spinal muscular atrophy with lower extremity predominant 2B

Spinal muscular atrophy with lower extremity predominant 2B (SMA-LED 2B) is a severe neuromuscular disorder that affects the lower limbs, causing muscle weakness and wasting. It is characterized by decreased fetal movements and is usually born with severe congenital joint contractures, arthrogryposis multiplex congenita, and fractures in utero [7].

SMA-LED 2B is a rare form of spinal muscular atrophy that begins in infancy or early childhood. The disease primarily affects the upper part of the legs (thighs), causing weakness and loss of muscle mass in the quadriceps muscles [4]. It is inherited in an autosomal dominant pattern, meaning that a single copy of the mutated gene is enough to cause the condition.

The heterozygous bicaudal D homolog 2 gene (BICD2) mutations are responsible for causing SMA-LED 2B [8]. This genetic mutation leads to the degeneration of motor neurons in the spinal cord, resulting in muscle weakness and wasting in the lower limbs.

In terms of description, SMA-LED 2B is a severe neuromuscular disorder that affects the lower extremities, causing significant muscle weakness and wasting. It is characterized by decreased fetal movements, fractures in utero, and severe congenital joint contractures [7].

Key characteristics:

• Muscle weakness and wasting in the lower limbs
• Decreased fetal movements
• Fractures in utero
• Severe congenital joint contractures
• Autosomal dominant inheritance pattern
• Heterozygous BICD2 gene mutations

References:

[4] Oct 20, 2021 — SMA-LED mostly affects the upper part of the legs (thighs), causing weakness and loss of muscle mass in the quadriceps (thigh muscles). [7] The disease is characterized by decreased fetal movements, fractures in utero, severe congenital joint contractures, arthrogryposis multiplex congenita, severe ... [8] by R Kulshrestha · 2017 — Heterozygous bicaudal D homolog 2 gene (BICD2) mutations cause a form of autosomal dominant spinal muscular atrophy with lower extremity predominance ...

Spinal muscular atrophy with lower extremity predominance (SMA-LED) is a genetic disorder that affects the muscles used for movement, leading to weakness and wasting in the lower limbs. The symptoms of SMA-LED can vary in severity between individuals, but they often include:

• Muscle weakness and wasting (atrophy) in the lower limbs [3]
• Progressive muscle weakness, floppiness, and muscle wasting (atrophy) [6]
• Weakness and wasting (atrophy) in muscles used for movement (skeletal muscles) [7]

In addition to these symptoms, individuals with SMA-LED may also experience:

• Delayed or failure to meet motor milestones [8]
• Muscle weakness that is usually the same on both sides of the body [6]

It's worth noting that the symptoms of SMA-LED can be mild or disabling, and may vary in severity between individuals. Early diagnosis and treatment are essential for managing the condition and improving quality of life.

References: [3] - Oct 20, 2021 — The symptoms of SMA-LED vary in severity between people, but they always include muscle weakness and muscle atrophy in the lower extremities, ... [6] - SMA symptoms may include progressive muscle weakness, floppiness, and muscle wasting (atrophy). Muscle weakness is usually the same on both sides of the body. [7] - Oct 1, 2018 — Spinal muscular atrophy is a genetic disorder characterized by weakness and wasting (atrophy ) in muscles used for movement (skeletal muscles). [8] - The first sign is often a delay in meeting motor milestones or failing to meet milestones entirely. Individuals with SMA Type 2 can typically sit up without ...

Spinal muscular atrophy with lower extremity predominance 2B (SMA-LED2B) is a rare neuromuscular

Spinal muscular atrophy with lower extremity predominance (SMA-LED) is a type of spinal muscular atrophy that primarily affects the muscles in the lower limbs. While there are no current medications specifically approved for the treatment of SMA-LED, several disease-modifying therapies have been approved for other types of spinal muscular atrophy.

According to recent research [1], the FDA has not yet approved any specific treatments for SMA-LED. However, managing symptoms and improving quality of life through physical therapy can be used to preserve range of motion and prevent further muscle wasting in affected individuals [8].

It's worth noting that the most common types of spinal muscular atrophy have disease-modifying gene therapies available, but these are not currently an option for SMA-LED. Researchers continue to explore new treatments and potential therapeutic options for this condition.

Here are some key points about SMA-LED treatment:

• No specific medications are approved for SMA-LED
• Disease-modifying therapies are available for other types of spinal muscular atrophy
• Physical therapy can help manage symptoms and improve quality of life
• Research is ongoing to explore new treatments and therapeutic options

References: [1] - [2] [8] - Managing disease symptoms and improving quality of life through physical therapy can be used to preserve range of motion and prevent further muscle wasting in affected individuals. [9] - The FDA approved nusinersen, the first drug approved to treat children (including newborns) and adults with spinal muscular atrophy (SMA), but this is not specifically for SMA-LED.

Differential Diagnosis of Spinal Muscular Atrophy with Lower Extremity Predominance (SMA-LED) 2B

Spinal muscular atrophy with lower extremity predominance (SMA-LED) is a rare genetic disorder characterized by muscle weakness and wasting in the lower limbs. The differential diagnosis for SMA-LED 2B involves identifying other conditions that may present with similar symptoms.

Conditions to Consider:

• Lower Extremity-Predominant Spinal Muscular Atrophy (SMA): This is a subtype of spinal muscular atrophy that primarily affects the lower extremities. It can be caused by mutations in the SMN1 gene and is often associated with muscle weakness, wasting, and atrophy in the lower limbs [5].
• Monomelic Amyotrophy: This is a rare condition characterized by progressive muscle weakness and wasting in one limb. It can affect any part of the body but is more commonly seen in the upper limbs. However, it can also occur in the lower extremities, making it a potential differential diagnosis for SMA-LED 2B [5].
• Spinal Muscular Atrophy with Contractures: This condition is characterized by progressive muscle weakness and wasting, often accompanied by contractures (shortening of muscles) in the affected limbs. It can be caused by mutations in the SMN1 gene and may present with symptoms similar to SMA-LED 2B [4].
• X-Linked Infantile Spinal Muscular Atrophy: This is a rare genetic disorder that affects infants and young children, characterized by progressive muscle weakness and wasting. While it primarily affects the upper limbs, it can also involve the lower extremities, making it a potential differential diagnosis for SMA-LED 2B [4].

Key Features to Consider:

• Age of Onset: The age at which symptoms first appear can be an important factor in differentiating between these conditions. SMA-LED 2B typically presents in childhood or adolescence, while monomelic amyotrophy and spinal muscular atrophy with contractures may present later in life [5].
• Muscle Weakness and Wasting: The distribution and severity of muscle weakness and wasting can also be helpful in differentiating between these conditions. SMA-LED 2B typically affects the lower extremities, while monomelic amyotrophy and spinal muscular atrophy with contractures may affect any part of the body [5].
• Contractures: The presence or absence of contractures can also be an important factor in differentiating between these conditions. Spinal muscular atrophy with contractures is characterized by progressive muscle weakness, wasting, and contractures, while SMA-LED 2B typically does not involve contractures [4].

Conclusion:

The differential diagnosis for spinal muscular atrophy with lower extremity predominance (SMA-LED) 2B involves identifying other conditions that may present with similar symptoms. Conditions such as lower extremity-predominant spinal muscular atrophy, monomelic amyotrophy, spinal muscular atrophy with contractures, and X-linked infantile spinal muscular atrophy should be considered in the differential diagnosis of SMA-LED 2B. A thorough evaluation of clinical features, age of onset, muscle weakness and wasting, and contractures can help differentiate between these conditions.