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Spinal Muscular Atrophy Type 2



  • Severity of SMA is related to the number of SMN2 copies present. SMA type 1 patients usually have 2 copies of SMN2 , while type IV patients usually have 3-4 copies. Inheritance : Autosomal recessive.[genetics4medics.com]
  • These children present with significant weakness and generalized hypotonia which manifests in difficulty moving, swallowing, feeding and breathing. The neck, shoulder girdle, chest and pelvis demonstrate the greatest weakness.[columbiasma.org]
  • CLINICAL CLASSIFICATION: Based on age of onset and functional capacity at time of presentation .[gait.aidi.udel.edu]
  • These patients present by hypotonia, symmetrical flaccid paralysis, no head control and poor suck and swallow, with increasing swallowing and feeding difficulty over time due to involvement of bulbar motoneurons. They present before 6 months of age.[raredisorders.imedpub.com]
  • Classification Type Name Presentation Prognosis Type I Acute Werdnig-Hoffman disease • Present at 6 months • Absent DTR • Tongue fasciculations Poor, usually die by 2 yrs.[orthobullets.com]
  • The investigation results were: WBC: 13.9; HB:11; PLT: 445; creatinine: 21; Na:142; K: 3.5, blood culture was staphylococcus epidermidis, and the chest x-ray showed right upper lobe collapse, then left lung collapse and both resolved.[raredisorders.imedpub.com]
Recurrent Upper Respiratory Infection
  • Past medical history significant for recurrent upper respiratory infections occasionally requiring hospitalization.[gait.aidi.udel.edu]
Decreased Breath Sounds
  • At this time she looked alert, having sever ehypotonia, frog like position, seesaw breathing, with decreased breath sounds on the right side of the chest. The case was admitted to PICU and connected to mechanical ventilation.[raredisorders.imedpub.com]
  • One is choking. Choking is possible because a child with SMA has weak swallowing and chewing muscles. Another risk is aspiration or inhaling of food. Aspiration can block the airway as well as be a source of infection.[verywell.com]
  • His lumbar lordosis associated with anterior tilted pelvis and his problems with head balance due to weak neck musculature caused compensatory behavior like a retracted neck and mandible.[ncbi.nlm.nih.gov]
  • Airway management was further complicated by limited mouth opening and cervical spine ankylosis. Copyright 2017 Elsevier Ltd. All rights reserved. KEYWORDS: Airway; Dexmedetomidine; Spinal muscular atrophy[ncbi.nlm.nih.gov]
Long Leg
  • Managed with physical therapy and inpatient rehabilitation consisting of intensive physical, occupational and aquatic therapy and the use of long leg braces at age of 2.[gait.aidi.udel.edu]
Hand Tremor
  • Muscle cramps, facial fasciculations, hand tremor. Associated with type 2 diabetes and infertility.[patient.info]
  • Type 2 diabetes mellitus, hand tremor, and infertility can also occur. Bulbar involvement predisposes the person with spinal muscular atrophy to recurrent aspiration pneumonia, due to weakening of the muscles necessary for efficient swallowing.[encyclopedia.com]
Neonatal Hypotonia
  • Sometimes onset is prenatal and presents with neonatal hypotonia and contractures. Never acquire ability to sit without support. usually do not survive beyond the first 2 years of life. Type II : Intermediate type. Onset between 7-18 months of age.[genetics4medics.com]
Gowers Sign
  • sign secondary to proximal muscle weakness with pseudohypertrophy of claves CLINICAL FEATURES: Symmetric limb and trunk weakness with muscle atrophy greater in the lower extremities than the upper extremities; and greater atrophy in the proximal muscle[gait.aidi.udel.edu]


  • Our result demonstrates that administration of BTA is one of the effective treatment choices for dysphagia in SMA patients.[ncbi.nlm.nih.gov]
  • All types of SMA need ongoing treatment by a medical care team. There's no cure for SMA, but treatments can help children with SMA live a better life. What Happens in SMA? In SMA, the nerves that control muscle strength and movement break down.[kidshealth.org]
  • , pelvic alignment and increase comfort Some authors recommend treatment of dislocated hips however the redislocation rate has proven to be significant due to the progressive degeneration of the proximal muscles (8) Others recommend symptomatic treatment[gait.aidi.udel.edu]
  • The mission of the Spinal Muscular Atrophy Foundation is to accelerate the development of a treatment for SMA[smafoundation.org]


  • Prognosis The prognosis depends on the severity of the disease, which generally correlates with the age of onset: earlier-onset forms are generally associated with a poor prognosis, whereas life expectancy may be close to normal in later-onset forms.[rarediseases.info.nih.gov]
  • prognosis of these patients 7,8.[radiopaedia.org]
  • The most promising prognosis comes about with early detection. Advances in medicine can help manage the complications associated with SMA.[verywell.com]
  • Prognosis The prognosis is generally poor with most patients dying within the first two years of life due to respiratory failure. However, in some cases, manifestations are stable or even regress, and patients may live longer.[orpha.net]


  • Etiology Pathophysiology Clinical features The most common causes of death among patients with SMA are respiratory insufficiency (due to respiratory muscle weakness ) and aspiration pneumonia (due to bulbar weakness)![amboss.com]
  • The most common form of spinal muscular atrophy (SMA) is a recessive disorder caused by deleterious SMN1 mutations in 5q13, whereas the genetic etiologies of non-5q SMA are very heterogeneous and largely remain to be elucidated.[uniprot.org]
  • Etiology As for the other forms of SMA, SMA4 has been associated with deletions in the SMN1 gene (5q12.2-q13.3) encoding the SMN (survival motor neuron) protein.[orpha.net]


  • Epidemiology References: [1] [2] [3] Epidemiological data refers to the US, unless otherwise specified.[amboss.com]
  • Summary Epidemiology Prevalence is estimated at around 1/300,000. Clinical description SMA4 usually manifests in the second or third decade of life.[orpha.net]
  • Epidemiology Prevalence is estimated at around 1/30,000.[rarediseases.info.nih.gov]
Sex distribution
Age distribution


  • Identification of the molecular pathophysiology of lower motor neuron syndromes can be expected to aid in the development of therapy for these disabling disorders.[dpag.ox.ac.uk]
  • Etiology Pathophysiology Clinical features The most common causes of death among patients with SMA are respiratory insufficiency (due to respiratory muscle weakness ) and aspiration pneumonia (due to bulbar weakness)![amboss.com]
  • Pathophysiology Spinal muscular atrophy (SMA) types I-III Inheritance is autosomal recessive. Affected individuals have two copies of the altered gene. Those who carry one copy are usually unaffected carriers.[patient.info]
  • Pathophysiology In 1995, the spinal muscular atrophy disease-causing gene, termed the survival motor neuron ( SMN ), was discovered. [9] Each individual has 2 SMN genes, SMN1 and SMN2.[emedicine.medscape.com]


  • This article discusses the primary respiratory complications of spinal muscular atrophy type 2 and the role of respiratory interventions to promote growth and development, improve cough efficacy, reverse nocturnal hypoventilation, and prevent and treat[ncbi.nlm.nih.gov]
  • Long posterior fusion was the best way to prevent secondary curves above and below the fusion 2. Anterior arthrodesis alone was not sufficient to maintain spinal stability 3.[gait.aidi.udel.edu]
  • If a breathing machine is needed, a tube may be placed into the windpipe (called a tracheostomy ). treatments to help kids cough and clear mucus, which can help prevent infections proper nutrition.[kidshealth.org]
  • Activity is not to be avoided, but rather used in such a way as to prevent deformity, contracture, and stiffness and to preserve range of motion and flexibility. Therefore, it should not be done to the point of exhaustion.[verywell.com]
  • Some babies with SMA1 may not respond to the nusinersen at all or may have medical complications that prevent use of the treatment. [3] [4] Other treatments remain supportive. [5] [6] Last updated: 8/25/2018[rarediseases.info.nih.gov]

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