Home > Encyclopedia of Neurological Disorders > Paramyotonia Congenita

Definition

Paramyotonia congenita is an inherited condition that causes stiffness and enlargement of muscles, particularly leg muscles.

Description

Paramyotonia congenita is passed on in families as an autosomal dominant trait. This means that males and females are affected equally; it also means that if one parent has the trait, the offspring have a 75% chance of also having the condition.

Demographics

Paramyotonia congenita is present from birth on. In some cases, the symptoms appear to grow more mild as the patient ages.

Causes and symptoms

Paramyotonia congenita is believed to be caused by a defect in the chloride channels of the muscles. As a result, the relaxation phase of the muscles is impaired, resulting in prolonged muscle contraction and stiffness. This "overuse" of the muscle results in the muscle becoming enlarged and bulky (called muscle hypertrophy).

Symptoms...