The three main types of<unk>  classified on the basis of tissue-specific symptomatology and age of onset. Among the few people diagnosed with CPT2, some have unknown and/or novel mutations that place them outside these three categories while remaining positive for CPT2. Neonatal form The neonatal form is the least common clinical presentation of this disorder and is almost invariably fatal in rapid fashion regardless of intervention. Symptomatic onset has been documented just hours after birth to within 4 days of life. Affected newborns typically experience respiratory failure, low blood sugar, seizures, liver enlargement, liver failure, and heart enlargement with abnormal heart rhythms leading to cardiac arrest. In most cases, elements of abnormal brain and kidney development are apparent, sometimes even at prenatal ultrasound. Infants with the lethal neonatal form usually live no longer than a few months. Neuronal migration defects have also been documented, to which the CNS pathology of the disorder is often attributed. Infantile form Symptomatic presentation usually occurs between 6 and 24 months of age, but the majority of cases have been documented in children less than 1 year of age. The infantile form involves multiple organ systems and is primarily characterized by hypoketotic hypoglycemia (recurring attacks of abnormally low levels of fat breakdown products and blood sugar) that often results in loss of consciousness and seizure activity. Acute liver failure, liver enlargement, and cardiomyopathy are also associated with the infantile presentation of this disorder. Episodes are triggered by febrile illness, infection, or fasting. Some cases of sudden infant death syndrome are attributed to infantile CPT<unk>  deficiency at autopsy. Adult form This exclusively myopathic form is the most prevalent and least severe phenotypic presentation of this disorder. Characteristic signs and symptoms include rhabdomyolysis (breakdown of muscle fibers and subsequent release of myoglobin), myoglobinuria, recurrent muscle pain, and weakness. The myoglobin release causes the urine to be red or brown and is indicatory of damage being done to the kidneys which ultimately could result in kidney failure. Muscle weakness and pain typically resolves within hours to days, and patients appear clinically normal in the intervening periods between attacks. Symptoms are most often exercise-induced, but fasting, a high-fat diet, exposure to cold temperature, sleep deprivation, or infection (especially febrile illness) can also provoke this metabolic myopathy. In a minority of cases, disease severity can be exacerbated by three life-threatening complications resulting from persistent rhabdomyolysis: acute kidney failure, respiratory insufficiency, and episodic abnormal heart rhythms. Severe forms may have continual pain from general life activity. The adult form has a variable age of onset. The first appearance of symptoms usually occurs between 6 and 20 years of age but has been documented in patients as young as 8 months as well as in adults over the age of 50. Roughly 80% cases reported to date have been male.
Carnitine palmitoyltransferase II deficiency
Carnitine palmitoyltransferase I deficiency
Carnitine-acylcarnitine translocase deficiency
3-Methylcrotonyl-CoA carboxylase deficiency
Acyl-CoA oxidase deficiency
Malonyl-CoA decarboxylase deficiency
2-Methylbutyryl-CoA dehydrogenase deficiency
Pyruvate kinase deficiency