Table 1.
Descriptive statistics PKU, and ‘low–high’ groups
| PKU = 21 | Low–low = 3a | Low–high = 11 | High–high = 7 | |
|---|---|---|---|---|
| Mean age T1 ± SD (range) | 10.5 ± 2.0 (6.9–13.7) | 11.0 ± 2.3 (9.3–13.6) | 10.7 ± 2.1 (6.9–13.7) | 9.9 ± 1.7 (7.0–12.4) |
| Mean age T2 ± SD (range) | 25.8 ± 2.3 (21.0–30.5) | 26.6 ± 2.5 (23.9–28.7) | 25.7 ± 2.8 (21.0–30.5) | 25.7 ± 1.7 (23.0–28.8) |
| Gender (male:female) | 6:15 | 0:3 | 5:6 | 1:6 |
| Socio-economic status: income | 7 Above average | Average | 5 Above average | 2 Above average |
| Socio-economic status: education | 14 Higher education | 3 Higher education | 7 Higher education | 4 Higher education |
| IQ | 102 ± 13 (71–120) | 103 ± 14 (88–115) | 103 ± 9 (92–120) | 101 ± 18 (71–120) |
| Diagnostic Phe measurement | 1300 ± 925 (120–3151) | 205 ± 107 (120–325) | 1252 ± 805 (450–3053) | 1844 ± 904 (750–3151) |
| Biochemical PKU phenotype | 4 HPA; 8 mild PKU; 9 classical PKU | 3 HPA | 1 HPA; 6 mild PKU; 4 classical PKU | 2 mild PKU; 5 classical PKU |
| BH4 responsive | 5 BH4 responsive | 2 BH4 responsive | 2 BH4 responsive | 1 BH4 responsive |
| Concurrent Phe T1 ± SD (range) | 346 ± 204 (30–860) | 308 (2 missing) | 257 ± 157 (30–475) | 491 ± 211 (245–860) |
| IDC T1 ± SD (range) | 315 ± 92 (192–548) | 326 ± 53 (294–388) | 252 ± 42 (192–327) | 409 ± 84 (320–548) |
| Concurrent Phe T2 ± SD (range) | 719 ± 351 (259–1550) | 357 ± 87 (259–427) | 807 ± 403 (336–1550) | 735 ± 241 (345–1000) |
| IDC T2 ± SD (range) | 464 ± 138 (276–743) | 291 ± 15 (276–306) | 424 ± 79 (322–547) | 602 ± 112 (446–743) |
| IDC difference score (IDC2 minus IDC1) | 149 ± 120 (−82–330) | −35 ± −41 (−82 to −6) | 172 ± 93 (52–322) | 194 ± 112 (−6–330) |
| Phe 0–12 years ± SD (range) | 330 ± 91 (219–581) | 308 ± 35 (286–348) | 270 ± 40 (219–331) | 434 ± 71 (380–581) |
| Phe 13–17 years ± SD (range) | 533 ± 246 (267–1069) | 293 ± 30 (268–326) | 475 ± 172 (272–764) | 728 ± 269 (267–1069) |
| Phe >18 years ± SD (range) | 651 ± 258 (226–1105) | 253 ± 23 (226–267) | 658 ± 202 (465–1068) | 809 ± 211 (528–1105) |
BH4 tetrahydrobiopterin, IDC index of dietary control, PKU phenotype based on diagnostic Phe measurement, HPA hyperphenylalaninemia, Phe 120–600 µmol/L, mild PKU Phe 600–1200 µmol/L, classical PKU Phe >1200 µmol/L
aThe low–low group was excluded from statistical analyses because the sample size was too small