TABLE 3.
LC-MS/MS analysis of 5β-cholestane-25-tetrol-glucuronide, tCDCA, and 7α12αC4 in around 5% of total DBSs as a test for CTX
| DBS from: | Ratio 5β-Cholestane-25-tetrol-glucuronide/tCDCA | 5β-Cholestane-25-tetrol-glucuronide (ng/ml) | tCDCA (ng/ml) | 7α12αC4 (ng/ml) |
| CTX untreated adults/children (n = 12) | 202.9312 (1.7446–785.6219) | 6,100 (584–10,039) | 62 (0–329) | 2,423 (268–3,669) |
| CTX treated adults/children (n = 8) | 87.8009 (0.4540–645.3804) | 2,017 (146–8,652) | 47 (0–129) | 515 (18.0–2,075) |
| CTX untreated newborns (n = 3) | 3.8707b (0.3301–6.3481) | 548b (391–720)a | 135b (29–333) | 279.8b (41.6–441.5) |
| Identified carrier newborns (n = 9) | 0.0064 (0.0009–0.0234) | 175 (101–728)a,c | 1,462 (202–7,889) | 0.4 (0–3.5)a |
| Unaffected newborns (n = 61) | 0.0099 (0.0005–0.0402) | 43 (29–165)a | 1,573 (137–10,641) | 2.9 (0–21.0)a |
| Cholestasis newborns (n = 15) | 0.0013 (0.0004–0.0035) | 49 (30–82)a | 7,800 (2,203–17,621) | 6.5 (0–6.5)a |
| PBD-ZSD adults/children (n = 10) | 0.120 (0.0100–0.4070) | Not determined | 318 (25–1,076) | 4.6 (0–8.5)a |
Data are expressed as mean (range of results) for m/z 75. Bold type indicates the 5β-cholestane-25-tetrol-glucuronide/tCDCA ratio and 7α12αC4 that are provided in Fig. 2B and C, respectively.
Outside validated linear analytical measurable range.
For one CTX-positive newborn sample, the mean calculated tCDCA concentration was 262 ng/ml (from n = 3 replicate analyses), with a resultant mean 5β-cholestane-25-tetrol-glucuronide/tCDCA ratio of 0.4546 (RSD 29.9%, n = 3). The mean 5β-cholestane-25-tetrol-glucuronide concentration for this sample was 492 ng/ml (RSD 9.7%, n = 3) and mean 7α12αC4 concentration was 46.5 ng/ml (14.5%, n = 3).
All non-CTX samples were <250 ng/ml 5β-cholestane-25-tetrol-glucuronide except one carrier cholestasis sample with a 5β-cholestane-25-tetrol-glucuronide value of 728 ng/ml.