obsolete distal hereditary motor neuronopathy type 5A

Distal Hereditary Motor Neuronopathy Type 5A (DHMN5A) was a rare genetic disorder characterized by the progressive degeneration of motor neurons in the peripheral nervous system. This condition primarily affected the distal muscles, leading to weakness and wasting predominantly in the hands and feet.

The DHMN5A was caused by a heterozygous mutation in the GARS gene on chromosome 7p14.3 or the BSCL2 gene on chromosome 11q12.3 [1][4]. This genetic alteration led to the degeneration of motor neurons, resulting in muscle weakness and atrophy.

The symptoms of DHMN5A typically began in young adulthood and progressed slowly over time. The condition was inherited in an autosomal dominant pattern, meaning that a single copy of the mutated gene was sufficient to cause the disorder [2][7].

Deep tendon reflexes were often preserved or only mildly affected in patients with DHMN5A [9]. However, muscle weakness and atrophy gradually worsened over time, affecting the distal muscles more severely than the proximal ones.

Unfortunately, there is limited information available on the treatment and management of DHMN5A. As a result, this condition was often considered incurable, and patients were typically managed symptomatically to alleviate their symptoms [8].

The DHMN5A has been merged with other conditions in modern medical classification systems, such as distal hereditary motor neuronopathy type 5 (DHMN5) [10]. This merger reflects the current understanding of the genetic basis of this condition and its relationship to other similar disorders.

References:

[1] Definition: A distal hereditary motor neuronopathy type 5 that has_material_basis_in heterozygous mutation in GARS on 7p14.3 or BSCL2 on 11q12.3. [2] An autosomal dominant distal hereditary motor neuronopathy that is characterized by onset of distal muscle weakness and atrophy predominantly affecting the ... [4] Description. Remap. Code: 1197152005. Descriptor: Distal hereditary motor neuropathy type 5 (disorder). Code System: SNOMEDCT. Code System Version: 2024-03. [7] A rare autosomal dominant distal hereditary motor neuropathy disease characterized by muscle weakness and wasting predominantly affecting the hands, ... [9] by S Rudnik-Schöneborn

Distal Hereditary Motor Neuropathy Type 5A (DHMN VA) Signs and Symptoms

Distal Hereditary Motor Neuropathy Type 5A, also known as DHMN VA, is a rare autosomal dominant disorder characterized by progressive muscle weakness and atrophy. The symptoms of this condition can vary in severity and onset, but here are some common signs and symptoms:

• Muscle Weakness: Muscle weakness is the primary symptom of DHMN VA, affecting both upper and lower limbs. This weakness can progress to muscle atrophy over time.
• Distal Muscle Atrophy: The muscles in the hands and feet are often affected first, leading to wasting and atrophy of these muscles.
• Foot Deformity: Foot deformities, such as pes cavus (high arches), are a common feature of DHMN VA.
• Gait Disturbance: As the condition progresses, patients may experience difficulty walking due to muscle weakness and atrophy in the lower limbs.
• Pyramidal Signs: Some patients may exhibit pyramidal signs, such as spasticity and hyperreflexia, particularly in the lower limbs.
• Cramps and Weakness: Cramps or weakness in the muscles of the big toe are often an initial symptom of DHMN VA.

Age of Onset

The age of onset for DHMN VA can vary significantly, ranging from infancy to the mid-thirties. Symptoms usually begin during adolescence, but some patients may experience symptoms earlier or later

Diagnostic Tests for Distal Hereditary Motor Neuropathy Type 5A

Distal hereditary motor neuropathy type 5A (dHMN5A) is a rare neuromuscular disorder characterized by progressive muscle weakness and wasting, predominantly affecting the upper limbs. Diagnostic tests play a crucial role in confirming the diagnosis of this condition.

Electromyography (EMG)

• EMG testing reveals reduced motor amplitude potentials with no sensory abnormalities [9].
• This test can help identify the presence of pure motor neuropathy patterns without upper motor neuron damage in the hands [6].

Clinical Genetic Test

• The Invitae Hereditary Motor Neuropathy Panel analyzes genes associated with hereditary motor neuropathies, including dHMN5A [3].
• Clinical genetic tests, such as sequence analysis of the entire coding region and next-generation sequencing (NGS), are available for diagnosing dHMN5A [12].

Other Diagnostic Tests

• Electrophysiology testing may reveal reduced motor amplitude potentials with no sensory abnormalities [9].
• Neurophysiology testing can also show patterns of weakness without upper motor neuron damage in the hands [6].

Genetic Testing Information

• Genetic testing for dHMN5A involves analyzing genes such as BSCL2 (11q12.3) and GARS1 [4, 15].
• The Genetic Testing Registry provides information on genetic tests available for diagnosing dHMN5A [15].

It's essential to note that a comprehensive diagnostic evaluation by a multidisciplinary team, including genetics, neurology, and electromyography, is necessary for accurate diagnosis and management of distal hereditary motor neuropathy type 5A.

References: [3] The Invitae Hereditary Motor Neuropathy Panel [4] Clinical Genetic Test offered by Intergen [6] Diagnosis in an individual with dHMN V [9] Neurophysiology testing reveals reduced motor amplitude potentials with no sensory abnormalities [12] Clinical Molecular Genetics test for Neuronopathy, distal hereditary motor, type 5A [15] Genetic Testing Information • Genetic Testing Registry: Neuronopathy, distal hereditary motor, type 5

Based on the provided context, it appears that there are some outdated information available regarding the treatment of distal hereditary motor neuronopathy type 5A (dHMN5A).

According to search result [9], as of February 2024, there is currently no cure for dHMN5A, and doctors help people manage their symptoms instead. Generally, physical therapy and occupational therapy are recommended.

However, it's worth noting that some older information suggests that liver-directed gene therapy; hepatocyte transfer may be a favorable treatment option if the patient is compliant with medical treatment [8].

It's also mentioned in search result [10] that there are available genetic tests from US labs around the world for GARS1 and other related genes, which can provide more information about the condition.

Regarding drug treatments, it seems that there is limited information available. However, some older studies suggest that tafamidis, patisiran, inotersen, and diflunisal may show significant benefit in high-quality evidence [6].

It's essential to consult with a healthcare professional for medical advice and treatment, as they can provide the most up-to-date and accurate information regarding the management of dHMN5A.

Current Treatment Options:

• Physical therapy
• Occupational therapy

Outdated or Experimental Treatments: * Liver-directed gene therapy; hepatocyte transfer (may be favorable if patient compliant with medical treatment) * Tafamidis, patisiran, inotersen, and diflunisal (older studies suggest significant benefit)

Please consult a healthcare professional for the most accurate and up-to-date information regarding the treatment of dHMN5A.

The differential diagnosis of distal hereditary motor neuronopathy type 5A (dHMN5A) involves distinguishing it from other neuromuscular disorders that present with similar symptoms. According to the available information, dHMN5A can be differentiated from:

• Juvenile forms of amyotrophic lateral sclerosis (ALS), which could also be caused by variations in the GARS1 gene [2][3]
• Hereditary spastic paraplegia, another neuromuscular disorder that affects motor function [3]

It's worth noting that muscle MRI and muscle ultrasound can be used to detect fasciculations and guide the differential diagnosis between distal myopathies and neuronopathies [1]. Additionally, elevated creatine kinase (CK) levels can also be a useful diagnostic marker.

In terms of genetic testing, mutations in the GARS1 gene are associated with dHMN5A, but other genes such as HSPB1, BICD2, and DNAJB2 may also be involved in distal hereditary motor neuropathies [10].

References:

[1] Context result 2 [2] Context result 3 [3] Context result 8 [10] Context result 10