About batten turner congenital myopathy

What is batten turner congenital myopathy?

Batten Turner Type Congenital Myopathy is an extremely rare, inherited muscle disease (myopathy) and is characterized by the lack of muscle tone or floppiness at birth (congenital hypotonia). The symptoms of Batten Turner Type Congenital Myopathy are slowly progressive during infancy and childhood. However, this disorder is not progressive in adulthood.

What are the symptoms for batten turner congenital myopathy?

The subtypes of CM have highly variable severity of muscle loss symptoms and differ in the age of onset.

General symptoms of congenital myopathy in a newborn are the slow, progressive loss of muscle tone characterized by floppiness (hypotonia) and general weakness. Early motor skills and other critical developmental milestones may be delayed. Toddlers with this disorder usually have mild Muscle Weakness and may be prone to falling or stumbling. The muscles of the pelvis, neck, and shoulder area are most commonly affected. Since the symptoms of this disease are not progressive during adulthood, most people with congenital myopathy walk normally as adults. However, some physical activities may be slightly impaired.

Typically, diagnosis of CM subtypes requires the use of muscle biopsy and looking at the structural make-up of the muscles under a microscope. Symptoms seen in one subtype are generally seen in other subtypes with slight exceptions and nuances.

Nemaline myopathy (NM) is also known as rod myopathy. NM is characterized by abnormal rod- or thread-like structures present in muscle fibers under a microscope. These abnormal rod structures are associated with problems in the contraction and tone of affected skeletal muscles, ultimately leading to muscle weakness.

There are six different types of NM which are based on age and severity: severe congenital, Amish, intermediate congenital, typical congenital, childhood-onset, and adult-onset. Severe cases of NM are typically seen in young children, while milder versions of NM are seen in adulthood. Muscle Weakness is caused by decreased muscle tone in NM which generally occurs throughout the body and is most severe in the neck, face, and skin muscles. One symptom of NM includes bulbar Muscle Weakness indicated by difficulty speaking (dysarthria), Difficulty swallowing (dysphagia), and excess saliva production (sialorrhea). In infants, bulbar Muscle Weakness is mainly presented as Difficulty feeding while older children and adults exhibit difficulty swallowing. Other symptoms include foot deformities, curvature of the spine (scoliosis), as well as Joint deformities (contractures). 

Core myopathies are characterized by areas in the muscle fiber that lack oxidative enzymatic activity. There are two types of muscle fiber core myopathy: central core disease (CCD) and multiminicore disease (MmD). CCD is characterized by the presence of single, well-circumscribed circular regions in the middle of type 1 fibers of the muscle that do not contain mitochondria. CCD is more common in infants who have Hypotonia or seen in children with delays in motor development. CCD mainly affects the proximal and axial muscles. Orthopedic and Joint deformities seen in nemaline myopathy are not seen in these patients. Eye muscles are not affected in this type of congenital myopathy. Pathologically, CCD can be observed in the tissue fibers by staining sections of the muscle fiber for oxidative enzyme activity. Patients with MmD also exhibit similar severity of symptoms compared to CCD with the exception of axial muscle weakness, especially in the head and neck muscle, which is much more severe in MmD. 

Centronuclear myopathy (CNM) is characterized by the abundant amount of centralized nuclei in muscle fibers when viewed in the microscope. One type of CNM, XLMTM, affects newborn boys and is generally clinical severe. Symptoms of XLMTM include an excess of amniotic fluid (polyhydramnios) and reduced fetal movements during pregnancy, thin ribs, weak eye muscles (ophthalmoplegia), drooping upper eyelid (ptosis), pyloric stenosis, knee, and hip contractures, and muscle wasting. Other forms of CNM can affect either males or females and tend to show more mild clinical signs. 

Congenital fiber-type disproportion (CFTD) occurs when an abundant amount of type I (slow twitch) muscle fibers are 35-40% smaller than type II (fast twitch) muscle fibers. Many symptoms from the previous three myopathy types can be seen in CFTD as well. Additional symptoms include respiratory failure and nocturnal hypoventilation. 

What are the causes for batten turner congenital myopathy?

There is still emerging research on the causes of CM and mutations in more than twenty genes have been associated with CM. Genes responsible for calcium ion balance in muscle cells have been implicated in some inherited forms of the disease. Calcium ion balance is important in muscle cells because calcium is a signal for muscle cells to contract. Other mutations described in CM patients occur in genes that lead to malformed filaments in muscle cells. These filaments are normally responsible for the contraction of muscles.

Most types of CM follow an autosomal recessive pattern of inheritance. Recessive genetic disorders occur when an individual inherits a non-working gene from each parent. If an individual receives one working gene and one non-working gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms. The risk for two carrier parents to both pass the non-working gene and, therefore, have an affected child is 25% with each pregnancy. The risk to have a child who is a carrier, like the parents, is 50% with each pregnancy. The chance for a child to receive working genes from both parents is 25%. The risk is the same for males and females.

Structural defects such as rods or protein accumulation are common in nemaline myopathies, core-rod myopathy, and other types of CM are associated with mutations in genes such as ACTA1, CFL2, KBTBD13, KLHL40, KLHL41, LMOD3, NEB, RYR1, TNNT1, TPM2, and TPM3. The most common cause of nemaline myopathies is autosomal recessive mutations in the NEB gene which accounts for up to 50% of cases, followed by ACTA1 (~25%).

Structural defects in cores seen in central core and multiminicore disease have been shown to be associated with mutations in the RYR1, MEGF10, MYH7, and SEPN1 genes. An overwhelming majority of patients with CCD (>90%) have a RYR1 mutation. Those with two RYR1 mutations have a more severe presentation than patients with a single RYR1 mutation or mutations in other genes. Most MmD is caused by recessive mutations in the SEPN1 gene.

Structural defects in central nuclei of centronuclear myopathy are associated with mutations in genes such as BIN1, CCDC78, DNM2, MTM1, RYR1, SPEG, and TTN.

X-linked myotubular myopathy is the most common and severe type with prenatal or neonatal onset. Autosomal recessive forms have a typical onset in infancy or childhood and autosomal dominant forms have the mildest symptoms and may present in adulthood. Most patients with centronuclear myopathy have mutations in the MTM1 gene which leads to X-linked myotubular myopathy, a type of CNM. DNM2 gene mutations are the second most common cause and result in milder symptoms. Mutations in the RYR1, TTN, and BIN1 genes have been identified in recessive forms and have highly variable symptom presentation.

Structural defects that lead to fiber size variation are commonly seen in congenital fiber-type disproportion CM and have been shown to involve genes including ACTA1, MYH7, RYR1, SEPN1, TPM2, and TPM3. Most CFTD CM are associated with mutations in the TPM3 gene and some patients have been identified with ACTA1, MYH1, SEPN1, and TPM2 mutations. Mutation in the LMNA gene have been found in several Japanese patients and could be related to a subset of CFTD CM patients at risk for cardiac disease.

Known genes have been found in 50-70% of families with CM, so other genetic causes remain to be identified.

What are the treatments for batten turner congenital myopathy?

Adults with congenital myopathy should be encouraged to get adequate exercise and to avoid unhealthy dietary and sedentary habits that may lead to obesity. Affected adults may experience episodes of mild muscle weakness, but generally there are no major physical disabilities.

Medications, nutritional and respiratory support, orthopedic support, physical, occupational, or speech therapy may also be necessary to recover quality of life in affected patients.

Genetic counseling is recommended for affected families.

What are the risk factors for batten turner congenital myopathy?

Batten turner congenital myopathy is a rare genetic disorder that is passed down through families. The exact cause of the condition is unknown, but it is thought to be associated with problems in the genes that control muscle development and function.
There are a number of risk factors that have been identified as being associated with batten turner congenital myopathy. These include:
1. Having a family history of the condition – this means that if you have a parent or sibling with the condition, you are more likely to develop it yourself.
2. Being of Ashkenazi Jewish descent – this ethnic group has a higher risk of developing batten-turner congenital myopathy.
3. Being female – females are more likely to develop the condition than males.
4. Certain genetic mutations or abnormalities
5. Exposure to certain environmental toxins
6. Prenatal exposure to certain medications or infections
7. If you have any of these risk factors, it is important to speak to your doctor so that they can monitor your health closely. There is no cure for batten turner congenital myopathy, but early diagnosis and treatment can help to improve the symptoms and quality of life for those affected by the condition.

Muscle weakness,Difficulty breathing,Cardiac problems including arrhythmias (irregular heartbeat),Gastrointestinal issues
Dilated cardiomyopathy,Gastrointestinal issues,Respiratory insufficiency,Muscle atrophy,Joint contractures
No specific drugs are used to treat batten turner congenital myopathy, but symptomatic treatments may be prescribed

Is there a cure/medications for batten turner congenital myopathy?

Batten turner congenital myopathy involves progressive muscle degeneration.

1. There is not currently a cure for batten turner congenital myopathy; however, there are treatments available that can help manage the symptoms of the condition.
2. There is no specific medication that is used to treat this condition, but various medications may be prescribed to help with symptoms such as muscle weakness, pain, and seizures.
3. Medications such as Anticytokine therapy and Spinraza (nusinersen) can help improve the quality of life for those with Batten Turner Congenital Myopathy. However, these will be required for patients presenting with only certain conditions, such as cognitive decline.
4. Physical therapy and other forms of rehabilitation can also be helpful in managing the symptoms of this condition. Physical therapy and other forms of rehabilitation can also help keep muscles strong and healthy for as long as possible.
5. In some cases, surgical procedures may be necessary to help improve the quality of life.
6. Clinical trials are ongoing in an attempt to find new and effective treatments for this condition.
7. If you or your child has been diagnosed with this condition, speak to your doctor about the best course of treatment.

Muscle weakness,Difficulty breathing,Cardiac problems including arrhythmias (irregular heartbeat),Gastrointestinal issues
Dilated cardiomyopathy,Gastrointestinal issues,Respiratory insufficiency,Muscle atrophy,Joint contractures
No specific drugs are used to treat batten turner congenital myopathy, but symptomatic treatments may be prescribed

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