Biotinidase deficiency

Infobox_Disease
Name = PAGENAME


Caption = Biotin
DiseasesDB = 29822
ICD10 =
ICD9 = ICD9|277.6
ICDO =
OMIM = 253260
MedlinePlus =
eMedicineSubj = ped
eMedicineTopic = 239
MeshID = D028921

Biotinidase deficiency is an autosomal recessive metabolic disorder in which the body is not able to process the nutrient biotin properly.

Biotin, sometimes called vitamin H, is an important water-soluble nutrient that aids in the metabolism of fats, carbohydrates and proteins. Biotin Deficiency can result in behavioral disorders, lack of coordination, learning disabilities and seizure. Biotin supplementation can alleviate and sometimes totally arrest such symptoms.

Epidemiology

Approximately 1 in 60,000 newborns are affected by profound (less than 10 percent of normal enzyme activity) or partial (10-30 percent of normal enzyme activity) biotinidase deficiency.

Genetics

Mutations in the "BTD" gene cause biotinidase deficiency. Biotinidase is the enzyme that is made by the BTD gene. Many mutations that cause the enzyme to be nonfunctional or to be made at extremely low levels have been identified. Biotin is a vitamin that is chemically bound to proteins. (Most vitamins are only loosely associated with proteins.) Without biotinidase activity, the vitamin biotin cannot be separated from foods and therefore cannot be used by the body. Another function of the biotinidase enzyme is to recycle biotin from enzymes that are important in metabolism (processing of substances in cells). When biotin is lacking, specific enzymes called carboxylases cannot process proteins, fats, or carbohydrates. Individuals lacking biotinidase activity can still have normal carboxylases if they ingest small amounts of biotin.

This condition is inherited in an autosomal recessive pattern, which means the defective gene is located on an autosome, and two copies of the defective gene - one from each parent - must be inherited for a person to be affected by the disorder. The parents of a child with an autosomal recessive disorder are usually not affected by the disorder, but are carriers of one copy of the defective gene.

ee also

* Biotin deficiency

External links

References

* PMID 12618081
* PMID 12055344
* PMID 15060693
* PMID 15230462
* PMID 12791199