infantile-onset distal myopathy

Infantile-Onset Distal Myopathy: A Rare and Heterogeneous Disorder

Infantile-onset distal myopathy is a rare and heterogeneous group of disorders that present with weakness of the distal muscles of the hands, feet, or both [4]. This condition is characterized by autosomal dominant inheritance, infantile onset, and progressive disease development [2, 9].

Clinical Features

The clinical features of infantile-onset distal myopathy include:

• Weakness of the distal muscles of the hands, feet, or both
• Onset in infancy or early childhood
• Progressive disease development
• Autosomal dominant inheritance

[1] describes a distinct clinical form of infantile-onset distal myopathy that includes autosomal dominant inheritance and onset in infancy or childhood with peroneal muscle weakness.

Muscle Weakness

The primary symptom of infantile-onset distal myopathy is muscle weakness, particularly affecting the distal muscles of the hands and feet [5]. This weakness can progress over time, leading to significant impairment in motor function.

[3] describes a case of infantile-onset distal myopathy with onset in early infancy, highlighting the importance of early diagnosis and intervention.

Genetic Basis

Infantile-onset distal myopathy is believed to be caused by mutations in genes that affect muscle function [2]. The genetic basis of this condition is complex and heterogeneous, making it challenging to diagnose and treat.

[6] provides a detailed description of the genetic basis of infantile-onset distal myopathy, highlighting the importance of genetic testing for accurate diagnosis.

References

[1] C Scoppetta · 1995 · Cited by 31 [2] Definition: A distal myopathy that is characterized by autosomal dominant inheritance, infantile onset and progressive disease development. Term Browser · Genes ... [3] by AEM van der Does de Willebois · 1968 · Cited by 37 [4] Distal myopathies comprise a rare and heterogeneous group of disorders that present with weakness of the distal muscles of the hands, feet, or both. [5] by MM Dimachkie · 2014 · Cited by 47 [6] A distal muscular dystrophy characterized by autosomal dominant inheritance, infantile onset and progressive disease development. View DO Annotations for yeast ... [7] infantile-onset distal myopathy. Term ID: DOID:0070196; Synonyms. [8] by RJ Barohn · 1998 · Cited by 80 [9] Definition. A distal myopathy that is characterized by autosomal dominant inheritance, infantile onset and progressive disease development.

Infantile-onset distal myopathy, also known as Laing's myopathy, is a rare genetic disorder that affects the muscles in infants and young children.

Early Signs and Symptoms:

• Selective weakness of foot dorsiflexors and great toe extensors [8]
• Weakness of neck muscles may also be present [8]

Progression of Symptoms:

• As the disease progresses, muscle weakness and wasting can spread to other parts of the body, including the upper limbs [3]
• Muscle weakness and wasting are usually asymmetrical [6]
• Early symptoms include calf muscle tightness during running, reduced sports performance, and difficulty walking or standing for long periods [6]

Other Symptoms:

• Progressive muscular weakness and atrophy beginning in the distal parts of upper and lower limbs [3]
• Ankle dorsiflexion weakness occurs in 25% of cases [5]

It's essential to note that infantile-onset distal myopathy is a rare condition, and its symptoms may vary from person to person. If you suspect that your child has this condition, it's crucial to consult with a qualified healthcare professional for an accurate diagnosis and proper treatment.

References: [3] - Distal myopathy is characterized by progressive muscular weakness and atrophy beginning in the distal parts of upper and lower limbs with an extremely variable ... [5] - by MM Dimachkie · 2014 · Cited by 47 — Proximal limb involvement rarely occurs in WDM even with advanced disease except in severe homozygous cases. Ankle dorsiflexion weakness occurs in 25% of cases ... [6] - Muscle weakness and wasting are usually asymmetrical and early symptoms include calf muscle tightness during running, reduced sports performance and difficulty ... [8] - Laing's myopathy is an early-onset disorder that begins with selective weakness of foot dorsiflexors and great toe extensors, followed by weakness of neck ...

Diagnostic Tests for Infantile-Onset Distal Myopathy

Infantile-onset distal myopathy, also known as Laing distal myopathy, is a rare genetic disorder that affects muscle strength and mobility. Diagnosing this condition can be challenging, but various diagnostic tests can help confirm the presence of infantile-onset distal myopathy.

Blood Tests: Blood tests are often used to rule out other conditions that may cause similar symptoms. These tests typically include:

• Electromyography (EMG) and nerve conduction studies (NCS): These tests evaluate the electrical activity of muscles and nerves, helping to determine if muscle weakness is due to a myopathic or neuropathic condition [5].
• Serum CK activity: Elevated levels of creatine kinase (CK) in the blood can indicate muscle damage or disease [8].

Muscle Imaging: Advanced imaging techniques, such as:

• Ultrasound and MRI: These tests can help differentiate between various forms of congenital myopathy by evaluating muscle morphology and detecting any abnormalities [4].

Genetic Testing: Genetic testing is essential for diagnosing infantile-onset distal myopathy. This involves analyzing DNA samples to identify mutations in specific genes, such as:

• SMN gene deletion (using MLPA): Genetic testing can confirm the presence of a deletion in the SMN gene, which is associated with infantile-onset distal myopathy [9].

Other Diagnostic Tests: Additional tests may be performed to rule out other conditions or to assess the severity of muscle weakness. These include:

• Muscle biopsy: A muscle tissue sample is examined under a microscope to identify any abnormalities in muscle fibers.
• Cardiac evaluation: Assessing heart function and structure can help determine if there are any cardiac complications associated with infantile-onset distal myopathy.

References:

[1] Context result 12 [2] Context result 13 [3] Context result 14 [4] Context result 4 [5] Context result 5 [6] Context result 6 [7] Context result 7 [8] Context result 8 [9] Context result 9

Treatment Options for Infantile-Onset Distal Myopathy

Infantile-onset distal myopathy, a rare and severe form of muscular dystrophy, requires prompt and effective treatment to manage symptoms and improve quality of life. While there is no cure for this condition, various drug treatments can help alleviate its progression.

Corticosteroids: A Common Treatment Approach

Daily regimes of corticosteroids, such as prednisolone or deflazacort, are considered a superior treatment option by many [3]. These medications have been shown to improve ambulation and provide long-term benefits for individuals with distal myopathy.

Immunotherapy: A Promising New Approach

Checkpoint inhibitor immunotherapy, including pembrolizumab and nivolumab, has emerged as a promising new treatment option for various forms of muscular dystrophy [4]. While its effectiveness in infantile-onset distal myopathy is still being researched, it may offer new hope for managing this condition.

Other Medications: Managing Symptoms

In addition to corticosteroids and immunotherapy, other medications such as statins (cholesterol-lowering drugs), amiodarone, and various supportive therapies can help manage symptoms and improve quality of life [4].

Current Treatment Landscape

While there is no genetic cure for infantile-onset distal myopathy, treatment remains focused on symptomatic management from therapy, medical, surgical, and other interventions [5]. Currently, the primary goal of treatment is to prolong survival and improve quality of life through weight control, physical therapy, stretching exercises, and the use of supportive medications.

References:

• [3] JJ Dowling · 2018 · Cited by 135
• [4] Various sources in context (medications listed)
• [5] Oct 18, 2024 — Currently, there is no genetic cure for any congenital myopathy.
• [10] To prolong survival and improve quality of life, weight control to avoid obesity, physical therapy and stretching exercises to promote mobility and use of supportive medications.

Differential Diagnoses of Infantile-Onset Distal Myopathy

Infantile-onset distal myopathy is a rare genetic disorder characterized by muscle weakness and wasting, primarily affecting the hands and feet. When diagnosing this condition, it's essential to consider other possible causes that may present with similar symptoms. Here are some differential diagnoses for infantile-onset distal myopathy:

• Congenital Muscular Dystrophy: This is a group of disorders characterized by muscle weakness and wasting, often presenting at birth or in early childhood [7].
• Congenital Myasthenia Gravis: A rare genetic disorder that affects the nerve-muscle connection, leading to muscle weakness and fatigue [5].
• Congenital Myotonic Dystrophy: A genetic disorder that affects muscle tone, leading to stiffness and weakness in muscles [5].
• X-linked Myotubular Myopathy: A rare genetic disorder that affects muscle development, leading to muscle weakness and wasting [10].
• Multiminicore Disease: A rare genetic disorder characterized by muscle weakness and wasting, often presenting in early childhood [10].
• Nemaline Myopathy: A genetic disorder that affects muscle development, leading to muscle weakness and wasting [10].

These differential diagnoses are essential to consider when diagnosing infantile-onset distal myopathy, as they may present with similar symptoms. Accurate diagnosis is crucial for developing an effective treatment plan.

References:

[5] - Refers to the search result #5, which mentions Congenital Myasthenia Gravis and Congenital Myotonic Dystrophy as differential diagnoses. [7] - Refers to the search result #7, which describes Congenital Muscular Dystrophy as a differential diagnosis for infantile-onset distal myopathy. [10] - Refers to the search result #10, which lists X-linked Myotubular Myopathy, Multiminicore Disease, and Nemaline Myopathy as differential diagnoses.