[7] The classic triad of EDMD consists of early contractures, muscle weakness, and heart involvement, typically manifesting in adolescence.

[12][1] Weakness of the scapular fixators can cause a winged scapula,[1] which can impair the ability to lift the arms over the head and can be painful.

[citation needed] Weakness of the peroneal muscles can result in toe walking, which can present in the first decade of life.

[1] Involvement of the heart occurs in almost all cases, presenting as syncope in the second or third decades, or as sudden cardiac death.

[3] Of female carriers, 10-20% have abnormal heart rhythm or conduction, with increased risk of sudden cardiac death.

[3] Each gene implicated in EDMD provides instructions for making a protein that is associated with the nuclear envelope, which surrounds the nucleus of a cell.

[medical citation needed] Mutations of the genes SUN1 and SUN2 have each been shown to cause EDMD in single cases.

[3] Genetic mutations causing EDMD affect proteins comprising the nuclear membrane.

Metabolic functions should also be assessed, as lipodystrophy can co-occur with EDMD, by measuring levels of sugar, cholesterol, and triglycerides in the blood.

Tests useful for heart evaluation include electrocardiography (EKG), echocardiography (echo), cardiac MRI, and electrophysiology studies.

EKG, holter, and echo are recommended yearly, and additional tests can be indicated depending on heart involvement.

[citation needed] Although the root cause of EDMD is not currently treatable, its manifestations and complications can be treated.