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Table 2 Patient plasma and fibroblast biochemical analyses

From: Specific combination of compound heterozygous mutations in 17β-hydroxysteroid dehydrogenase type 4 (HSD17B4) defines a new subtype of D-bifunctional protein deficiency

Test Units Patient 1 Patient 2 Reference range
Plasma:     
VLCFA concentration     
 C26:0 Hexacosanoic μg/mL 0.220 0.270 0.23 ± 0.09*
 C26/C22   0.021 0.012 0.01 ± 0.004*
 C24/C22   0.918 0.967 0.84 ± 0.918*
 Phytanic acid μg/mL 1.260 0.810 < 3.0
 Pristanic acid μg/mL 0.140 0.060 < 0.3
Fibroblasts:     
Catalase immunofluorescence   Near-normal Normal Normal
VLCFA concentration:     
 C26:0 concentration μmol / g protein 0.20 0.20 0.18 - 0.38
 C24:0 concentration μmol / g protein 6.52 6.79 7.76 - 17.66
 C22:0 concentration μmol / g protein 3.00 3.23 3.84 - 10.20
 Ratio C26:0 / C 22:0   0.07 0.06 0.03 - 0.07
 Ratio C24:0 / C 22:0   2.18 2.10 1.55 - 2.30
Peroxisome function:     
 β-oxidation (of C16:0) pmol / (mg protein / hour) 3876 5061 3330 - 7790
 β-oxidation (of C26:0) pmol / (mg protein / hour) 1290 1325 800 - 2040
 β-oxidation (of pristanic acid) pmol / (mg protein / hour) 157 248 790 - 1690
 α-oxidation (of phytanic acid) pmol / (mg protein / hour) 38 45 28 - 95
D-bifunctional protein activity:     
 Hydratase pmol / (mg protein / min) 43 53 115 - 600
 Dehydrogenase pmol / (mg protein / min) 2 3 25 - 300
Immunoblotting:     
 DBP 79 kDa   Trace Trace Present
 DBP 45 kDa   Absent Absent Present
 DBP 35 kDa   ±/− ±/− Present
  1. Plasma testing was performed at Kennedy-Krieger Institute (Baltimore, USA). Fibroblast testing was performed at the Laboratory Genetic Metabolic Diseases (Amsterdam, The Netherlands).
  2. Bold and underlined values are abnormal; *Indicates mean +/− 1 standard deviation.