congenital myopathy 17

Congenital Myopathy 17 (CMYO17) Overview

Congenital myopathy 17, also known as CMYO17, is a rare autosomal recessive muscle disorder that affects individuals from birth. The condition is characterized by:

• Hypotonia: Affected individuals are born with low muscle tone, which can lead to weakness and fatigue.
• Respiratory insufficiency: Individuals with CMYO17 often experience breathing difficulties soon after birth.

Additional features of CMYO17 may include high diaphragmatic dome on chest X-rays, indicating a possible connection between the lungs and the diaphragm. The condition is caused by an autosomal recessive mutation in the gene responsible for myotilin (titin immunoglobulin domain protein; TTID), which also causes other muscle disorders.

Key Points

• Autosomal recessive inheritance pattern
• Hypotonia and respiratory insufficiency present at birth
• High diaphragmatic dome on chest X-rays may be associated with the condition
• Caused by a mutation in the myotilin gene (TTID)

References: 1. [Description ... Congenital myopathy-17 is an autosomal recessive muscle disorder.] 2. [An autosomal recessive muscular disorder characterized by hypotonia and respiratory insufficiency apparent soon after birth, high diaphragmatic dome on ...] 3. [Congenital myopathy 17 is an autosomal recessive muscle disorder characterized by hypotonia and respiratory insufficiency at birth.] 4. [Description. Congenital myopathy-17 (CMYO17) is an autosomal recessive muscle disorder. Affected individuals present at birth with hypotonia and respiratory ...] 5. [Congenital myopathy-17 (CMYO17) is an autosomal recessive muscle disorder. Affected individuals present at birth with hypotonia and respiratory ...]

Based on the provided context, here are the signs and symptoms of congenital myopathy:

• Muscle weakness: Congenital myopathies can cause severe, general muscle weakness that complicates basic activities like swallowing and breathing [2].
• Floppiness: Symptoms include face, arm, and leg weakness along with breathing difficulties [1].
• Breathing difficulties: Hard time breathing is a common symptom of congenital myopathy [3].
• Eating difficulties: Hard time eating due to muscle weakness [3].
• Delayed motor skills: Slow to reach developmental goals; Delayed motor (movement) skills [3].
• Scoliosis: Common to most congenital myopathies is severe weakness of the limbs and scoliosis [7].
• Weakened eye movements: Some children have weakened eye movements [7].
• Muscle cramps, stiffness, and spasm: Other symptoms of myopathy can include muscle cramps, stiffness, and spasm [8].
• Symmetric muscle weakness: Most myopathies share the common symptom of symmetric muscle weakness (similar on both sides of your body), especially in proximal muscles [9].

Please note that these symptoms may vary depending on the specific type of congenital myopathy. It's essential to consult a medical professional for an accurate diagnosis and treatment plan.

Diagnostic Tests for Congenital Myopathies

Congenital myopathies are a group of rare muscle disorders that can be diagnosed through various diagnostic tests. Here are some of the common tests used to diagnose congenital myopathies:

• Muscle Biopsy: This is a surgical procedure where a small sample of muscle tissue is removed and examined under a microscope for signs of muscle damage or abnormality [4][7]. Muscle biopsy is considered the gold standard for diagnosing congenital myopathies.
• Serum Creatine Kinase (CK) Test: Elevated levels of serum CK can indicate muscle damage, which may be suggestive of a congenital myopathy [1][3].
• Nerve Conduction Study (NCS): This test measures the electrical activity of nerves and muscles. Abnormal results from NCS can help confirm the diagnosis of a congenital myopathy [2][6].
• Electromyography (EMG): EMG is a test that records the electrical activity of muscles. It can help identify abnormal muscle activity, which may be indicative of a congenital myopathy [2][6].
• Muscle Imaging: This includes tests such as MRI or CT scans to visualize the muscle tissue and look for any abnormalities [6].

It's worth noting that while these diagnostic tests can help confirm the diagnosis of a congenital myopathy, they are not always specific for this condition. A correct diagnostic approach requires the integration of data from multiple sources, including clinical evaluations, family history, and other investigations [4].

Current State of Drug Treatment for Congenital Myopathies

There are currently very limited therapeutic options that effectively target congenital myopathies, a group of rare genetic disorders affecting muscle function [2]. Most available drugs are largely symptom-alleviating agents, and there is an urgent need for more effective treatments.

Pharmacological compounds used in several types of congenital myopathies target the neuromuscular junction (NMJ) and mTOR pathways [1][3]. These consist in correcting or improving the underlying genetic defects mainly using genetic-based approaches, and normalizing the disease [5].

Emerging Therapies

• Gene replacement therapy for Duchenne muscular dystrophy is currently being studied in phase 3 clinical trials, which may be available in the near future [6].
• Adeno-associated virus (AAV)-based gene therapies are also being explored as potential treatments for congenital myopathies [8].

Current Treatment Options

While there is no cure available, supportive treatment and pharmacological remission are the mainstay of treatment. Management of the condition includes physiotherapy, and other supportive measures to improve quality of life [9].

Future Directions

Advances in genetic research and gene therapy hold promise for developing more effective treatments for congenital myopathies. Ongoing clinical trials and research studies aim to identify new therapeutic targets and strategies for managing these conditions.

References:

[1] by C Gineste · 2023 · Cited by 21 — Pharmacological compounds used in several types of congenital myopathies target the NMJ (AchEI and agonist of β2R) and mTOR pathways (myostatin inhibitor).

[2] by X Guan · 2016 · Cited by 14 — There are currently very limited therapeutic options that effectively target congenital myopathies. Most available drugs are largely symptom-alleviating agents ...

[3] by C Gineste · 2023 · Cited by 21 — Pharmacological compounds used in several types of congenital myopathies target the NMJ (AchEI and agonist of β2R) and mTOR pathways (myostatin inhibitor).

[5] by C Gineste · 2023 · Cited by 21 — These consist in correcting or improving the underlying genetic defects mainly using genetic-based approaches, and normalizing the disease.

[6] by AR Findlay · 2022 · Cited by 5 — DMD gene replacement for Duchenne muscular dystrophy is currently being studied in phase 3 clinical trials, and may be available in the near future. Several ...

[8] by H Zhang · 2024 — Currently, supportive treatment and pharmacological remission are the mainstay of treatment, with no cure available. Some adeno-associated ...

Differential Diagnoses of Congenital Myopathy 17 (CMYO17)

Congenital myopathy-17 (CMYO17) is a rare, autosomal recessive muscle disorder that presents at birth with hypotonia. When diagnosing CMYO17, it's essential to consider other differential diagnoses that may present with similar symptoms.

Key Differential Diagnoses:

• Spinal Muscular Atrophy (SMA): While SMA can cause hypotonia and weakness, the presence of elevated CK levels and leukodystrophy in CMYO17 patients makes this diagnosis less likely [5].
• Congenital Myopathies: These are a group of rare, inherited primary muscle disorders that can cause gross motor delay, poor coordination, and muscle weakness. However, the specific presentation of CMYO17 with hypotonia at birth may help differentiate it from other congenital myopathies [6][7].
• Congenital Muscular Dystrophies: These are a group of rare genetic disorders that can cause muscle weakness and wasting. While they share some similarities with CMYO17, the presence of specific mutations in COL6, LAMA2, or LMNA genes makes them distinct differential diagnoses [1][10].
• Prader-Willi Syndrome: This is a genetic disorder that can cause hypotonia, poor coordination, and muscle weakness. However, the presence of specific genetic markers and clinical features may help differentiate it from CMYO17 [3].

Diagnostic Considerations:

When diagnosing CMYO17, clinicians should consider the following diagnostic criteria:

• Pattern of Weakness: A pattern of weak muscles that is most prominent in the face, shoulders, or upper arms [8].
• Genetic Testing: Genetic testing for mutations in COL6, LAMA2, LMNA, and other genes associated with congenital muscular dystrophies may help confirm the diagnosis.
• Clinical Features: The presence of specific clinical features such as hypotonia at birth, poor coordination, and muscle weakness should be carefully evaluated.

References:

[1] Oct 18, 2024 — Differential Diagnoses · Central Causes of Hypotonia · Congenital Muscular Dystrophy · Congenital Myasthenia Gravis · Congenital Myotonic Dystrophy. [3] by KN North · 2014 · Cited by 338 — The most important differential diagnoses are Prader–Willi syndrome, CMS, DM1 and severe SMA (type 0). [5] by ST Iannaccone · 2013 · Cited by 38 — The differential diagnosis included spinal muscular atrophy and congenital myopathies. [6] Aug 7, 2020 — Congenital myopathy-17 (CMYO17) is an autosomal recessive muscle disorder. Affected individuals present at birth with hypotonia and ... [7] by JK Mah · 2016 · Cited by 32 — The differential diagnoses of hypoto- nia and severe generalized weakness in the newborn or early infancy period include congenital myopathies, congeni- tal ... [8] Diagnosing Congenital Myopathies. CMs are usually diagnosed based on: A pattern of weak muscles that is most prominent in the face, shoulders or upper arms, and ... [10] by KG Claeys · 2020 · Cited by 77 — The most important differential diagnoses of congenital myopathies are congenital muscular dystrophies, congenital myotonic dystrophy type 1, ...