Vitamin B7 deficiency: Difference between revisions
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==Clinical Features== | ==Clinical Features== | ||
===Classical Presentation=== | ===Classical Presentation=== | ||
* Dermatitis - specifically around eyes, nose, mouth | * [[rash|Dermatitis]] - specifically around eyes, nose, mouth | ||
* Alopecia | * [[Alopecia]] | ||
* Enteritis | * Enteritis ([[diarrhea]], [[nausea/vomiting]]) | ||
* Neurological - including [[AMS]], lethargy, [[hallucinations]], [[paresthesias]] | * Neurological - including [[AMS]], [[lethargy]], [[hallucinations]], [[paresthesias]] | ||
===Holocarboxylase Synthetase Deficiency=== | ===Holocarboxylase Synthetase Deficiency=== | ||
Presents in the first week of life with: | Presents in the first week of life with: | ||
* | * [[altered mental status (peds)|Lethargy]] | ||
* | * Hypotonia | ||
* | * [[Vomiting]] | ||
===Biotinidase Deficiency=== | ===Biotinidase Deficiency=== | ||
Presents later in life with: | Presents later in life with: | ||
* | * [[rash|Dermatitis]] | ||
* | * Neurological symptoms - [[ataxia]], [[seizures]], myoclonus, [[nystagmus]] | ||
* | * [[Ketonemia|Ketoacidosis]] | ||
==Differential Diagnosis== | ==Differential Diagnosis== | ||
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** Pyruvate Carboxylase Deficiency | ** Pyruvate Carboxylase Deficiency | ||
* Starvation | * Starvation | ||
* Medication Use - Antibiotics or | * Medication Use - [[Antibiotics]] or [[anticonvulsants]] | ||
* Other vitamin deficiencies: | * Other vitamin deficiencies: | ||
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==Management== | ==Management== | ||
* Supplementation of Biotin. Dosage is debated: | * Supplementation of [[Biotin]]. Dosage is debated: | ||
** 150 ug intramuscular injection suggested | ** 150 ug intramuscular injection suggested | ||
** 5-20 mg/dl have also been used | ** 5-20 mg/dl have also been used | ||
* Stop consumption of raw eggs. | * Stop consumption of raw eggs. | ||
* Stop anti-convulsant or anti-biotic | * Stop culprit anti-convulsant or anti-biotic | ||
==Disposition== | ==Disposition== | ||
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==See Also== | ==See Also== | ||
*[[Vitamin deficiencies]] | |||
*[[Inborn errors of metabolism]] | |||
==External Links== | ==External Links== |
Latest revision as of 17:02, 29 September 2019
Background
- Almost all food contain significant quantities of biotin, but it is most found in plants, liver, egg yolk, soybean products, and yeast.
- Daily biotin requirement is low (150-300 ug/d).
- Intestinal flora synthesizes significant quantities of biotin.
- Biotin is recycled in the body and eventually lost in urine and feces.
Cofactor in four major carboxylation reactions
- Acetyl-CoA Carboxylase (ACC) - Acetyl-CoA to Malonyl-CoA in Fatty Acid Synthesis
- Pyruvate Carboxylase (PC) - Pyruvate to Oxaloacetate in Gluconeogenesis
- Propinoyl-CoA Carboxylase (PCC) - Propinoyl-CoA to Methylmalonyl-CoA in Odd Chain Fatty Acid Metabolism
- Methylcrotonyl CoA Carboxylase (MCC) - 3-Methylcrotonyl CoA to 3-Methylglutaconyl CoA in Leucine Metabolism
Biotin deficiency risk factors
- Long-term Parenteral Nutrition
- Consumption of raw egg whites (bodybuilders or boxers)
Secondary biotin deficiency (Multiple Carboxylase Deficiency)
Is caused by two inherited defects in metabolism:
- Holocarboxylase Synthetase Deficiency - Autosomal Recessive disorder. Holocarboxylase Synthetase is required to attach biotin to other molecules. Deficiency in this enzyme prevents cells from using Biotin.
- Biotinidase Deficiency - Biotinidase is required to release Biotin that is bounded to protein.
Clinical Features
Classical Presentation
- Dermatitis - specifically around eyes, nose, mouth
- Alopecia
- Enteritis (diarrhea, nausea/vomiting)
- Neurological - including AMS, lethargy, hallucinations, paresthesias
Holocarboxylase Synthetase Deficiency
Presents in the first week of life with:
Biotinidase Deficiency
Presents later in life with:
- Dermatitis
- Neurological symptoms - ataxia, seizures, myoclonus, nystagmus
- Ketoacidosis
Differential Diagnosis
- DDx involves genetic disorders with impaired carboxylation.
- Biotinidase Deficiency (see above)
- Holocarboxylase Synthetase Deficiency (see above)
- Carnitine Deficiency
- Methylmalonic Acidemia
- Propionic Acidemia
- Pyruvate Carboxylase Deficiency
- Starvation
- Medication Use - Antibiotics or anticonvulsants
- Other vitamin deficiencies:
Vitamin deficiencies
- Vitamin A deficiency
- Vitamin B deficiencies
- Vitamin B1 deficiency (Thiamine)
- Vitamin B3 deficiency (Pellagra)
- Vitamin B7 deficiency (Biotin)
- Vitamin B9 deficiency (Folate)
- Vitamin B12 deficiency
- Vitamin C deficiency (Scurvy)
- Vitamin D deficiency (Rickets)
- Vitamin E deficiency
- Vitamin K deficiency
Evaluation
- Diagnosis is primarily clinical. Routine serum chemistry panel should be checked.
- Other Laboratory Studies
- Newborn Screening
- Serum Biotinidase Activity decreased
- Serum Ammonia Levels increased
- Plasma Carnitine
- Quantitative Amino Acid levels
- Urine B-Hydroxyisoverlate decreased
- Urine Biotin decreased
- Urine Ketones increased
Management
- Supplementation of Biotin. Dosage is debated:
- 150 ug intramuscular injection suggested
- 5-20 mg/dl have also been used
- Stop consumption of raw eggs.
- Stop culprit anti-convulsant or anti-biotic
Disposition
- Follow-up with primary care provider or referral to genetic specialist.