Transcobalamin deficiency

General Information (adopted from Orphanet):

Synonyms, Signs: TC II DEFICIENCY
TCN2 DEFICIENCY
Inherited deficiency of transcobalamin
Transcobalamin II deficiency
Number of Symptoms 35
OrphanetNr: 859
OMIM Id: 275350
ICD-10: D51.2
UMLs: C0342701
MeSH:
MedDRA:
Snomed: 237934001

Prevalence, inheritance and age of onset:

Prevalence: No data available.
Inheritance: Autosomal recessive
[Orphanet]
Age of onset: Neonatal
Infancy
[Orphanet]

Disease classification (adopted from Orphanet):

Parent Diseases: Constitutional megaloblastic anemia due to vitamin B12 metabolism disorder
 -Rare genetic disease
 -Rare hematologic disease
Disorder of cobalamin metabolism and transport
 -Rare genetic disease

Symptom Information: Sort by abundance 

1
 (HPO:0012120) Methylmalonic aciduria 20 / 7739
2
 (HPO:0000153) Abnormality of the mouth 60 / 7739
3
 (HPO:0002066) Gait ataxia 327 / 7739
4
 (HPO:0002311) Incoordination 84 / 7739
5
 (HPO:0001254) Lethargy 104 / 7739
6
 (HPO:0001249) Intellectual disability 1089 / 7739
7
 (HPO:0000737) Irritability 93 / 7739
8
 (HPO:0001251) Ataxia 413 / 7739
9
 (HPO:0002013) Vomiting 191 / 7739
10
 (HPO:0002014) Diarrhea 225 / 7739
11
 (HPO:0001508) Failure to thrive 454 / 7739
12
 (HPO:0001972) Macrocytic anemia 26 / 7739
13
 (HPO:0001875) Neutropenia 83 / 7739
14
 (HPO:0002720) IgA deficiency 33 / 7739
15
 (HPO:0001873) Thrombocytopenia Frequent [Orphanet] 224 / 7739
16
 (HPO:0001903) Anemia Very frequent [Orphanet] 289 / 7739
17
 (HPO:0001876) Pancytopenia 89 / 7739
18
 (HPO:0010701) Abnormal immunoglobulin level Frequent [Orphanet] 49 / 7739
19
 (HPO:0001896) Reticulocytopenia 12 / 7739
20
 (HPO:0001980) Megaloblastic bone marrow 5 / 7739
21
 (HPO:0001874) Abnormality of neutrophils Frequent [Orphanet] 47 / 7739
22
 (HPO:0002850) IgM deficiency 18 / 7739
23
 (HPO:0004315) IgG deficiency 38 / 7739
24
 (HPO:0001888) Lymphopenia Frequent [Orphanet] 43 / 7739
25
 (HPO:0003220) Abnormality of chromosome stability Very frequent [Orphanet] 98 / 7739
26
 (HPO:0001939) Abnormality of metabolism/homeostasis Very frequent [Orphanet] 328 / 7739
27
 (HPO:0001324) Muscle weakness 859 / 7739
28
 (OMIM) Transcobalamin II deficiency 1 / 7739
29
 (HPO:0000007) Autosomal recessive inheritance 2538 / 7739
30
 (OMIM) Decreased IgG 5 / 7739
31
 (OMIM) Reduced unsaturated serum cobalamin binding capacity 1 / 7739
32
 (OMIM) Normal serum cobalamin 7 / 7739
33
 (OMIM) Normal serum folate 2 / 7739
34
 (MedDRA:10028124) Mucosal ulceration 1 / 7739
35
 (OMIM) Abnormal Schilling test (not normalized by addition of intrinsic factor) 1 / 7739

Associated genes:

ClinVar (via SNiPA)

Gene symbol Variation Clinical significance Reference

Additional Information:

Description: (OMIM) Transcobalamin II deficiency is an autosomal recessive disorder with onset in early infancy characterized by failure to thrive, megaloblastic anemia, and pancytopenia. Other features include methylmalonic aciduria, recurrent infections, and vomiting and diarrhea. Treatment with cobalamin results in ...
Diagnosis OMIM Because of the evidence presented by Porck et al. (1983) that the TC II of cord blood is of fetal origin, cord blood can be used in the neonatal diagnosis of deficiency.

Mayes et al. (1987) ...
Clinical Description OMIM Hakami et al. (1971) described megaloblastic anemia and other manifestations of vitamin B12 deficiency in 2 infant sibs who had normal levels of serum B12. Deficiency of transcobalamin II was demonstrated. A partial deficiency in both parents and ...
Molecular genetics OMIM Since TC2 synthesis had been demonstrated in cultured skin fibroblasts from normal patients, Li et al. (1994) studied skin fibroblasts from an affected child and his parents. They found that the affected child was a compound heterozygote with ...