Many disorders of metabolism have a genetic component, or are presumed to do so, with research being directed at finding the factors responsible.
Sites listed here will be concerned with the signs, symptoms, treatment, research, and experience of people with inherited metabolic disorders.
Alkaptonuria, black urine disease or alcaptonuria is a rare inherited genetic disorder of phenylalanine and tyrosine metabolism.
A deficiency of the enzyme alpha 1-antitrypsin results in low levels or a lack of an essential blood protein that protects tissues in the lungs from being destroyed by enzymes released from the body's own white blood cells.
Amyloid (pronounced am'-i-loyd) is an abnormal protein that may be deposited in any of your body's tissues or organs. This abnormal protein comes from cells in your bone marrow. The disease known as amyloidosis (pronounced am-i-loy-do'-sis) results when enough amyloid protein builds up in one or more organs to cause the organ(s) to malfunction. The heart, kidneys, nervous system and gastro-intestinal tract are most often affected. From the Mayo Clinic Rochester
Aspartylglycosaminuria is a classical lysosomal storage disorder caused by defective activity of the lysosomal hydrolase aspartylglucosaminidase. First presentation is usually between two and four years of age, such young patients often suffering from prolonged upper respiratory infections. Developmental of both motor and cognitive skills lags steadily behind that of normal children, and at the puberty AGU patients are mildly or moderately mentally retarded. With increasing age overall performance further declines; the life span of severely retarded individuals is 45 to 50 years.
Congenital Chloride diarrhea (CLD) is an intestinal transport defect of chloride ions. Retention of intestinal chloride causes water retention, which leads to watery diarrhea with an abnormally high chloride concentration. This defect presents in utero, with hydramnion presumably due to intrauterine diarrhea. The gestational period is shortened, and newborn babies have abdominal distension and chronic watery diarrhea. If untreated the condition leads to severe electrolyte changes with a fatal outcome, or to permanent damage of kidneys and brain. Treatment with chloride substitution and control of electrolyte balance is effective and patients can live an almost normal life complicated only by relatively loose stools.
An inherited disorder of bilirubin metabolism in which bilirubin cannot be changed into its water-soluble form, bilirubin glucuronide. This is caused by an enzyme imbalance in the liver.
Cystinosis is a rare genetic disease affecting both children and adults.

Gilbert's Syndrome is a form of congenital hyperbilirubinemia, which is a condition where bilirubin is not properly processed by the liver.

Glutaricaciduria is a rare hereditary metabolic disorder, caused by a deficiency of the enzyme glutaryl-CoA dehydrogenase.
Gracile Syndrome is an autosomal recessive metabolic disorder presenting with fetal growth retardation, Fanconi type aminoaciduria, cholestasis, iron overload (liver hemosiderosis), profound lactic acidosis, and early death. It is sometimes known as Fellman syndrome.
A rare, genetic disorder caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase or HPRT.
LPI is an autosomally recessively inherited amino acid disorder due to defective transport of cationic amino acids lysine, arginine and ornithine in the intestine and kidney tubules. The absence or dysfunction of the transport process leads to low plasma and high urine concentration of the cationic (dibasic) amino acids. Clinical presentation of the disease usually takes place during the weaning period when breast feeding is replaced by cows milk and other high protein diets. Nausea, vomiting and mild diarrhea usually are the first symptoms followed by failure to thrive and growth retardation. Later liver and spleen become enlarged, muscles are hypotonic and osteoporosis can cause bone fractures. High protein intake can lead to hyperammonemia and even to coma, possibly accounting for the mild intellectual deficit found in few cases of LPI. Many patients have spontaneously developed aversion to protein rich food. A pulmonary complication of unknown mechanism, alveolar proteinosis has occurred in few patients during adulthood with fatal outcome.
Madelung's Disease (also called Multiple Symmetrical Lipomatosis [MSL], Benign Symmetric Lipomatosis or Lanois-Bensaude Syndrome) is a metabolic condition characterized by the growth of fatty masses around the face, back of the head, neck, upper arms, abdomen, back and upper leg in a very specific pattern or distribution. Unlike the usual lipoma, these benign, fatty masses are not enclosed within a membranous capsule with very distinct boundaries. It is because of this characteristic, as well as the absolute symmetry in their occurrence, that the condition is often dismissed as simple obesity.
Mannosidosis is a genetic disorder characterized by a lysosomal enzyme deficiency resulting in progressive mental and physical deterioration.
Site about and for those dealing with Maple Syrup Urine Disease (MSUD), an inherited metabolic disorder present in about four in a million births, that, untreated, causes mental retardation, physical disabilities and death.
A neuromuscular condition, it causes victims to experience fatigue and pain after only minimal exercise. It is caused by a genetic defect that results in a deficiency of a muscle enzyme.
Mucolipidosis is a group of inherited metabolic disorders that affect the body's ability to carry out the normal turnover of various materials within cells.
Mucopolysaccharides are long molecular chains of sugar. They are used by the body in the building of connective tissues. They must also be broken down and reused by the body. Children with MPS are unable to produce one of the enzymes essential to this task. Mucopolysaccharide diseases (or Mucopolysaccharidosis or MPS) are genetic diseases caused by recessive genes. There are seven Mucopolysaccharide (MPS) disorders. They are referred to as MPS I-VII but many of them go by the name of the doctor who first described the condition as well. Hunter syndrome, Hurler syndrome, Scheie syndrome, Sanfilippo syndrome, Maroteaux-Lamy syndrome, and Morquio disease are all Mucopolysaccharide diseases.
Nonketotic hyperglycinemia is an inborn error of glycine degradation pathway presenting during the first days, even hours, of the newborn and causing severe brain damage and often early death. Glycine acts as neurotransmitter and its increased concentration due to deficient degradation has brain damaging effect. NKH does not affect the intrauterine development but after normal delivery the disease presents during the first days of life - 66 percent of cases were symptomatic before 48 hrs of life in one large series. Patients develop lethargy and profound hypotonia and refuse to feed. Wandering eye movements and intermittent ophthalmoplegia are frequent. As the encephalopathy progresses to coma, the infants develop frequent sequential myoclonic jerks, apneic episodes and hiccups. Most patients do not survive this stage without assisted ventilation. Even with assisted ventilation about 30 percent of patients die during the neonatal period. The surviving infants usually regain spontaneous respiration by 3 weeks of age, but are severely brain damaged until death at the age of few months to several years. The diagnosis of NKH is based on increased concentration of glycine in urine, plasma and cerebrospinal fluid.
Phenylketonuria (PKU) is a genetic disorder that is characterized by an inability of the body to utilize the essential amino acid, phenylalanine.
The result of changes in the blood's nitrogen-containing substances, or porphyrins.
A disorder of branch-chain amino acid metabolism characterized by the build-up of propionic acid resulting in episodes of vomiting, dehydration, and severe metabolic acidosis.
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Sanfilippo Syndrome (MPS III), an autosomal recessive hereditary disorder, is characterized by severe mental deterioration, mild physical defects and the excretion of heparan sulfate in the urine. There are four types of Sanfilippo Syndrome; types A and B are the most common forms.
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Smith-Lemli-Opitz syndrome is a hereditary developmental disorder. It is characterized by nostrils that tilt forward (anteverted nares), drooping eyelids, webbing between the second and third toes, male genital abnormalities, mental retardation, and small stature.
Trimethylaminuria (TMAU), also known as fish odor syndrome or fish malodor syndrome, is a rare metabolic disorder that causes a defect in the normal production of the enzyme Flavin containing monooxygenase 3 (FMO3).When FMO3 is not working correctly, the body loses the ability to properly breakdown trimethylamine.
A rare genetic metabolic disorder characterized by lack of the enzyme fumarylacetoacetate hydrolase (FAH), which is needed to break down the amino acid tyrosine.
Zellweger Syndrome is a rare hereditary disorder affecting infants. It is characterized by reduction or absence of peroxisomes in the cells of the liver, kidneys, and brain.