Table 1.
Comparison of Thiemann disease and FDAB
| Thiemann disease | Familial Digital Arthropathy and Brachydactyly (FDAB) | |
|---|---|---|
| Gender |
M–F ratio is 1:1.1 (9 males, 10 females, 17 different families) |
M–F ratio is 1:1.1 (12 males, 13 females, 4 different families) |
| Age of onset | 8 years −40 years (median age = 24 years) | First decade, earliest reported age was 10 years. |
| Pattern of inheritance /genetic etiology | Autosomal dominant/ unknown | Autosomal dominant/TRPV4 variants |
| Clinical features | ||
| Pain | 73% (14/19), usually mild. | Prominent feature |
| Swelling | 75% (15/20) | Prominent feature |
| Joint movement limitation | 73% (14/20) | Present |
| Symmetrical | 85% (17/20) | Prominent feature |
| Radiological features | ||
| Affected hand joints |
95% (19/20): PIPs are more severely affected than DIPs o PIPS 95% (19/20) o DIPs 40% (8/20) o MCPs 20% (4/20) |
Constant involvement of PIPs, DIPs and MCPs. (DIPs were more severely affected than PIPs) |
| Affected feet joints | 20% (4/20)- MTPs | By adulthood, all MTPs are affected |
| Flattening | 35% (7/20) | Prominent feature |
| Irregularities | 45% (9/20) | Prominent feature |
| Short phalanges | 25% (5/20) | Prominent feature (progressive) |
| Broadening | 15% (3/20) | Present |
| Joint space reduction |
40% (8/20) o PIPs (8/20) o DIPs (3/20) |
Present (in adulthood) |
| Subchondral cysts | 5% (1/20) | Present |
| Fragmentation | 35% (7/20) | Not reported |
| Lateral deviation | 5% (1/20)- ulnar | Prominent feature (Radial>ulnar) |
M male, F female, PIPs proximal interphalangeal joints, DIPs distal interphalangeal joints, MCPs metacarpophalangeal joints, MTPs metatarsophalangeal joint