Homocystinuria or HCU is an inherited disorder of the metabolism of the amino acid methionine due to a deficiency of cystathionine beta synthase or methionine synthase. It is an inherited autosomal recessive trait, which means a child needs to inherit a copy of the defective gene from both parents to be affected. Symptoms of homocystinuria can also be caused by a deficiency of vitamins B6, B12, or folate.
Autism spectrum disorders (ASD) are neurodevelopmental disorders that begin in early childhood, persist throughout adulthood, and affect three crucial areas of development: communication, social interaction and restricted patterns of behavior. There are many conditions comorbid to autism spectrum disorders such as attention-deficit hyperactivity disorder and epilepsy.
Folinic acid, also known as leucovorin, is a medication used to decrease the toxic effects of methotrexate and pyrimethamine. It is also used in combination with 5-fluorouracil to treat colorectal cancer and pancreatic cancer, may be used to treat folate deficiency that results in anemia, and methanol poisoning. It is taken by mouth, injection into a muscle, or injection into a vein.
Menkes disease (MNK), also known as Menkes syndrome, is an X-linked recessive disorder caused by mutations in genes coding for the copper-transport protein ATP7A, leading to copper deficiency. Characteristic findings include kinky hair, growth failure, and nervous system deterioration. Like all X-linked recessive conditions, Menkes disease is more common in males than in females. The disorder was first described by John Hans Menkes in 1962.
Maple syrup urine disease (MSUD) is an autosomal recessive metabolic disorder affecting branched-chain amino acids. It is one type of organic acidemia. The condition gets its name from the distinctive sweet odor of affected infants' urine and earwax, particularly prior to diagnosis and during times of acute illness. It was described by John Menkes in the 1950s.
Glutaric acidemia type 1 (GA1) is an inherited disorder in which the body is unable to completely break down the amino acids lysine, hydroxylysine and tryptophan. Excessive levels of their intermediate breakdown products can accumulate and cause damage to the brain, but particularly the basal ganglia, which are regions that help regulate movement. GA1 causes secondary carnitine deficiency, as glutaric acid, like other organic acids, is detoxified by carnitine. Mental retardation may occur.
Biotinidase deficiency is an autosomal recessive metabolic disorder in which biotin is not released from proteins in the diet during digestion or from normal protein turnover in the cell. This situation results in biotin deficiency.
Tetrahydrobiopterin deficiency (THBD, BH4D) is a rare metabolic disorder that increases the blood levels of phenylalanine. Phenylalanine is an amino acid obtained normally through the diet, but can be harmful if excess levels build up, causing intellectual disability and other serious health problems. In healthy individuals, it is metabolised (hydroxylated) into tyrosine, another amino acid, by phenylalanine hydroxylase. However, this enzyme requires tetrahydrobiopterin as a cofactor and thus its deficiency slows phenylalanine metabolism.
Glycine encephalopathy is a rare autosomal recessive disorder of glycine metabolism. After phenylketonuria, glycine encephalopathy is the second most common disorder of amino acid metabolism. The disease is caused by defects in the glycine cleavage system, an enzyme responsible for glycine catabolism. There are several forms of the disease, with varying severity of symptoms and time of onset. The symptoms are exclusively neurological in nature, and clinically this disorder is characterized by abnormally high levels of the amino acid glycine in bodily fluids and tissues, especially the cerebrospinal fluid.
Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a rare autosomal recessive disorder of the degradation pathway of the inhibitory neurotransmitter γ-aminobutyric acid, or GABA. The disorder has been identified in approximately 350 families, with a significant proportion being consanguineous families. The first case was identified in 1981 and published in a Dutch clinical chemistry journal that highlighted a number of neurological conditions such as delayed intellectual, motor, speech, and language as the most common manifestations. Later cases reported in the early 1990s began to show that hypotonia, hyporeflexia, seizures, and a nonprogressive ataxia were frequent clinical features as well.
Folate deficiency, also known as vitamin B9 deficiency, is a low level of folate and derivatives in the body. This may result in a type of anemia in which red blood cells become abnormally large and is a late finding in folate deficiency and folate deficiency anemia is the term given for this medical condition. Signs of folate deficiency are often subtle. Symptoms may include feeling tired, heart palpitations, shortness of breath, feeling faint, open sores on the tongue, loss of appetite, changes in the color of the skin or hair, irritability, and behavioral changes. Temporary reversible infertility may occur. Folate deficiency anemia during pregnancy may give rise to the birth of low weight birth premature infants and infants with neural tube defects.
GLUT1 deficiency syndrome, also known as GLUT1-DS, De Vivo disease or Glucose transporter type 1 deficiency syndrome, is an autosomal dominant genetic metabolic disorder associated with a deficiency of GLUT1, the protein that transports glucose across the blood brain barrier. Glucose Transporter Type 1 Deficiency Syndrome has an estimated birth incidence of 1 in 90,000 to 1 in 24,300. This birth incidence translates to an estimated prevalence of 3,000 to 7,000 in the U.S.
Folate receptor 1 is a protein that in humans is encoded by the FOLR1 gene.
Nutritional neuroscience is the scientific discipline that studies the effects various components of the diet such as minerals, vitamins, protein, carbohydrates, fats, dietary supplements, synthetic hormones, and food additives have on neurochemistry, neurobiology, behavior, and cognition.
Creatine transporter deficiency (CTD) is an inborn error of creatine metabolism in which creatine is not properly transported to the brain and muscles due to defective creatine transporters. CTD is an X-linked disorder caused by mutation in SLC6A8. SLC6A8 is located at Xq28. Hemizygous males with CTD express speech and behavior abnormalities, intellectual disabilities, development delay, seizures, and autistic behavior. Heterozygous females with CTD generally express fewer, less severe symptoms. CTD is one of three different types of cerebral creatine deficiency (CCD). The other two types of CCD are guanidinoacetate methyltransferase (GAMT) deficiency and L-arginine:glycine amidinotransferase (AGAT) deficiency. Clinical presentation of CTD is similar to that of GAMT and AGAT deficiency. CTD was first identified in 2001 with the presence of a hemizygous nonsense change in SLC6A8 in a male patient.
Hereditary folate malabsorption (HFM) is a rare autosomal recessive disorder caused by loss-of-function mutations in the proton-coupled folate transporter (PCFT) gene, resulting in systemic folate deficiency and impaired delivery of folate to the brain.
Aromatic L-amino acid decarboxylase deficiency, also known as AADC deficiency, is a rare genetic disorder caused by mutations in the DDC gene, which encodes an enzyme called aromatic L-amino acid decarboxylase.
5,10-Methenyltetrahydrofolate synthetase deficiency is a rare neurodevelopmental disorder caused by mutations affecting the MTHFS gene, which encodes the enzyme 5,10-Methenyltetrahydrofolate synthetase.
Dihydropteridine reductase deficiency (DHPRD) is a genetic disorder affecting the tetrahydrobiopterin (BH4) synthesis pathway, inherited in the autosomal recessive pattern. It is one of the six known disorders causing tetrahydrobiopterin deficiency, and occurs in patients with mutations of the QDPR gene.
Dihydrofolate reductase deficiency is a rare inherited disorder of folate metabolism caused by defects in the DHFR gene. The disorder is inherited in the autosomal recessive manner and may present with megaloblastic anemia, cerebral folate deficiency and neurological symptoms of varying type and severity. The patient may have a developmental delay and develop epileptic seizures.
