Table 2.
Population characteristics by 10-year birth cohort including vital status, age at last encounter, and timing and mode of achondroplasia diagnosis.
| Characteristic | Birth decadea | |||||
|---|---|---|---|---|---|---|
| Before 1980 | 1980s | 1990s | 2000s | After 2010 | Total | |
| Population distribution, n | ||||||
| PAC | 234 | 231 | 314 | 356 | 239 | 1,374 |
| Active | 29 | 25 | 66 | 177 | 199 | 496 |
| Deceased | 15 | 3 | 2 | 0 | 0 | 20 |
| Age at last encounter, years | ||||||
| Mean | 34.9 | 17.7 | 14.8 | 9.7 | 3.4 | 15.4 |
| Range | 0.3-79.7 | 0.5-36.9 | 0-27.3 | 0.4-17.3 | 0.0-7.4 | 0.0-79.7 |
| Median (IQR) | 36.6 (17.8, 50.0) | 17.4 (9.9, 26.1) | 16.5 (9.9, 20.1) | 9.7 (7.1, 12.3) | 3.2 (1.9, 4.9) | 11.9 (5.6, 19.7) |
| Timing of diagnosis, n (%) | ||||||
| Prenatal | 0 (0) | 13 (5.6) | 53 (16.9) | 73 (20.5) | 76 (31.8) | 215 (15.6) |
| At birth | 40 (17.1) | 64 (27.7) | 72 (22.9) | 100 (28.1) | 67 (28.0) | 343 (25.0) |
| 24 hours–1 month | 16 (6.8) | 42 (18.2) | 51 (16.2) | 74 (20.8) | 39 (16.4) | 222 (16.2) |
| >1 month | 51 (21.8) | 39 (16.9) | 86 (27.4) | 80 (22.5) | 45 (18.8) | 301 (21.9) |
| Unknown | 127 (54.3) | 73 (31.6) | 52 (16.6) | 29 (8.1) | 12 (5.0) | 293 (21.3) |
| Mode of diagnosis,b n (%) | ||||||
| Molecular only | 1 (0.4) | 2 (0.9) | 10 (3.2) | 17 (4.8) | 19 (7.9) | 49 (3.6) |
| Clinicalc ± molecular | 85 (36.3) | 138 (59.7) | 239 (76.1) | 315 (88.5) | 213 (89.1) | 990 (72.1) |
| Unknown | 148 (63.3) | 91 (39.4) | 65 (20.7) | 24 (6.7) | 7 (3.0) | 335 (24.3) |
IQR interquartile range, PAC primary achondroplasia cohort.
aBirth decade: before 1980 = before 1 January 1980; 1980s = 1 January 1980–31 December 1989; 1990s = January 1990–31 December 1999; 2000s = 1 January 2000–31 December 2009; after 2010 = including and after 1 January 2010.
bSubjects presented by decade of birth, but diagnosis made at any time since birth. Unknown mode of diagnosis represents missing records and/or loss to follow-up such that the precise method of clinical diagnosis cannot be confirmed.
cClinical diagnosis includes physical exam, radiographs, ultrasound, family history.