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11 Cards in this Set
- Front
- Back
Clinical Multiple Carboxylase Deficiency
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Synonym
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Biotinidase deficiency
Holocarboxylase synthetase deficiency |
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Inheritance
Prenatal |
Both autosomal recessive; holocarboxylase synthetase (HLCS) gene on 21 q22;
biotinidase (BTD) gene on 3p25 CVS/amniocentesis: biotinidase or holocarboxylase synthetase assay |
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Incidence
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Biotinidase deficiency: 1:70,000 to 80,000; M=F
Holocarboxylase synthetase deficiency: unknown, rare: M=F |
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Age at Presentation
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Biotinidase deficiency: approximately 6 months old
Holocarboxylase synthetase deficiency: first few days to months of life |
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Pathogenesis
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Mutations in HLCS or BTD render the patient deficient in holocarboxylase synthetase or biotiniclase respectively, resulting in decreased free serum biotin and metabolic acidosis with resultant phenotype
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Clinical
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Skin
Periorificial/generalized dermatitis with/without candida infection Hair Sparse to total alopecia Central Nervous System Hypotonia, seizures, ataxia, coma Gastrointestinal Vomiting (holocarboxylase synthetase deficiency) Eyes Optic atrophy (biotinidase deficiency) Ear Nose Throat High frequency hearing loss (biotinidase deficiency) Metabolism Metabolic acidosis, hyperammonernia, organic aciduria |
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D/Dx
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Atopic dermatitis
Seborrheic dermatitis Acrodermatitis enteropathica (p. 328) Mucocutaneous candidiasis Essential fatty acid deficiency |
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Lab
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Screen urine for organic aciduria
Serum biotinidase/holocarboxylase synthetase assay Screen blood metabolic acidosis, hyperammonemia |
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Management
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Biotin 10 mg per day for life
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Prognosis
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If biotin instituted prior to neurologic sequelae, normal life span with normal growth and development
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