Methylcobalamin deficiency type cblG
General Information (adopted from Orphanet):
Synonyms, Signs: |
METHIONINE SYNTHASE DEFICIENCY HMAG METHYLCOBALAMIN DEFICIENCY, cblG TYPE HOMOCYSTINURIA-MEGALOBLASTIC ANEMIA DUE TO DEFECT IN COBALAMIN METABOLISM, cblG COMPLEMENTATION TYPE Functional methionine synthase deficiency type cblG |
Number of Symptoms | 23 |
OrphanetNr: | 2170 |
OMIM Id: |
250940
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ICD-10: |
E72.1 |
UMLs: |
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MeSH: |
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MedDRA: |
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Snomed: |
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Prevalence, inheritance and age of onset:
Prevalence: | 33 cases [Orphanet] |
Inheritance: |
Autosomal recessive [Orphanet] |
Age of onset: |
All ages [Orphanet] |
Disease classification (adopted from Orphanet):
Parent Diseases: |
Genetic thrombotic microangiopathy
-Rare genetic disease Homocystinuria without methylmalonic aciduria -Rare genetic disease -Rare hematologic disease -Rare neurologic disease Thrombotic microangiopathy -Rare renal disease |
Symptom Information:
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(HPO:0002156) | Homocystinuria | 12 / 7739 | ||||
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(HPO:0000639) | Nystagmus | rare [HPO:skoehler] | 555 / 7739 | |||
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(HPO:0000618) | Blindness | rare [HPO:skoehler] | 124 / 7739 | |||
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(HPO:0000572) | Visual loss | 272 / 7739 | ||||
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(HPO:0002370) | Poor coordination | 15 / 7739 | ||||
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(HPO:0001288) | Gait disturbance | 318 / 7739 | ||||
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(HPO:0001263) | Global developmental delay | 853 / 7739 | ||||
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(HPO:0001250) | Seizures | 1245 / 7739 | ||||
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(HPO:0001249) | Intellectual disability | 1089 / 7739 | ||||
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(HPO:0008872) | Feeding difficulties in infancy | 153 / 7739 | ||||
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(HPO:0001508) | Failure to thrive | 454 / 7739 | ||||
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(HPO:0001889) | Megaloblastic anemia | 28 / 7739 | ||||
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(HPO:0003223) | Decreased methylcobalamin | 11 / 7739 | ||||
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(HPO:0003524) | Decreased methionine synthase activity | 9 / 7739 | ||||
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(HPO:0002160) | Hyperhomocystinemia | 10 / 7739 | ||||
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(HPO:0003658) | Hypomethioninemia | 6 / 7739 | ||||
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(HPO:0010547) | Muscle flaccidity | 466 / 7739 | ||||
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(HPO:0008947) | Infantile muscular hypotonia | 482 / 7739 | ||||
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(HPO:0001252) | Muscular hypotonia | 990 / 7739 | ||||
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(HPO:0001324) | Muscle weakness | 859 / 7739 | ||||
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(HPO:0000007) | Autosomal recessive inheritance | 2538 / 7739 | ||||
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(HPO:0002059) | Cerebral atrophy | 171 / 7739 | ||||
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(HPO:0003593) | Infantile onset | 249 / 7739 |
Associated genes:
ClinVar (via SNiPA)
Gene symbol | Variation | Clinical significance | Reference |
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Additional Information:
Description: (OMIM) |
Homocystinuria and megaloblastic anemia is an autosomal recessive inborn error of metabolism resulting from defects in the cobalamin (vitamin B12)-dependent pathway that converts homocysteine to methionine, which is catalyzed by methionine synthase. Clinical features are somewhat variable, but ... |
Clinical Description OMIM |
Thomas et al. (1985) and Rosenblatt et al. (1987) reported a boy with methylcobalamin deficiency who presented at age 6 weeks with lethargy, staring spells and vomiting after varicella infection. He was hypotonic and unresponsive to stimuli and ... |
Molecular genetics OMIM |
Gulati et al. (1996) analyzed the molecular basis for methionine synthase deficiency in cell lines derived from 2 cblG patients. The 79/76 cell line had low levels of methionine synthase activity and a diminished level of methionine synthase ... |