Table. Clinical Subgroups Among the Cohort.
| Clinical Group | No. of Index Patients | No. (%) of Patients | ||||||
|---|---|---|---|---|---|---|---|---|
| Age at Onset <25 y | Age at Onset >40 y | Consanguinity | Very Probable or Definite Diagnosis | Very Probable or Definite Diagnosis When Age at Onset <25 y | Very Probable or Definite Diagnosis When Age at Onset >40 y | Possible Diagnosis | ||
| AOA-like phenotype (increased α-fetoprotein level, low albumin level, ocular apraxia) | 17 | 15 (88.2) | 1 (5.9) | 7 (41.2) | 6 (35.3) | 6 (35.3) | 0 | 2 (11.8) |
| Late complex (MSA-like, parkinsonism, not pyramidal) | 30 | 0 | 20 (66.7) | 7 (23.3) | 3 (10.0) | 0 | 0 | 1 (3.3) |
| Metabolic (mitochondrial features, white matter changes) | 70 | 45 (64.3) | 6 (8.6) | 24 (34.3) | 16 (22.9) | 10 (14.3) | 0 | 2 (2.9) |
| Pure (only cerebellar signs, slow progression) | 62 | 20 (32.3) | 13 (21.0) | 19 (30.6) | 9 (14.5) | 5 (8.1) | 0 | 6 (9.7) |
| Sensory ataxia (FRDA/PolG-like) | 19 | 9 (47.4) | 8 (42.1) | 8 (42.1) | 2 (10.5) | 2 (10.5) | 0 | 2 (10.5) |
| Spastic ataxia (cerebellar and pyramidal signs) | 100 | 42 (42.0) | 15 (15.0) | 36 (36.0) | 35 (35.0) | 18 (18.0) | 4 (4.0) | 6 (6.0) |
| Alla | 298 | 131 (44.0) | 63 (21.1) | 101 (33.9) | 72 (22.6)b | 41 (31.3) | 4 (6.4) | 19 (5.9) |
Abbreviations: AOA, cerebellar ataxia with oculomotor apraxia; FRDA, Friedreich ataxia; MSA, multisystemic atrophy; PolG, polymerase gamma.
a
Includes the 298 patients for whom complete clinical information was available.
b
Includes 1 patient with known SPG7 mutations lacking sufficient clinical information for classification.