Saccadic Impairments in Patients with the Norrbottnian Form of Gaucher's Disease Type 3.

BACKGROUND: Chronic neuronopathic Gaucher's disease type 3 (GD3) is relatively frequent in northern Sweden. Besides multiple other neurological symptoms, horizontal gaze palsy or oculomotor apraxia is common in GD3. OBJECTIVE: To characterize the saccades in patients with Norrbottnian GD3 with respect to their neurological and cognitive status using a computer-based eye-tracking technique. METHODS: Horizontal and vertical reflexive saccades as well as antisaccades of nine GD3 patients [4M/5F; 41.1 ± 11.0 years; modified severity scoring tool (mSST): 9.3 ± 5.4; Montreal Cognitive Assessment (MoCA): 24.0 ± 4.2] and age-matched controls were analyzed using EyeBrain T2, a head-mounted binocular eye tracker. Systematic clinical assessment included the mSST, a valid tool for monitoring the neurological progression in GD3 and MoCA. RESULTS: In Norrbottnian GD3 patients, gain, peak, and average velocity (107.5°/s ± 41.8 vs. 283.9°/s ± 17.0; p = 0.0009) of horizontal saccades were reduced compared to healthy controls (HCs). Regarding vertical saccades, only the average velocity of downward saccades was decreased (128.6°/s ± 63.4 vs. 244.1°/s ± 50.8; p = 0.004). Vertical and horizontal saccadic latencies were increased (294.3 ms ± 37.0 vs. 236.5 ms ± 22.4; p = 0.005) and the latency of horizontal reflexive saccades was correlated with the mSST score (R2 = 0.80; p = 0.003). The latency of antisaccades showed association to MoCA score (R2 = 0.70; p = 0.009). GD3 patients made more errors in the antisaccade task (41.5 ± 27.6% vs. 5.2 ± 5.8%; p = 0.005), and the error rate tended to correlate with the cognitive function measured in MoCA score (p = 0.06). CONCLUSION: The mean age of 41 years of our GD3 cohort reflects the increased life expectancy of patients in the Norrbottnian area compared to other GD3 cohorts. Marked impairment of horizontal saccades was evident in all patients, whereas vertical saccades showed distinct impairment of downward velocity. Latency of reflexive saccades was associated with the severity of neurological symptoms. Increased latency and error rate in the antisaccade task were linked to cognitive impairment. The assessment of saccades provides markers for neurological and neuropsychological involvement in Norrbottnian GD3.

Atypical cytomorphology of Gaucher cells is frequently seen in bone marrow smears from untreated patients with Gaucher disease type 1.

INTRODUCTION: Gaucher cells (GCs), the lipid-laden storage macrophages, are the pathologic hallmark of Gaucher disease (GD). They are typically 20-100 µm in diameter with eccentrically placed nuclei and cytoplasm with characteristic crinkles and striations. A few previous observations have indicated that sometimes GD patients may display morphology of GCs which is different from this classical description. The aim of our study was to explore the morphological polymorphism of GCs in patients with untreated GD type 1 (GD1). MATERIAL AND METHODS: May-Grünwald Giemsa stained bone marrow smears (BM-S) from 6 patients with sporadic GD1 were analysed; each patient sample consisted of two slides where all GCs and non-Gaucher cell macrophages were counted. We have defined for the study purposes and examined the following features of GCs which were considered as atypical: (1) foamy cytoplasm, (2) centrally placed nucleus, (3) cell diameter > 100 µm, (4) multinuclearity, (5) syncytial morphology, (6) unusually large cytoplasmic projections, and (7) apparent haemophagocytosis. RESULTS: All analysed patients showed 22-40% GCs with atypical cytomorphology (median 29%). The median number of atypical features of GCs was 10 per patient (range 6-13). Multinuclearity was the most common atypical feature of GCs, followed by erythrophagocytosis and foamy cytoplasm. There was a strong positive correlation between erythrophagocytosis and foamy cytoplasm in GCs (Spearman's rank correlation coefficient: 0.9). Although majority of atypical GCs had one atypical feature, there was a considerable amount of GCs presenting ≥ 2 atypical features. CONCLUSIONS: Untreated patients with GD1 often show a considerable proportion of GCs with atypical cytomorphology. The knowledge of possible atypical variant forms of GCs can contribute to a quicker and accurate diagnosis of GD, and minimize the risk for misdiagnosis. To the best of our knowledge, this is the first published report on atypical cytomorphology of GCs in untreated patients with GD1.

Impact of imiglucerase supply shortage on clinical and laboratory parameters in Norrbottnian patients with Gaucher disease type 3.

A viral contamination of the production plant producing imiglucerase (Cerezyme™) resulted in an unpredicted worldwide shortage of global supplies during 2009-2010. The aim of the study was to describe the effects of dose reduction of enzyme replacement therapy (ERT) in adults with Norrbottnian form of Gaucher disease type 3 (N-GD3). There were ten adults with N-GD3 treated with imiglucerase in the county of Norrbotten in June 2009. Analyzed variables included plasma chitotriosidase activity and concentration of CCL18/PARC, whole blood hemoglobin concentration (Hb) and platelet count (PLT), as well as patients' body weight, subjective complaints and health status measured by the EuroQoL-5D questionnaire. The median duration of ERT shortage lasted for 14 months (10-20 months). The median percentage reduction of imiglucerase dose was 36 % (26-59 %). Hb decreased in four patients, PLT decreased in three patients, chitotriosidase increased in three patients (max. +22 % of baseline), and CCL18/PARC increased in six patients (+14 % to +57 %). The body weight was moderately decreased in one patient. No new bone events were noted. Self-assessment of individual patient's health status was stable in all but one patient. Our results suggest that moderate reduction of ERT dosage lasting for relatively short period of time can lead to worsening in biomarkers of adults with N-GD3. However, this worsening is infrequently translated to clinical worsening of patients. It is possible that CCL18/PARC has a higher sensitivity than chitotriosidase in monitoring of ERT dosing in GD3.