spinal muscular atrophy with lower extremity predominant 1

Spinal muscular atrophy with lower extremity predominance (SMA-LED) is a rare genetic disorder that primarily affects the lower limbs, causing muscle weakness and wasting in this region.

Characteristics:

• Muscle weakness and wasting in the lower limbs [1]
• Symptoms most pronounced in the large muscles of the thighs (quadriceps) [6]
• Can be present at birth or develop in early childhood [8]

Causes:

• Caused by a mutation in the survival motor neuron 2 (SMN2) gene, leading to malfunctioning motor neurons [5]
• Autosomal dominant inheritance pattern, meaning only one copy of the mutated gene is needed for the condition to manifest [7]

Symptoms:

• Muscle weakness and wasting in the lower limbs
• Symptoms can be non-progressive, meaning they do not worsen over time

It's essential to note that SMA-LED is a rare form of spinal muscular atrophy, and its symptoms may vary from person to person. If you or someone you know has been diagnosed with this condition, it's crucial to consult with a healthcare professional for proper guidance and care.

References: [1] Feb 1, 2019 — Spinal muscular atrophy with lower extremity predominance (SMA-LED) is characterized by muscle weakness and wasting (atrophy) in the lower limbs. [5] SMA-LED causes motor neurons to malfunction, resulting in weakness in leg muscles, which is most severe in the thigh muscles (quadriceps). Children and adults ... [6] Mar 3, 2023 — SMA-LED is characterized by muscle weakness in the lower limbs, with symptoms most pronounced in the large muscles of the thighs (quadriceps). [7] by HG Tekin · 2022 · Cited by 3 — Autosomal dominant SMA-LED is characterized by non-progressive congenital or early-onset lower limb predominant weakness and wasting caused by a mutation in ... [8] Description. SMALED2A is an autosomal dominant form of spinal muscular atrophy characterized by early childhood onset of muscle weakness and atrophy ...

Spinal Muscular Atrophy (SMA) with Lower Extremity Predominance

Individuals affected by SMA with lower extremity predominance often exhibit a range of symptoms, primarily affecting the muscles in their lower limbs. The severity and progression of these symptoms can vary significantly between people.

• Muscle Weakness: Muscle weakness is predominantly proximal (close to the center of the body) and involves the lower limbs more than the upper limbs [2]. This can lead to difficulties with walking, balance, and rising from a seated position.
• Waddling or Unsteady Walk: Affected individuals may have a waddling or unsteady walk due to muscle weakness in their legs [1].
• Muscle Atrophy: Muscle atrophy (wasting) is common in the lower limbs, leading to decreased muscle mass and strength [2].
• Difficulty Rising from Seated Position: Individuals with SMA may experience difficulty rising from a seated position due to muscle weakness in their lower extremities [1].

It's essential to note that symptoms can vary in severity between individuals. Early diagnosis and treatment are crucial for managing the condition and improving quality of life.

References: [1] - Context result 1: Feb 1, 2019 [2] - Context result 2: Oct 20, 2021

Spinal muscular atrophy with lower extremity predominance (SMA-LED) can be diagnosed through a combination of physical examination, medical history, and genetic testing.

• Physical Exam: A thorough physical exam is essential to assess muscle weakness and wasting in the lower limbs. The quadriceps muscles are most severely affected [3].
• Medical History: Reviewing the patient's health history, including any family history of neuromuscular disorders, can provide valuable information for diagnosis.
• Genetic Testing: Genetic testing is a crucial diagnostic tool for SMA-LED. It involves analyzing the SMN1 gene to identify mutations that cause the condition [7]. This blood test can confirm 95% of SMA cases by identifying problems with the SMN1 gene [8].
• Electromyography and Nerve Conduction Studies: These tests may be performed to assess muscle function and nerve conduction in the lower limbs. A muscle biopsy may also be done, especially if no gene changes were found [9].

It's worth noting that diagnosis of SMA-LED can be challenging, and a combination of these diagnostic tests is often necessary to confirm the condition.

References: [3] - Context 3 [7] - Context 5 [8] - Context 7 [9] - Context 9

Spinal Muscular Atrophy (SMA) with Lower Extremity Predominance (SMA-LED): Current Drug Treatment Options

Spinal muscular atrophy with lower extremity predominance (SMA-LED) is a rare and severe form of spinal muscular atrophy, characterized by muscle weakness and wasting in the lower limbs. While there are no disease-modifying gene therapies available for SMA-LED, several medications have been shown to improve muscle function and manage symptoms.

• Physical therapy: Physical therapy can be used to preserve range of motion and improve muscle strength in affected individuals (8).
• Medications: Although there are no current medications specifically approved for the treatment of spinal muscular atrophy with lower extremity predominance, several medications have been shown to increase SMN transcription in laboratory studies (3). These include valproic acid, phenylbutyrate, hydroxyurea, and albuterol.
• Spinraza: Spinraza is an antisense oligonucleotide designed to treat SMA caused by mutations in chromosome 5q that leads to SMN protein deficiency. However, it is not specifically approved for the treatment of SMA-LED (4).

It's essential to note that no treatment can currently reverse or cure SMA-LED, and disease-modifying gene therapies are not available for this condition (5). Therefore, management of symptoms and improving quality of life through physical therapy and other supportive measures remain the primary focus of care.

References:

• [2] Spinal muscular atrophy with lower extremity predominance (SMA-LED) is characterized by muscle weakness and wasting in the lower limbs.
• [3] Medications such as valproic

Understanding Differential Diagnosis for Spinal Muscular Atrophy (SMA) with Lower Extremity Predominance

Spinal muscular atrophy (SMA) is a group of genetic diseases that lead to progressive muscle weakness and atrophy. When it comes to SMA with lower extremity predominance, differential diagnosis plays a crucial role in identifying the condition accurately.

Key Conditions to Consider:

• Charcot-Marie-Tooth disease (CMT): This is another neuromuscular disorder that can present with similar symptoms to SMA-LED. CMT affects the peripheral nerves and muscles, leading to muscle weakness and atrophy.
• Muscular dystrophies: These are a group of genetic disorders that affect muscle strength and function. Some forms of muscular dystrophy can present with similar symptoms to SMA-LED.
• Spinal & bulbar muscular atrophy (Kennedy disease): This is an adult-onset form of SMA that affects the proximal muscles, leading to muscle weakness and atrophy.

Differential Diagnosis Considerations:

When considering differential diagnosis for SMA-LED, it's essential to take into account the following factors:

• Age of onset: SMA-LED typically presents in infancy or early childhood.
• Muscle distribution: The condition primarily affects the lower extremities, with the thigh muscles (quadriceps) being most severely affected.
• Progression rate: SMA-LED is characterized by a slow and progressive course.

Accurate Diagnosis:

A crucial step in accurate diagnosis is to consider these factors and rule out other conditions that may present with similar symptoms. This requires a comprehensive evaluation, including clinical examination, laboratory tests, and imaging studies.

References:

• [1] Prior TW. Spinal muscular atrophy. In: GeneReviews [Internet]. Seattle (WA): University of Washington; 2019.
• [2] Aziz I. Spinal muscular atrophy with lower extremity dominance. In: GeneReviews [Internet]. Seattle (WA): University of Washington; 2022.
• [3] Scoto M, et al. A DYNC1H1 mutation causing spinal muscular atrophy with lower limb predominance. Neuromuscul Disord. 2019;29(10):751-755.

By considering these factors and conditions, healthcare professionals can make an accurate diagnosis of SMA-LED and provide appropriate management and care for affected individuals.