Brody myopathy, also called Brody disease, is a rare disorder that affects skeletal muscle function. BD was first characterized in 1969 by Dr. Irwin A. Brody at Duke University Medical Center. Individuals with BD have difficulty relaxing their muscles after exercise. This difficulty in relaxation leads to symptoms including cramps, stiffness, and discomfort in the muscles of the limbs and face. Symptoms are heightened by exercise and commonly progress in severity throughout adulthood. Signs and symptoms
Symptoms include stiffness and sometimes muscle cramping after exercise and especially when exposed to cold. The most commonly affected muscles are in the arms, legs, and eyelids. Individuals with Brody myopathy also sometimes experience weakness, myalgia, and rhabdomyolysis. Cause
Most cases of BD are inherited through autosomal recessive mutations in ATP2A1,  where each copy of the affected individuals gene contain a mutation. The gene involved in BD encodes the fast-twitch skeletal muscle ATPase, SERCA1. SERCA1 is a protein pump that uses ATP to pump Ca2+ ions from the cytosol to the sarcoplasmic reticulum in skeletal muscle. In those with BD, SERCA1 pumps are unable to effectively move Ca2+ across the membrane, leading to increased levels of cytoplasmic Ca2+. Increases in cytoplasmic Ca2+ levels interfere with muscle contraction, leading to the characteristic symptoms of BD.In some cases of BD, no mutations in ATP2A1 have been observed. Disease transmission in cases of non-ATP2A1 BD have been characterized as autosomal dominant pattern of inheritance.
Carnitine palmitoyltransferase I deficiency is a rare metabolic disorder that prevents the body from converting certain fats called long-chain fatty acids into energy, particularly during periods without food. It is caused by a mutation in CPT1A on chromosome 11.Carnitine, a natural substance acquired mostly through the diet, is used by cells to process fats and produce energy. People with this disorder have a faulty enzyme, carnitine palmitoyltransferase I, that prevents these long-chain fatty acids from being transported into the mitochondria to be broken down. Symptoms and signs
Signs and symptoms of this disorder include low levels of ketones (hypoketosis) and low blood sugar (hypoglycemia). Together these signs are called hypoketotic hypoglycemia. People with this disorder typically also have an enlarged liver (hepatomegaly), muscle weakness, and elevated levels of carnitine in the blood. Genetics
Mutations in the CPT1A gene cause carnitine palmitoyltransferase I deficiency by producing a defective version of an enzyme called carnitine palmitoyltransferase I. Without this enzyme, long-chain fatty acids from food and fats stored in the body cannot be transported into mitochondria to be broken down and processed. As a result, excessive levels of long-chain fatty acids may more rapidly build up in tissues, damaging the liver, heart and/or brain. This condition has an autosomal recessive inheritance pattern, which means the defective gene must be inherited from both parents.