Weakness of the muscles responsible for dorsiflexion of the foot, that is, of the movement of the toes towards the shin. The foot dorsiflexors include the tibialis anterior, the extensor hallucis longus, the extensor digitorum longus, and the peroneus tertius muscles.

Familial dilated cardiomyopathy is a genetic form of heart disease. It occurs when heart (cardiac) muscle becomes thin and weakened in at least one chamber of the heart, causing the open area of the chamber to become enlarged (dilated). As a result, the heart is unable to pump blood as efficiently as usual. To compensate, the heart attempts to increase the amount of blood being pumped through the heart, leading to further thinning and weakening of the cardiac muscle. Over time, this condition results in heart failure.\n\nIt usually takes many years for symptoms of familial dilated cardiomyopathy to cause health problems. They typically begin in mid-adulthood, but can occur at any time from infancy to late adulthood. Signs and symptoms of familial dilated cardiomyopathy can include an irregular heartbeat (arrhythmia), shortness of breath (dyspnea), extreme tiredness (fatigue), fainting episodes (syncope), and swelling of the legs and feet. In some cases, the first sign of the disorder is sudden cardiac death. The severity of the condition varies among affected individuals, even in members of the same family.

Hypertrophic cardiomyopathy (HCM) is defined by the presence of increased ventricular wall thickness or mass in the absence of loading conditions (hypertension, valve disease) sufficient to cause the observed abnormality.

Episodes of atrial fibrillation that typically last for several hours up to one day and terminate spontaneously.

Reduction of total body weight.

Difficulty in swallowing.

A type of hearing impairment in one or both ears related to an abnormal functionality of the cochlear nerve.

Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly).

Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed.

An unintentional, oscillating to-and-fro muscle movement about a joint axis.

Absence of neurologic reflexes such as the knee-jerk reaction.

An abnormality of the cerebral white matter.

Partial or complete wasting (loss) of brain tissue that was once present.

Sudden and involuntary contractions of one or more muscles.

Reduced strength of muscles.

A lack of strength of the proximal muscles.

Reduced ability to walk (ambulate).

Facial nerve palsy is a dysfunction of cranial nerve VII (the facial nerve) that results in inability to control facial muscles on the affected side with weakness of the muscles of facial expression and eye closure. This can either be present in unilateral or bilateral form.

Reduced strength of the musculature of the distal extremities.

The lysosomal-vacuolar pathway has a role in the controlled intracellular digestion of macromolecules such as protein complexes and organelles. This feature refers to the presence of an abnormally increased number of autophagic vacuoles in muscle tissue.

An abnormally high degree of muscle fiber size variation. This phenotypic feature can be observed upon muscle biopsy.

Muscular atrophy affecting muscles in the distal portions of the extremities.

Presence of abnormal vacuoles (membrane-bound organelles) in the sarcolemma. On histological staining with hematoxylin and eosin, rimmed vacuoles are popcorn-like clear vacuoles with a densely blue rim. The vacuoles are often associated with cytoplasmic and occasionally intranuclear eosinophilic inclusions.

The presence of abnormal electromyographic patterns indicative of myopathy, such as small-short polyphasic motor unit potentials.

High frequency discharges in electromyography (EMG) that vary in amplitude and frequency, waxing and waning continuously with firing frequencies ranging from 150/second down to 20/second and producing a sound that has been referred to as a dive bomber sound.

Abnormally elevated blood carbon dioxide (CO2) level.

Bowing (abnormal curvature) of the vocal folds.

Respiratory distress is objectively observable as the physical or emotional consequences from the experience of dyspnea. The physical presentation of respiratory distress is generally referred to as labored breathing, while the sensation of respiratory distress is called shortness of breath or dyspnea.

An abnormal reduction in the amount of air a person can expel following maximal inspiration.

Inspiration of a foreign object into the airway.

A functional defect characterized by reduced total lung capacity (TLC) not associated with abnormalities of expiratory airflow or airway resistance. Spirometrically, a restrictive defect is defined as FEV1 (forced expiratory volume in 1 second) and FVC (forced vital capacity) less than 80 per cent. Restrictive lung disease may be caused by alterations in lung parenchyma or because of a disease of the pleura, chest wall, or neuromuscular apparatus.

An elevation of the level of the enzyme creatine kinase (also known as creatine phosphokinase (CK; EC 2.7.3.2) in the blood. CK levels can be elevated in a number of clinical disorders such as myocardial infarction, rhabdomyolysis, and muscular dystrophy.

A type of speech characterized by the presence of an abnormally increased nasal airflow during speech associated with structural abnormality of the nasal passages.

Difficulty in speaking due to a physical disorder of the mouth, tongue, throat, or vocal cords. Associated with a known physical or neurological cause.

Height of the palate more than 2 SD above the mean (objective) or palatal height at the level of the first permanent molar more than twice the height of the teeth (subjective).

A facial appearance characteristic of myopathic conditions. The face appears expressionless with sunken cheeks, bilateral ptosis, and inability to elevate the corners of the mouth, due to muscle weakness.

The upper eyelid margin is positioned 3 mm or more lower than usual and covers the superior portion of the iris (objective); or, the upper lid margin obscures at least part of the pupil (subjective).

Paralysis of the external ocular muscles.

Ophthalmoplegia is a paralysis or weakness of one or more of the muscles that control eye movement.