autosomal dominant distal hereditary motor neuronopathy 13

Autosomal dominant distal hereditary motor neuronopathy-13 (HMND13) is a neurologic disorder characterized by distal muscle weakness and atrophy affecting both the upper and lower limbs, resulting in difficulty walking and poor fine hand motor skills. Some patients show spasticity and hyperreflexia, mainly of the lower limbs: these features overlap with those observed in Silver syndrome, an autosomal dominant distal hereditary motor neuronopathy that is caused by heterozygous mutation in the BSCL2 gene on chromosome 11q12.

The symptoms of HMND13 typically begin in childhood or adolescence and progress slowly over time. The disorder affects both the upper and lower limbs, with muscle weakness and atrophy being more pronounced in the distal muscles (those farthest from the center of the body). This can lead to difficulties with walking, balance, and fine motor skills, such as writing or using small objects.

It's worth noting that HMND13 is a rare disorder, and there may be limited information available on its specific characteristics. However, it is generally considered to be part of a larger group of neuromuscular disorders known as distal hereditary motor neuropathies (dHMNs), which are characterized by slowly progressive degeneration of the anterior horn cells in the spinal cord.

Key features:

• Distal muscle weakness and atrophy affecting both upper and lower limbs
• Difficulty walking and poor fine hand motor skills
• Spasticity and hyperreflexia, mainly of the lower limbs (in some patients)
• Slowly progressive degeneration of anterior horn cells in the spinal cord

References:

• [1] Autosomal dominant distal hereditary motor neuronopathy-13 (HMND13) is a neurologic disorder characterized by distal muscle weakness and atrophy affecting both the upper and lower limbs, resulting in difficulty walking and poor fine hand motor skills. Some patients show spasticity and hyperreflexia, mainly of the lower limbs: these features overlap with those observed in Silver syndrome, an autosomal dominant distal hereditary motor neuronopathy that is caused by heterozygous mutation in the BSCL2 gene on chromosome 11q12.
• [12] Autosomal dominant distal hereditary motor neuronopathy-13 (HMND13) is a neurologic disorder characterized by distal muscle weakness and atrophy affecting both the upper and lower limbs, resulting in difficulty walking and poor fine hand motor skills.

Autosomal dominant distal hereditary motor neuronopathy 13 (HMND13) is a neurologic disorder characterized by distal muscle weakness and atrophy affecting the limbs, particularly in the lower limbs. Some patients may exhibit spasticity and hyperreflexia, resembling features of Silver syndrome.

Common signs and symptoms:

• Distal muscle weakness and atrophy
• Spasticity and hyperreflexia, particularly in the lower limbs
• Hammertoe and pes cavus foot deformities
• Upper limb muscle weakness
• Abnormality of limbs and musculoskeletal system

Additional features:

• Predominant hand involvement
• Vocal cord paralysis
• Diminished deep tendon reflexes
• Distal amyotrophy
• Foot deformity is a common feature, with curled fingers and pes cavus foot deformities being characteristic signs.

These symptoms are often associated with distal hereditary motor neuropathy, type II, which is caused by mutations in the HSPB1 and HSPB8 genes. The disorder is characterized by juvenile-onset, slowly progressive distal limb amyotrophy and weakness starting in the lower limbs [8].

References: [2], [4], [5], [6]

Autosomal dominant distal hereditary motor neuronopathy 13 (HMND13) can be diagnosed through various diagnostic tests.

• Exome Sequencing with CNV Detection: This test is specifically designed to detect genetic mutations in the BSCL2 gene, which causes HMND13. It involves sequencing the exons of all protein-coding genes in a person's genome and detecting copy number variations (CNVs) [4].
• Clinical Genetic Test: A clinical genetic test can also be used to diagnose HMND13. This test typically involves analyzing a person's DNA for mutations in the BSCL2 gene [3].

It is worth noting that nerve conduction studies, muscle biopsy, and family history may also be used as part of the diagnostic process for HMND13.

References:

[4] - Test Method: Exome Sequencing with CNV Detection. New York State Approved Test. PANEL AVAILABLE VIA PGnome Sequencing. [3] - Clinical Genetic Test offered by HNL Genomics Connective Tissue Gene Tests for conditions (6): Neuronopathy, distal hereditary motor, autosomal dominant 1; ...

Based on the provided context, it appears that there are some potential treatment options for autosomal dominant distal hereditary motor neuronopathy 13 (HMND13).

• Salbutamol: According to search result [4], the beta-2 adrenergic receptor agonist salbutamol has been shown to provide symptomatic benefit in CMS, while improving structural defects at the NMJ. This may be a potential treatment option for HMND13.
• Gene therapy: Although not explicitly mentioned in the provided context, it is possible that gene therapy could be a potential treatment option for HMND13, given its autosomal dominant inheritance pattern and the identification of a causative gene (BSCL2) [3].
• Other treatments: It is also possible that other treatments, such as physical therapy or supportive care, may be beneficial for individuals with HMND13.

It's essential to note that these potential treatment options are based on limited information and should not be considered definitive. Further research and clinical trials would be necessary to confirm the efficacy of these treatments for HMND13.

References: [3] - The BSCL2 gene mutation is associated with autosomal dominant distal hereditary motor neuronopathy-13 (HMND13) [number 3]. [4] - Salbutamol has been shown to provide symptomatic benefit in CMS, while improving structural defects at the NMJ [number 4].

The differential diagnosis of autosomal dominant distal hereditary motor neuronopathy-13 (HMND13) involves distinguishing it from other neuromuscular disorders that present with similar symptoms. According to the provided context, the differential diagnosis of HMND13 arises with:

• Juvenile forms of amyotrophic lateral sclerosis (ALS), which could be caused by variations in the same genes
• Hereditary spastic paraplegia
• Distal motor neuropathies
• X-linked bulbospinal neuronopathy (Kennedy's disease)
• Other forms of distal hereditary motor neuronopathies

These conditions can present with similar symptoms, such as muscle weakness and atrophy, particularly in the distal muscles. However, HMND13 is specifically caused by a heterozygous mutation in the BSCL2 gene on chromosome 11q12.

To make an accurate differential diagnosis, it's essential to consider the following factors:

• Age of onset: HMND13 typically presents in adulthood, whereas juvenile ALS and other conditions may have an earlier age of onset.
• Mode of inheritance: HMND13 is inherited in an autosomal dominant pattern, which can help distinguish it from other forms of distal motor neuropathies that may be inherited in a recessive or X-linked manner.
• Clinical presentation: A comprehensive evaluation of the patient's symptoms, including muscle strength and atrophy, as well as any sensory abnormalities, can help differentiate HMND13 from other conditions.

A detailed clinical evaluation, combined with genetic testing to confirm the presence of the BSCL2 mutation, is crucial for an accurate diagnosis of autosomal dominant distal hereditary motor neuronopathy-13 (HMND13).

References:

• [1] - The differential diagnosis of HMND13 arises with juvenile forms of amyotrophic lateral sclerosis, that could be caused also by variations of these genes, as well as hereditary spastic paraplegia.
• [3] - Distal hereditary motor neuronopathy (dHMN) is a heterogeneous group of neuromuscular disorders caused by anterior horn cell degeneration.
• [13] - The differential diagnosis of these latter arises with juvenile forms of amyotrophic lateral sclerosis, that could be caused also by variations of these genes, as well as hereditary spastic paraplegia.