Mutations in the PC gene reduce the amount of pyruvate carboxylase in cells or disrupt the enzymes activity. The missing or altered enzyme cannot carry out its essential role in generating glucose, which impairs the bodys ability to make energy in mitochondria. Additionally, a loss of pyruvate carboxylase allows potentially toxic compounds, such as lactic acid and ammonia, to build up and damage organs and tissues. Loss of pyruvate carboxylase function in the nervous system, particularly the role of the enzyme in myelin formation and neurotransmitter production, may contribute to the neurological features of pyruvate carboxylase deficiency. Diagnosis
Classification
There are at least three types of pyruvate carboxylase deficiency, which are distinguished by the severity of their signs and symptoms. Type A
Type A, which has been identified mostly in people from North America, has moderately severe symptoms that begin in infancy. Characteristic features include developmental delay and a buildup of lactic acid in the blood (lactic acidosis). Increased acidity in the blood can lead to vomiting, abdominal pain, extreme tiredness (fatigue), muscle weakness, and difficulty breathing. In some cases, episodes of lactic acidosis are triggered by an illness or periods without food. Children with pyruvate carboxylase deficiency type A typically survive only into early childhood. Type B
Pyruvate carboxylase deficiency type B has life-threatening signs and symptoms that become apparent shortly after birth. This form of the condition has been reported mostly in Europe, particularly France. Affected infants have severe lactic acidosis, a build-up of ammonia in the blood (hyperammonemia), and liver failure.
Ross syndrome consists of Adies syndrome (myotonic pupils and absent deep tendon reflexes) plus segmental anhidrosis (typically associated with compensatory hyperhidrosis).It was characterized in 1958 by A.T. Ross.By 1992, eighteen cases had been documented.Signs and Symptoms
Initial manifestations often include an abnormal segmental sweating response (described as hyperhidrosis or anhidrosis in some patients) and a tonic pupil. Other commonly reported symptoms included fatigue, chronic cough, and increased urinary frequency.Prognosis
Ross syndrome is a non life-threatening benign condition but delay in diagnosis can result in slow progression of autonomic symptoms. Epidemiology
Ross Syndrome is a progressive autonomic dysfunction that can occur in any age, ethnicity, or gender. The average age of diagnosis for Ross syndrome is 36 years and affects more females than males. See also
Hypohidrosis
List of cutaneous conditions

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