Book contents
- Frontmatter
- Contents
- Contributors
- Foreword
- Preface
- 1 Introduction
- 2 Genetics of neurocutaneous disorders
- 3 Clinical recognition
- 4 Neurofibromatosis type 1
- 5 Neurofibromatosis type 2
- 6 Tuberous sclerosis complex
- 7 von Hippel–Lindau disease
- 8 Neurocutaneous melanosis
- 9 Nevoid basal cell carcinoma (Gorlin) syndrome
- 10 Epidermal nevus syndromes
- 11 Multiple endocrine neoplasia type 2
- 12 Ataxia–telangiectasia
- 13 Incontinentia pigmenti
- 14 Hypomelanosis of Ito
- 15 Cowden disease
- 16 Pseudoxanthoma elasticum
- 17 Ehlers–Danlos syndromes
- 18 Hutchinson–Gilford progeria syndrome
- 19 Blue rubber bleb nevus syndrome
- 20 Hereditary hemorrhagic telangiectasia (Osler–Weber–Rendu)
- 21 Hereditary neurocutaneous angiomatosis
- 22 Cutaneous hemangiomas: vascular anomaly complex
- 23 Sturge–Weber syndrome
- 24 Lesch–Nyhan syndrome
- 25 Multiple carboxylase deficiency
- 26 Homocystinuria due to cystathionine β-synthase (CBS) deficiency
- 27 Fucosidosis
- 28 Menkes disease
- 29 Xeroderma pigmentosum, Cockayne syndrome and trichothiodystrophy
- 30 Cerebrotendinous xanthomatosis
- 31 Adrenoleukodystrophy
- 32 Peroxisomal disorders
- 33 Familial dysautonomia
- 34 Fabry disease
- 35 Giant axonal neuropathy
- 36 Chediak–Higashi syndrome
- 37 Encephalocraniocutaneous lipomatosis
- 38 Cerebello-trigemino-dermal dysplasia
- 39 Coffin–Siris syndrome: clinical delineation; differential diagnosis and long-term evolution
- 40 Lipoid proteinosis
- 41 Macrodactyly–nerve fibrolipoma
- Index
- References
25 - Multiple carboxylase deficiency
Published online by Cambridge University Press: 31 July 2009
- Frontmatter
- Contents
- Contributors
- Foreword
- Preface
- 1 Introduction
- 2 Genetics of neurocutaneous disorders
- 3 Clinical recognition
- 4 Neurofibromatosis type 1
- 5 Neurofibromatosis type 2
- 6 Tuberous sclerosis complex
- 7 von Hippel–Lindau disease
- 8 Neurocutaneous melanosis
- 9 Nevoid basal cell carcinoma (Gorlin) syndrome
- 10 Epidermal nevus syndromes
- 11 Multiple endocrine neoplasia type 2
- 12 Ataxia–telangiectasia
- 13 Incontinentia pigmenti
- 14 Hypomelanosis of Ito
- 15 Cowden disease
- 16 Pseudoxanthoma elasticum
- 17 Ehlers–Danlos syndromes
- 18 Hutchinson–Gilford progeria syndrome
- 19 Blue rubber bleb nevus syndrome
- 20 Hereditary hemorrhagic telangiectasia (Osler–Weber–Rendu)
- 21 Hereditary neurocutaneous angiomatosis
- 22 Cutaneous hemangiomas: vascular anomaly complex
- 23 Sturge–Weber syndrome
- 24 Lesch–Nyhan syndrome
- 25 Multiple carboxylase deficiency
- 26 Homocystinuria due to cystathionine β-synthase (CBS) deficiency
- 27 Fucosidosis
- 28 Menkes disease
- 29 Xeroderma pigmentosum, Cockayne syndrome and trichothiodystrophy
- 30 Cerebrotendinous xanthomatosis
- 31 Adrenoleukodystrophy
- 32 Peroxisomal disorders
- 33 Familial dysautonomia
- 34 Fabry disease
- 35 Giant axonal neuropathy
- 36 Chediak–Higashi syndrome
- 37 Encephalocraniocutaneous lipomatosis
- 38 Cerebello-trigemino-dermal dysplasia
- 39 Coffin–Siris syndrome: clinical delineation; differential diagnosis and long-term evolution
- 40 Lipoid proteinosis
- 41 Macrodactyly–nerve fibrolipoma
- Index
- References
Summary
Introduction
Biotin is an essential B-complex water-soluble vitamin. It was first recognized in 1936 after its isolation from egg yolk as a yeast growth factor (Wolf & Feldman, 1982). Biotin (C10H6O3N2S) consists of a heterocyclic ring with a side chain that ends in a carboxylic acid group. In humans, biotin functions as a transport protein to four major carboxylases: pyruvate carboxylase (PC), acetyl-CoA carboxylase (ACC), propionyl-CoA carboxylase (PCC), and 3-methylcrotonyl-CoA carboxylase (MCC). It is therefore involved in critical energy pathways for gluconeogenesis, fatty acid synthesis, catabolism of branched chain amino acids, and leucine catabolism respectively. The carboxyl group of biotin links covalently to the epsilon amino group of a lysine residue of these apocarboxylases. The result is the synthesis of an active holocarboxylase. A single enzyme, holocarboxylase synthetase catalyzes these steps (Fig. 25.1). Eventual degradation of the biotin–apocarboxylase complex results in biocytin that is then regenerated as free biotin by biotinidase (Wolf & Heard, 1991). Defective activity of either enzyme therefore leads to similar metabolic anomalies.
The clinical interest in inborn errors of biotin-related disorders began with Gompertz and colleagues' (Gompertz et al., 1971) first description of a newborn with metabolic acidosis and characteristic organic aciduria (β-methylcrotonylglycinuria and β-hydroxyisovaleric aciduria). These metabolic abnormalities disappeared with initiation of biotin treatment. Clinical improvement also followed. This seminal report fueled the growing interest in understanding the biochemical basis of diseases.
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- Information
- Neurocutaneous Disorders , pp. 200 - 205Publisher: Cambridge University PressPrint publication year: 2004