Table 1.
Clinical findings and further investigations in PRPS1 Gln277Pro mutation carriers
| Subject | II.2 | II.1 | I.2 |
|---|---|---|---|
| Gender |
m |
f |
f |
| Phenotypic cluster |
CMTX5/Arts |
DFN2 |
None |
| Current age |
36 |
42 |
66 |
| Age of onset first symptom |
Congenital, hearing loss |
Congenital, hearing loss |
None |
|
Neurological | |||
| Mental retardation |
(+) progressive aggressive, childish behavior, starting at age 18 |
- |
- |
| Ataxia (age of onset) |
+, 30 years |
- |
- |
| Severity of ataxia (SARA score) |
14 out of 40 |
1 out of 40 |
0 out of 40 |
| Delayed motor development |
- |
- |
- |
| Loss of deep tendon reflexes |
+ |
- |
- |
| Hearing loss (age of onset) |
+, congenital |
+, congenital |
|
| Optic atrophy (age of onset) |
12 |
-- |
- |
|
Uric acid overproduction | |||
| Gout |
- |
- |
- |
| Kidney stones |
- |
- |
- |
| Renal failure |
- |
- |
- |
| Serum uric acid (ref 3.4-7.0 mg/dl) |
4.3 mg/dl |
4.4 mg/dl |
4.2 mg/dl |
|
Hematopoetic | |||
| Recurrent infections |
(+), only from age 6 to 8 years |
- |
- |
| Anemia |
- |
- |
- |
|
Other | |||
| Short stature |
- |
- |
- |
| Self-injury |
- |
- |
- |
| Early death |
- |
- |
- |
|
Lab, electrophysiology and MRI investigations | |||
| Nerve conduction studies |
|
|
|
| -Sensory nerve conduction |
Sur: no SNAP; Rad: no SNAP |
Sur: normal, Rad: normal |
n.d. |
| Sural or radial nerve | |||
| -Motor nerve conduction |
Tib: borderline MNCV (40 m/s; ref > 40 m/s); Uln: reduced CMAP (2.1 mV; ref: > 4 mV); reduced MNCV (36 m/s; ref: > 50 m/s) |
Tib: normal; Uln: normal |
|
| Tibial or ulnar nerve | |||
| MRI |
Mild cerebellar and parietal cortical atrophy |
Mild cerebellar and parietal cortical atrophy |
n.d. |
| Serum creatinkinase (ref <180 U/l) |
1168 U/l |
141U/l |
196 U/l |
| PRS-I enzyme activity (ref 0.41-1.46 nmol/(min.mg protein) | <0.005 nmol/(min.mg protein) | 0.1 nmol/(min.mg protein) | 1.04 nmol/(min.mg protein) |
This table was designed to show not only those clinical symptoms that are present, but also those that are absent in this index family, yet common in other PRPS1 patients. The features were selected and extended from de Brouwer et al., 2010 [6]. Legend: m, male; f, female; n.d., not done; ref, reference value; SARA, scale for the Assessment and Rating of Ataxia, reaching from 0 to 40, with higher scores indicating more severe ataxia; scores < 3 points are considered unspecific. Sur = sural; Rad = radial; Tib = tibial, Uln = ulnar; SNAP = sensory nerve action potential; SNCV = sensory nerve conduction velocity; CMAP = compound muscle action potential; MNCV = motor nerve conduction velocity; MRI, magnetic resonance imaging.