Difference between revisions of "Vitamin B7 deficiency"

(Vitamin deficiencies)
 
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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:
* lethargy
+
* [[altered mental status (peds)|Lethargy]]
* hypotonia
+
* Hypotonia
* vomiting
+
* [[Vomiting]]
  
 
===Biotinidase Deficiency===
 
===Biotinidase Deficiency===
 
Presents later in life with:
 
Presents later in life with:
* dermatitis
+
* [[rash|Dermatitis]]
* neurological symptoms - [[ataxia]], [[seizures]], myoclonus, nystagmus
+
* Neurological symptoms - [[ataxia]], [[seizures]], myoclonus, [[nystagmus]]
* ketoacidosis
+
* [[Ketonemia|Ketoacidosis]]
  
 
==Differential Diagnosis==
 
==Differential Diagnosis==
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** Pyruvate Carboxylase Deficiency
 
** Pyruvate Carboxylase Deficiency
 
* Starvation
 
* Starvation
* Medication Use - Antibiotics or Anti-convulsants
+
* Medication Use - [[Antibiotics]] or [[anticonvulsants]]
 
* Other vitamin deficiencies:
 
* Other vitamin deficiencies:
  
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***[[Wernicke-Korsakoff syndrome]]
 
***[[Wernicke-Korsakoff syndrome]]
 
**[[Vitamin B3 deficiency]] ([[Pellagra]])
 
**[[Vitamin B3 deficiency]] ([[Pellagra]])
**[[Vitamin B7 deficiency]]
+
**[[Vitamin B7 deficiency]] (Biotin)
 
**[[Vitamin B9 deficiency]] (Folate)
 
**[[Vitamin B9 deficiency]] (Folate)
 
**[[Vitamin B12 deficiency]]
 
**[[Vitamin B12 deficiency]]
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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 use.
+
* 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

  1. Acetyl-CoA Carboxylase (ACC) - Acetyl-CoA to Malonyl-CoA in Fatty Acid Synthesis
  2. Pyruvate Carboxylase (PC) - Pyruvate to Oxaloacetate in Gluconeogenesis
  3. Propinoyl-CoA Carboxylase (PCC) - Propinoyl-CoA to Methylmalonyl-CoA in Odd Chain Fatty Acid Metabolism
  4. Methylcrotonyl CoA Carboxylase (MCC) - 3-Methylcrotonyl CoA to 3-Methylglutaconyl CoA in Leucine Metabolism

Biotin deficiency risk factors

  1. Long-term Parenteral Nutrition
  2. Consumption of raw egg whites (bodybuilders or boxers)

Secondary biotin deficiency (Multiple Carboxylase Deficiency)

Is caused by two inherited defects in metabolism:

  1. 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.
  2. Biotinidase Deficiency - Biotinidase is required to release Biotin that is bounded to protein.

Clinical Features

Classical Presentation

Holocarboxylase Synthetase Deficiency

Presents in the first week of life with:

Biotinidase Deficiency

Presents later in life with:

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

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.

See Also

External Links

References