Table 1.

Hematology, chemistry and metabolite parameters in blood and CSF

At presentation (Blood)	Case 1	Case 2	Case 3	N ranges
ESR (mm/1st h)	12	N.D.	N.D.	<20
CRP (mg/L)	<3	4	14	<5
Hb (mmol/L)	5.2	2.0	4.0	6.0-8.9
MCV (fL)	89.7∗	110	85	75-95
Reticulocytes (%)	1.4	2.0	0.7	0.5-2
Red cell distribution width (%)	15.2	17.2	22.4	12-16
Leukocytes (109/L)	29.3	68.9	11.8	6-17
Thrombocytes (109/L)	147	159	93	150-600
% neutrophils	50.4	N.D.	60	35-75
% eosinophils	26.7	N.D.	14	2-10
% lymphocytes	21.7	N.D.	22	17-42
% monocytes	2.2	N.D.	1	5-12
% basophils	0	N.D.	0	0-2
% blasts	0	N.D.	0	neg
Coombs test	neg	N.D.	N.D.	neg
LDH (U/L)	2294	8298	3519	<300
Haptoglobin (mg/L)	1.2	<0.10	<0.10	0-2
Ferritin (μg/L)	860	N.D.	5200	<250
Folic acid (nmol/L)	4	N.D.	11.6	10-50
VitB12 (pmol/L)	359	N.D.	217	150-700
Homocysteine (μmol/L)	14†	N.D.	15†	0-9
Transcobalamin	normal	N.D.	N.D.	present
Thrombopoietin (U/mL)	280	N.D.	N.D.	<40
Creatinine (μmol/L)	26	32	32	35-80
ASAT (U/L)	47	330	22	<50
ALAT (U/L)	26	131	19	<60
CSF (with folinic acid supplementation)
5-MTHF (nmol/L)	N.D.	N.D.	374	105-233
Biopterin (nmol/L; for BH4+BH2)	N.D.	N.D.	22	10-50

Values represent the cell numbers and concentrations of the indicated parameters determined during the first week upon admission. Values outside of the age-related normal reference ranges are marked in bold.

ALAT, alanine amino transferase; ASAT, aspartate amino transferase; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; Hb, hemoglobin; LDH, lactate dehydrogenase; MCV, mean corpuscular volume; 5-MTHF, 5-methyltetrahydrofolate.

^∗Value at admission at an academic center, after the start of folic acid and vitamin B12 supplementation because of anemia and MCV of 105 fL. At admission, the bone marrow biopsy still showed megaloblastic anemia (Figure 1A).

^†Mildly increased, not compatible with homozygous MTHFR, CBS, or MS enzyme defect.