Table 2. [Metabolite Concentrations in Disorders of Intracellular Cobalamin Metabolism]. - GeneReviews®

	Methylmalonic Acid	Plasma Total Homocysteine (tHcy)	Plasma Methionine
Biochemical Phenotype	Complementation Group	Normal Values
<4 mmol/mol/Cr ¹	<0.27 µmol/L ¹	3-13 µmol/L	11-37 µmol/L
Values by Biochemical Phenotype
Combined AdoCbl & MeCbl deficiency	cblC ¹	100s to low 1,000s of mmol/mol Cr when ill or at presentation; generally ranging from 10s to 100s mmol/mol Cr during treatment	100s of µmol/L at presentation and when ill; 1-10 µmol/L when well & treated ²	>100 when ill; 20-80 µmol/L when well & treated ²	Low to normal
cblD-combined ³	Can be >1,000 mmol/mol Cr	NR	>100 µmol/L in some cases	Low to normal
cblF ⁴	200 mmol/mol/Cr when untreated; normal during treatment	Normal when treated	Increased when untreated; normal when treated	Normal
cblJ ⁵	Increased	Increased	Increased	Low to normal
cblX ^6, 7, 8	Increased	Increased	Normal to increased	Low to normal
MeCbl deficiency	cblD-homocystinuria ³	Normal	Normal	>100 µmol/L in some cases	Low to normal
cblE	Normal ⁹	Normal	>100 µmol/L when ill	Low ¹⁰
cblG	Normal	Normal	Increased	Low ¹⁰

Methylmalonic Acid

Plasma Total Homocysteine (tHcy)

Plasma Methionine

Urine

Blood

Biochemical Phenotype

Complementation Group

Normal Values

<4 mmol/mol/Cr ¹

<0.27 µmol/L ¹

3-13 µmol/L

11-37 µmol/L

Values by Biochemical Phenotype

Combined AdoCbl & MeCbl deficiency

cblC ¹

100s to low 1,000s of mmol/mol Cr when ill or at presentation; generally ranging from 10s to 100s mmol/mol Cr during treatment

100s of µmol/L at presentation and when ill; 1-10 µmol/L when well & treated ²

>100 when ill; 20-80 µmol/L when well & treated ²

Low to normal

cblD-combined ³

Can be >1,000 mmol/mol Cr

>100 µmol/L in some cases

Low to normal

cblF ⁴

200 mmol/mol/Cr when untreated; normal during treatment

Normal when treated

Increased when untreated; normal when treated

Normal

cblJ ⁵

Increased

Low to normal

cblX ^6, 7, 8

Increased

Normal to increased

Low to normal

MeCbl deficiency

cblD-homocystinuria ³

Normal

>100 µmol/L in some cases

Low to normal

cblE

Normal ⁹

Normal

>100 µmol/L when ill

Low ¹⁰

cblG

Normal

Increased

Low ¹⁰

From: Disorders of Intracellular Cobalamin Metabolism

GeneReviews^® [Internet].

Adam MP, Feldman J, Mirzaa GM, et al., editors.

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