autosomal recessive distal hereditary motor neuronopathy 3

Autosomal Recessive Distal Hereditary Motor Neuronopathy 3 (HMNR3), also known as Distal Spinal Muscular Atrophy (DSMA) and Distal Hereditary Motor Neuropathy (dHMN or HMN), is a rare genetic disorder characterized by distal muscle weakness and wasting without significant sensory involvement.

Key Features:

• Distal Muscle Weakness: The condition primarily affects the muscles in the distal parts of the limbs, such as the hands and feet.
• Muscle Wasting: As the disease progresses, there is a noticeable wasting of the affected muscles.
• No Sensory Involvement: Unlike other forms of hereditary motor neuropathies, HMNR3 does not involve significant sensory abnormalities.

Other Important Points:

• The condition typically begins in childhood or adolescence and can be inherited in an autosomal recessive pattern.
• There is a genetic heterogeneity of autosomal recessive HMN, with multiple genes contributing to the disease (see HMNR1 for more information).
• The clinical features of HMNR3 are similar to those of other forms of distal hereditary motor neuropathies.

References:

• [2] Autosomal recessive distal hereditary motor neuronopathy-3 (HMNR3) is characterized by distal muscle weakness and wasting without significant sensory involvement.
• [4] This article summarizes the clinical, electrophysiological and genetic aspects of distal hereditary motor neuropathies (dHMN), a group of rare inherited disorders of spinal motor neurons.

Autosomal recessive distal hereditary motor neuronopathy 3 (dHMN III) is a rare genetic disorder characterized by progressive muscle weakness and wasting, primarily affecting the hands. The clinical features of dHMN III include:

• Distal muscle weakness: Weakness in the muscles of the hands, feet, and lower legs, which can lead to difficulties with fine motor tasks such as writing or buttoning shirts.
• Muscle wasting: Atrophy of the affected muscles, particularly noticeable in the hands and feet.
• Pes cavus foot deformity: A condition where the arch of the foot is abnormally high, leading to a "high-arched" appearance.
• Diminished deep tendon reflexes: Reduced or absent reflexes in the affected limbs.

These symptoms typically become apparent during childhood or adolescence. In some cases, individuals with dHMN III may also experience additional features such as vocal cord paralysis or diaphragm paralysis, although these are less common [9].

It's essential to note that intellectual development and cognitive function are generally unaffected in individuals with dHMN III, and brain imaging is typically normal [8]. However, the progressive nature of this disorder can lead to significant disability and impact daily life.

References: [1] - Not applicable (this information was not present in the search results) [2] - Not applicable [3] - Not applicable [4] - Not applicable [5] - Not applicable [6] - Not applicable [7] - Not applicable [8] Oct 23, 2023 — Foot deformities and calf atrophy are commonly observed. Intellectual development, cognitive function, and brain imaging are typically normal. [9] by J Irobi · 2004 · Cited by 114 — Often, unusual or additional features are present in 'complicated' distal HMN, including predominance in the hands, vocal cord paralysis, diaphragm paralysis ...

Autosomal recessive distal hereditary motor neuronopathy 3 (HMNR3), also known as distal spinal muscular atrophy (DSMA) and distal hereditary motor neuronopathy (dHMN or HMN), is a neuromuscular disorder characterized by progressive muscle weakness and wasting, predominantly affecting the distal parts of limbs.

Diagnostic Tests:

• Neurophysiology testing: This test reveals reduced motor amplitude potentials with no sensory abnormalities. It can help confirm the diagnosis of HMNR3.
• Electromyography (EMG) testing: EMG may reveal a predominantly distal pattern of muscle denervation, which is consistent with HMNR3.
• Nerve conduction studies: These studies can show reduced nerve conduction velocities and amplitudes in affected nerves.
• Genetic testing: Genetic testing can be used to diagnose specific inherited peripheral neuropathies, including HMNR3. This test can identify mutations in the HSPB1 gene, which is a common cause of distal hereditary motor neuropathies.

Additional Tests:

• Exome Sequencing with CNV Detection: This test can also be used to identify genetic mutations associated with HMNR3.
• Imaging studies: While not typically used for diagnosis, imaging studies such as MRI or CT scans may show muscle atrophy and weakness in affected individuals.

It's worth noting that a combination of clinical presentation, family history, and laboratory tests is often necessary to confirm the diagnosis of HMNR3. A healthcare professional should be consulted for proper evaluation and diagnosis.

References:

• [2] Autosomal recessive distal hereditary motor neuronopathy-3 (HMNR3) is characterized by distal muscle weakness and wasting without significant sensory involvement.
• [4] In addition to clinical presentation, nerve conduction studies, and family history, genetic testing can be used to diagnose specific inherited peripheral neuropathies.
• [6] Test Method: Exome Sequencing with CNV Detection. New York State Approved Test.
• [12] The distal hereditary motor neuropathies (dHMN) comprise a heterogeneous group of diseases that share the common feature of a length-dependent predominantly motor neuropathy.

Based on the provided context, it appears that there are some treatment options available for autosomal recessive distal hereditary motor neuronopathy 3 (HMNR3), also known as distal spinal muscular atrophy (DSMA) and distal hereditary motor neuronopathy (dHMN or HMN).

• Newly available targeted treatment options: According to search result [10], newly available targeted treatment options are changing the management of HMNR3. However, no specific details about these treatments are provided.
• Treatment with DTHBQ rescued 3/5 worms: In search result [2], it is mentioned that treatment with DTHBQ rescued 3/5 RTN2 deficient worms in phenospace with respect to the top principal components in the behavioral feature set upon drug treatment. However, this information seems to be related to a specific study and may not directly translate to human treatment.
• Lipid nanoparticle delivered antisense oligonucleotides: In search result [14], it is mentioned that lipid nanoparticle delivered antisense oligonucleotides are being explored as a therapeutic approach for hereditary neuropathy, including CMT1A. However, no specific information about the use of this treatment in HMNR3 is provided.

It's essential to note that these findings suggest that there may be some emerging treatment options available for HMNR3, but more research and clinical trials are needed to confirm their efficacy and safety in humans.

References: [2], [10], [14]

The differential diagnosis for autosomal recessive distal hereditary motor neuronopathy (HMNR) involves distinguishing it from other neuromuscular disorders that present with similar symptoms.

According to the available information, one of the key conditions to consider in the differential diagnosis is juvenile forms of amyotrophic lateral sclerosis (ALS). This is because variations in certain genes can cause both HMNR and ALS, making them difficult to distinguish based solely on clinical presentation [5].

Other conditions that may be considered in the differential diagnosis include:

• Distal hereditary motor neuropathies caused by mutations in other genes, such as HSPB1, GARS1, BICD2, and DNAJB2 [7]
• Other forms of neuromuscular disorders that present with muscle weakness and diaphragmatic palsy

It's worth noting that the differential diagnosis for HMNR can be complex and may require a comprehensive evaluation by a qualified healthcare professional.