. Muscle biopsy
Should be done in all patients with suspected disease. This will show normal fascicular architecture, marked variation in fiber size, hypertrophic fibers, split fibers and angulated atrophic fibers with significant degenerating and regenerating muscle fibers, with central nuclei.
Creatine kinase (CK) Creatine kinase (CK) is elevated in the plasma. Normal value would be <200 IU/L. Creatine kinase (CK)
Creatine kinase (CK) is elevated in the plasma. Normal value would be <200 IU/L.

Investigations - Management

Fact Explanation
Creatinine kinase The level will be elevated and need to monitor as the disease progresses. Creatinine kinase
The level will be elevated and need to monitor as the disease progresses.
Respiratory functions: vital capacity, single breath count Monitoring the respiratory function is important as they can develop respiratory failure as a predominant complication. Respiratory functions: vital capacity, single breath count
Monitoring the respiratory function is important as they can develop respiratory failure as a predominant complication.
Electrocardiogram Annual ECG may be important to detect asymptomatic cardiac defects. Electrocardiogram
Annual ECG may be important to detect asymptomatic cardiac defects.
Electrocardiogram Low amplitude P waves and a prolonged PR interval are the initial changes followed by junctional escape rhythm, bradycardia, absent P waves, atrial fibrillation, atrial flutter and complete heart block. Electrocardiogram
Low amplitude P waves and a prolonged PR interval are the initial changes followed by junctional escape rhythm, bradycardia, absent P waves, atrial fibrillation, atrial flutter and complete heart block.
2D Echocardiogram Patients are likely to present with features of cardiac failure due to various causes. eg:- Diaphragmatic paralysis may cause nocturnal hypoventilation, Cardiac problems which are not due to the conduction tissue diseases such as valvular problems, cardiomyopathies and ischaemic events has to be evaluated to recognize and treat the potential cause of the presentation. Assessment of left ventricular structure and function is commonly idone using 2D echocardiography. 2D Echocardiogram
Patients are likely to present with features of cardiac failure due to various causes. eg:- Diaphragmatic paralysis may cause nocturnal hypoventilation, Cardiac problems which are not due to the conduction tissue diseases such as valvular problems, cardiomyopathies and ischaemic events has to be evaluated to recognize and treat the potential cause of the presentation. Assessment of left ventricular structure and function is commonly idone using 2D echocardiography.
Electrocardiogram Abnormalities in the cardiac conducting tissue is associated with the peroneal muscular atrophy. Low amplitude P waves and a prolonged PR interval are the initial changes followed by junctional escape rhythm, bradycardia, absent P waves, atrial fibrillation and flutter. Electrocardiogram
Abnormalities in the cardiac conducting tissue is associated with the peroneal muscular atrophy. Low amplitude P waves and a prolonged PR interval are the initial changes followed by junctional escape rhythm, bradycardia, absent P waves, atrial fibrillation and flutter.
Magnetic Resonance Imaging of the limbs This provides multiple images for each segment, that is important in assessing the individual muscles and their involvement. Magnetic resonance imaging (MRI) of limbs will show generalized hyperintense signal in in affected muscles. Quadriceps muscles are usually spared. Magnetic Resonance Imaging of the limbs
This provides multiple images for each segment, that is important in assessing the individual muscles and their involvement. Magnetic resonance imaging (MRI) of limbs will show generalized hyperintense signal in in affected muscles. Quadriceps muscles are usually spared.
Genetic studies Mutational analysis can be done to assess the associated underlying missense mutations. Genetic studies
Mutational analysis can be done to assess the associated underlying missense mutations.

Management - Supportive

Fact Explanation
Patient education Patient should be educated about thye disease, complications and management options. This will enhance the compliance to the required therapies like physiotherapy and occupational therapy. Patient education
Patient should be educated about thye disease, complications and management options. This will enhance the compliance to the required therapies like physiotherapy and occupational therapy.
Physical activities It is important to maintain the movements, muscle strength, and flexibility as they are prone to get complications. Orthotics or ankle bracing is the is one of the important steps in making the patient ambulatory. Activities are recommended in moderate amount with avoiding over exertion. Over exertion is avoided as extraneous physical activities can even cause limb paralysis. Physical activities
It is important to maintain the movements, muscle strength, and flexibility as they are prone to get complications. Orthotics or ankle bracing is the is one of the important steps in making the patient ambulatory. Activities are recommended in moderate amount with avoiding over exertion. Over exertion is avoided as extraneous physical activities can even cause limb paralysis.
Avoiding exacerbating factors Emotional stress is known to exacerbate the disease and therefore needs to be controlled. Prolonged immobility may also accelerate the symptoms of neuromuscular disorders. Avoiding exacerbating factors
Emotional stress is known to exacerbate the disease and therefore needs to be controlled. Prolonged immobility may also accelerate the symptoms of neuromuscular disorders.
Caution with certain drugs Vincristine which is commonly used in the chemotherapy of lymphoma is a well known drug to adversly affect these patients, exacerbating the symptoms. Amiodarone, cisplatin & Oxaliplatin, dapsone , didanosine, gold salt and leflunomide are other drugs that increase the adverse effects on thees patients. Therefore measures should be taken to avoid these. Caution with certain drugs
Vincristine which is commonly used in the chemotherapy of lymphoma is a well known drug to adversly affect these patients, exacerbating the symptoms. Amiodarone, cisplatin & Oxaliplatin, dapsone , didanosine, gold salt and leflunomide are other drugs that increase the adverse effects on thees patients. Therefore measures should be taken to avoid these.
Management of associated conditions Scoliosis may be present in 10% of patients with peroneal atrophy. It is managed by nonoperative
bracing or operative fusion and instrumentation in the presence of progressive deformity. Pes cavus stands for high arched foot that does not flatten with bearing weight. Management of cavus deformity involves nonoperative stretching, strengthening, and orthotics and operative measures. Nonsteroidal anti inflammatory medications can be helpful to accompanied. Pain may also respond to strengthening weakened ankles and correcting foot deformities.
Management of associated conditions
Scoliosis may be present in 10% of patients with peroneal atrophy. It is managed by nonoperative
bracing or operative fusion and instrumentation in the presence of progressive deformity. Pes cavus stands for high arched foot that does not flatten with bearing weight. Management of cavus deformity involves nonoperative stretching, strengthening, and orthotics and operative measures. Nonsteroidal anti inflammatory medications can be helpful to accompanied. Pain may also respond to strengthening weakened ankles and correcting foot deformities.
Psychological support Patients with neuromuscular problems are vulnerable for psychological problems particularly depression and anxiety. Therefore early attention and treatment is important to prevent recurrances and disability. Psychological support
Patients with neuromuscular problems are vulnerable for psychological problems particularly depression and anxiety. Therefore early attention and treatment is important to prevent recurrances and disability.
Genetic counseling As this has a genetic basis for the aetiology, counseling the individual and familiy with on the genetic nature of the disaese , inheritance, and implications of genetic disorder is particularly helpful them to involve in the decision making. Genetic counseling
As this has a genetic basis for the aetiology, counseling the individual and familiy with on the genetic nature of the disaese , inheritance, and implications of genetic disorder is particularly helpful them to involve in the decision making.

Management - Specific

Fact Explanation
Management options There is no cure for the condition, management is essentially supportive, based on a multidisciplinary approach. Therefore symptoms management, prevention and treatment of complications should be the focus of therapy.Physical therapy, occupational therapy are the mainstay of therapeutic options. Management options
There is no cure for the condition, management is essentially supportive, based on a multidisciplinary approach. Therefore symptoms management, prevention and treatment of complications should be the focus of therapy.Physical therapy, occupational therapy are the mainstay of therapeutic options.
Ventilatory support Respiratory failure is a recognized complication of the disease, which may be due to the diaphragmatic paralysis causing nocturnal hypoventilation necessitating artificial ventilation. Ventilatory support
Respiratory failure is a recognized complication of the disease, which may be due to the diaphragmatic paralysis causing nocturnal hypoventilation necessitating artificial ventilation.
Orthosis Distal wasting and weakness is the prominent feature and presents with weakness involving the legs more than the arms. Difficulty in walking is the initial manifestation of the disease. Significant weakness in dorsiflexors of legs leading to foot drop may be a main contributory factor. Therefore ankle-foot orthose mayy help to overcome the abnormalities in the gait. Custom-made shoes can be use to restore the balance of gait. Orthosis
Distal wasting and weakness is the prominent feature and presents with weakness involving the legs more than the arms. Difficulty in walking is the initial manifestation of the disease. Significant weakness in dorsiflexors of legs leading to foot drop may be a main contributory factor. Therefore ankle-foot orthose mayy help to overcome the abnormalities in the gait. Custom-made shoes can be use to restore the balance of gait.
Occupational therapy Occupational therapy is important to enable the person to engage in everyday living, through occupation, perform the occupation and living an independent life as much as possible. Dmiciliary occupational therapy can enhance recovery and also important to prevent further deterioration. Occupational therapy
Occupational therapy is important to enable the person to engage in everyday living, through occupation, perform the occupation and living an independent life as much as possible. Dmiciliary occupational therapy can enhance recovery and also important to prevent further deterioration.
Physiotherapy Regular physiotherapy is targeted to preservae the muscle power and function and to prevent contractures. Physiotherapy
Regular physiotherapy is targeted to preservae the muscle power and function and to prevent contractures.
Surgery Patients may various foot abnormalities such as pes cavus, foot drop and contractures etc. Surgical procedures may be required to straighten and pin the toes, lower the arch, and fuse the ankle joint to provide stability. This is done when the conservative measures are failed. Surgery
Patients may various foot abnormalities such as pes cavus, foot drop and contractures etc. Surgical procedures may be required to straighten and pin the toes, lower the arch, and fuse the ankle joint to provide stability. This is done when the conservative measures are failed.

Concise, fact-based medical articles to refresh your knowledge

Access a wealth of content and skim through a smartly presented catalog of diseases and conditions.

  1. BERTINI E, D'AMICO A, GUALANDI F, PETRINI S. Congenital Muscular Dystrophies: A Brief Review Semin Pediatr Neurol [online] 2011 Dec, 18(4):277-288 [viewed 16 September 2014] Available from: doi:10.1016/j.spen.2011.10.010
  2. CUP EH, KINéBANIAN A, SATINK T, PIETERSE AJ, HENDRICKS HT, OOSTENDORP RA, VAN DER WILT GJ, VAN ENGELEN BG. Living with myotonic dystrophy; what can be learned from couples? a qualitative study BMC Neurol [online] :86 [viewed 16 September 2014] Available from: doi:10.1186/1471-2377-11-86
  3. EMERY AE. The muscular dystrophies BMJ [online] 1998 Oct 10, 317(7164):991-995 [viewed 16 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC111404
  4. FRITH JA, MCLEOD JG, NICHOLSON GA, YANG F. Peroneal muscular atrophy with pyramidal tract features (hereditary motor and sensory neuropathy type V): a clinical, neurophysiological, and pathological study of a large kindred. J Neurol Neurosurg Psychiatry [online] 1994 Nov, 57(11):1343-1346 [viewed 15 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1073184
  5. GILBERTSON L, LANGHORNE P, WALKER A, ALLEN A, MURRAY GD. Domiciliary occupational therapy for patients with stroke discharged from hospital: randomised controlled trial BMJ [online] 2000 Mar 4, 320(7235):603-606 [viewed 16 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC27300
  6. HARDIE R, HARDING AE, HIRSCH N, GELDER C, MACRAE AD, THOMAS PK. Diaphragmatic weakness in hereditary motor and sensory neuropathy. J Neurol Neurosurg Psychiatry [online] 1990 Apr, 53(4):348-350 [viewed 22 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1014177
  7. HARDING AE, THOMAS PK. Peroneal muscular atrophy with pyramidal features. J Neurol Neurosurg Psychiatry [online] 1984 Feb, 47(2):168-172 [viewed 15 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1027687
  8. IROBI J.. Molecular genetics of distal hereditary motor neuropathies. Human Molecular Genetics [online] 2004 October, 13(suppl_2):R195-R202 [viewed 15 September 2014] Available from: doi:10.1093/hmg/ddh226
  9. JUNGBLUTH HEINZ, WALLGREN-PETTERSSON CARINA, LAPORTE JOCELYN. Centronuclear (myotubular) myopathy. Array [online] 2008 December [viewed 16 September 2014] Available from: doi:10.1186/1750-1172-3-26
  10. KANNAN MA, CHALLA S, URTIZBEREA AJ, KRAHN M, JABEEN AS, BORGOHAIN R. Distal myopathy with rimmed vacuoles and inflammation: a genetically proven case. Neurol India [online] 2012 Nov-Dec, 60(6):631-4 [viewed 16 September 2014] Available from: doi:10.4103/0028-3886.105199
  11. LEAK D. PAROXYSMAL ATRIAL FLUTTER IN PERONEAL MUSCULAR ATROPHY Br Heart J [online] 1961 May, 23(3):326-328 [viewed 15 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1017773
  12. LI J. Inherited Neuropathies Semin Neurol [online] 2012 Jul, 32(3):204-214 [viewed 22 September 2014] Available from: doi:10.1055/s-0032-1329198
  13. LOWRY PJ, LITTLER WA. Peroneal muscular atrophy associated with cardiac conducting tissue disease: further observations Postgrad Med J [online] 1983 Aug, 59(694):530-532 [viewed 15 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2417587
  14. MEHROTRA R, ALAGESAN R, SRIVASTAVA S. Quantitative assessment of left ventricular systolic function using 3-dimensional echocardiography Indian Heart J [online] 2013 Sep, 65(5):620-628 [viewed 22 September 2014] Available from: doi:10.1016/j.ihj.2013.08.027
  15. MEI ZHANYONG, ZHAO GUORU, IVANOV KAMEN, GUO YANWEI, ZHU QINGSONG, ZHOU YONGJIN, WANG LEI. Sample entropy characteristics of movement for four foot types based on plantar centre of pressure during stance phase. Array [online] 2013 December [viewed 16 September 2014] Available from: doi:10.1186/1475-925X-12-101
  16. NALINI A, GAYATHRI N, DAWN R. Distal myopathy with rimmed vacuoles: report on clinical characteristics in 23 cases. Neurol India [online] 2010 Mar-Apr, 58(2):235-41 [viewed 16 September 2014] Available from: doi:10.4103/0028-3886.63804
  17. PIAZZA S, RICCI G, CALDARAZZO IENCO E, CARLESI C, VOLPI L, SICILIANO G, MANCUSO M. Pes cavus and hereditary neuropathies: when a relationship should be suspected J Orthop Traumatol [online] 2010 Dec, 11(4):195-201 [viewed 22 September 2014] Available from: doi:10.1007/s10195-010-0114-y
  18. PONDER BA, CHATTERJEE K, SUTTON GC. Complete heart block in patients with peroneal muscular atrophy Postgrad Med J [online] 1971 Sep, 47(551):595-598 [viewed 15 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2467297
  19. SCHILLING LISA, FORST RAIMUND, FORST JüRGEN, FUJAK ALBERT. Orthopaedic Disorders in Myotonic Dystrophy Type 1: descriptive clinical study of 21 patients. Array [online] 2013 December [viewed 16 September 2014] Available from: doi:10.1186/1471-2474-14-33
  20. SOZUMI K. Linkage of scapuloperoneal spinal muscular atrophy to chromosome 12q24.1-q24.31. [online] 1996 September, 5(9):1377-1382 [viewed 16 September 2014] Available from: doi:10.1093/hmg/5.9.1377
  21. THOMAS PK, CALNE DB. Motor nerve conduction velocity in peroneal muscular atrophy: evidence for genetic heterogeneity J Neurol Neurosurg Psychiatry [online] 1974 Jan, 37(1):68-75 [viewed 15 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC494564
  22. WINBLAD STEFAN, JENSEN CHRISTER, MåNSSON JAN-ERIC, SAMUELSSON LENA, LINDBERG CHRISTOPHER. Depression in Myotonic Dystrophy type 1: clinical and neuronal correlates. Array [online] 2010 December [viewed 16 September 2014] Available from: doi:10.1186/1744-9081-6-25