VITAMIN B12 DEFICIENCY [DD]

Question 1

What is  VITAMIN B12 DEFICIENCY [DD]?

Accepted Answer

At present, no ‘gold standard’ test exists for the diagnosis of vitamin B12 defi ciency and as a consequence, the diagnosis requires consideration of both the clinical state of the patient and the results of investigations [Shipton MJ, Thachil J 2015]

Low vitamin B12 intake

- Vegetarianism
- Chronic alcoholism
- Older people
Autoimmune
- Pernicious anaemia
- Sjögren’s syndrome
Food-bound cobalamin malabsorption
- Atrophic gastritis
- Chronic gastritis

- Helicobacter pylori-associated gastritis

- Bacterial overgrowth

Surgery
- Post-gastrectomy
- Ileal resection
Malabsorption
- Small intestinal bacterial overgrowth
- Chronic pancreatic exocrine insufficiency
- Crohn’s disease
- Coeliac disease
- Achlorhydria
Obstetric/gynaecological
- Oral contraceptive
- Hormone replacement therapy
- Pregnancy
Genetic
- Transcobalamin II deficiency
Drugs
- Metformin
- Proton pump inhibitors
- Histamine H2-receptor antagonists

Question 2

What is the link to OMIM ?

Accepted Answer

OMIN ---

Question 3

Which enzymes are involved?

Accepted Answer

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Disease	VITAMIN B12 DEFICIENCY [DD]
OMIM	--- OMIM = Online Mendelian Inheritance of Men
Orphanet	---
Gene locus	Detail information to gene locus by the National Center for Biotechnology Information NCBI: MAJOR HISTOCOMPATIBILITY COMPLEX
ICD
Summary	At present, no ‘gold standard’ test exists for the diagnosis of vitamin B12 defi ciency and as a consequence, the diagnosis requires consideration of both the clinical state of the patient and the results of investigations [Shipton MJ, Thachil J 2015] Low vitamin B12 intake - Vegetarianism - Chronic alcoholism - Older people Autoimmune - Pernicious anaemia - Sjögren’s syndrome Food-bound cobalamin malabsorption - Atrophic gastritis - Chronic gastritis - Helicobacter pylori-associated gastritis - Bacterial overgrowth Surgery - Post-gastrectomy - Ileal resection Malabsorption - Small intestinal bacterial overgrowth - Chronic pancreatic exocrine insufficiency - Crohn’s disease - Coeliac disease - Achlorhydria Obstetric/gynaecological - Oral contraceptive - Hormone replacement therapy - Pregnancy Genetic - Transcobalamin II deficiency Drugs - Metformin - Proton pump inhibitors - Histamine H2-receptor antagonists
Laboratory findings	Homocysteine inc (plasma) Methylmalonic acid (plasma) Vitamin B12 dec (serum) Methylmalonic acid inc (urine)
Symptoms	abnormal movement anemia depression gait disturbance headache (severe, recurrent or occipital, migraine) megaloblastic anemia muscle weakness myelopathy peripheral neuropathy neutropenia (decreased neutrophils) onset, adolescent onset, childhood onset, infancy onset, neonatal pancytopenia psychosis thrombopenia, thrombocytopenia