Clinical Guidance

Laing distal myopathy may be caused by different types of variants in the distal myosin tail. These include missense changes that insert proline, or cause charge changes or deletion or insertion of amino acids . Charge reversal pathogenic variants in MYH7 including , , and can be associated with a Laing distal myopathy phenotype combined with cardiomyopathy [, , , ]. It has also been shown that missense pathogenic variants to proline and amino acid deletions (, ) or insertions can also be associated with a combined distal myopathy/cardiomyopathy phenotype .

Source: GeneReviews — "Laing Distal Myopathy"

Penetrance

Penetrance appears to be at least 85%. reported a large Spanish family in which the age of onset ranged from birth to the sixth decade; 15% of family members with the pathogenic variant were reported to be asymptomatic. (Note, however, that individual ages at the time of reporting were not clearly stated.) In one apparent instance of a de novo pathogenic variant, the supposedly unaffected father was found to have somatic mosaicism; however, when examined, he did have mild weakness .

Source: GeneReviews — "Laing Distal Myopathy"

Diagnostic Criteria

No consensus clinical diagnostic criteria for Laing distal myopathy have been published.

Suggestive Findings

Laing distal myopathy should be considered in individuals with the following findings .

Clinical findings

Source: GeneReviews — "Laing Distal Myopathy"

Differential Diagnosis

Other disorders to consider in the differential diagnosis of Laing distal myopathy are indicated in this section. Congenital Myopathy The early onset of Laing distal myopathy means that any of the milder congenital myopathies may be a differential diagnosis . Table 4a. Congenital Myopathies of Interest in the Differential Diagnosis of Laing Distal Myopathy

Management Guidelines

No clinical practice guidelines for Laing distal myopathy have been published.

Evaluations Following Initial Diagnosis

To establish the extent of disease and needs in an individual diagnosed with Laing distal myopathy, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended.

Table 5.

Recommended Evaluations Following Initial Diagnosis in Individuals with Laing Distal Myopathy

System/Concern | Evaluation | Comment

Muscle weakness

| Full neurologic exam review of early gross motor milestones | Exam should specifically look for tightening of Achilles tendon pattern of muscle weakness.

Cardiomyopathy

| Baseline eval w/cardiologist incl EKG echocardiogram |

Genetic

counseling | By genetics professionals1 | To inform affected persons their families re nature, MOI, implications of Laing distal myopathy to facilitate medical personal decision making

MOI = mode of inheritance

1. Medical geneticist, certified genetic counselor, or certified advanced genetic nurse

Treatment of Manifestations

Table 6.

Treatment of Manifestations in Individuals with Laing Distal Myopathy

Manifestation/Concern | Treatment | Considerations/Other

Distal leg weakness

| Physiotherapy | To prevent or treat tightening of Achilles tendon

Lightweight splinting of ankle (w/ankle-foot orthosis) | Considered for those w/more advanced disease

Cardiomyopathy

| Standard medical treatment under supervision of cardiologist |

Kyphoscoliosis

| Surgical stabilization of spine | Bracing is ge...

Source: GeneReviews — "Laing Distal Myopathy"

Therapies Under Investigation

Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for access to information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.

Source: GeneReviews — "Laing Distal Myopathy"

Surveillance Guidelines

Table 7. Recommended Surveillance for Individuals with Laing Distal Myopathy

Source: GeneReviews — "Laing Distal Myopathy"