Ari Zimran

Late Onset Tay- Sachs disease (LOTS) is a rare neurodegenerative lysosomal storage disease which results from mutations in the gene encoding the α subunit (HEXA) of β-hexosaminidase enzyme (HexA). At the present time, no effective treatment exists for LOTS and other neurodegenerative diseases involving the central nerve system (CNS). Pyrimethamine (PMT) was previously shown to act as a HexA chaperone in human fibroblasts in vitro carrying some (e.g., αG269S), but not all LOTS-related mutations. The present study assessed the effect of cyclic, low dose and long term pyrimethamine treatment on HexA in subjects with LOTS. In an open label trial in 4 LOTS patients, PMT was initiated at an average daily dose of ~2.7 mg and administered cyclically guided by blood lymphocyte HexA activity for a mean duration of 82.8 (±22.5; SD) weeks (~1.5 year). HexA activity rose in all subjects, with a mean peak increase of 2.24 folds (±0.52; SD) over baseline activity (range 1.87-3). The mean treatment time required to attain this peak was of 15.7 (±4.8; SD) weeks. Following increase in activity, HexA gradually declined with the continued use of PMT, which was then stopped, resulting in the return of HexA activity to baseline. A second cycle of PMT treatment was then initiated, resulting again in an increase in HexA activity. Three of the patients experienced a measurable neuropsychiatric deterioration whereas one subject remained entirely stable. Cyclic low dose of PMT can increase HexA activity in LOTS patients. However, the observed increase is repeatedly transient and not associated with discernible beneficial neurological or psychiatric effects.

The non-neuronopathic form Gaucher disease, the most prevalent lysosomal storage disorder, is marked by tremendous phenotypic heterogeneity; cardio-pulmonary involvement is distinctly rare except in the most severely affected patients. With the advent of enzyme replacement therapy, most symptomatic patients will not suffer from lung disease. However, because of concern about pulmonary hypertension among adult patients exposed to enzyme replacement therapy, echocardiography has been recommended as an early warning system for routine follow-up of all patients, including children. The purpose of this study was to review the results of more than a decade of echocardiographic findings in children followed semi-annually in a large referral clinic in order to ascertain whether echocardiography as an early signal of pulmonary hypertension in children is appropriate. 330 echocardiographic examinations were performed in 71 children (276 patient follow-up years). Only four patients receiving enzyme therapy each had a single abnormal examination that upon repeat examination six months later reverted to within normal limits. There were no abnormal results among the untreated patients. Therefore, we feel comfortable with rescinding our recommendation with regard to routine echocardiographic examinations in children. At the present time we believe that a baseline examination to rule out abnormalities would be sufficient.

Background: Patients with symptomatic Gaucher's disease sometimes have non-specific symptoms (such as general malaise with widespread musculoskeletal pains) that respond poorly to enzyme replacement treatment. These may indicate fibromyalgia syndrome; if so, other therapeutic options might be more appropriate. Aim: To identify patients with Gaucher's disease for whom fibromyalgia-specific therapy may be therapeutic. Design: Questionnaire-based survey. Methods: Adult patients (n = 109) with non-neuronopathic Gaucher's disease and adult healthy controls (n = 108) completed health-related questionnaires including the Fibromyalgia Impact Questionnaire, and underwent testing with a dolorimeter to ascertain sensitivity at 22 tender points. Results: Six patients, but no controls, met the criteria for fibromyalgia. Patients with fibromyalgia had a significantly greater incidence of co-morbidities (p = 0.014) relative to other patients with Gaucher's disease; four suffered from bone involvement and were receiving enzyme therapy, but two were untreated. Discussion: The presence of fibromyalgia-specific trigger points may result from multiple aetiologies, or may be an independently-sorting predisposition. Our findings cannot distinguish between these possibilities, but if fibromyalgia were the cause, enzyme replacement therapy would be expensive and inappropriate.

Gaucher disease is the most common lysosomal storage disease. Enzyme replacement therapy engenders improvement in hematological and visceral parameters; however, improvement in bone density (BMD) with treatment has not been confirmed. This study presents follow-up of BMD in the first ten patients in Israel treated with low-dose recombinant enzyme for up to 108 months. BMD at femoral neck and lumbar spine was determined by dual-energy X-ray absorptiometry (DEXA) at the start of the trial, after 3–6 months, after 18–24 months, and at the most recent follow-up. BMD in all patients was very low at onset and never normalized. There was a decrease in BMD in all patients at 3–6 months. Older patients (four women, two men; >30 years of age) showed some improvement in BMD during treatment. Younger patients (four females; 18–23 years of age) did not show a statistically significant improvement. These findings might reflect the failure of patients with Gaucher disease to achieve expected peak bone density at appropriate chronological milestones despite treatment. Nonetheless, the z-scores of the older patients were better than those of the younger patients, implying some catch-up period. Yet, some patients with Gaucher disease evince rapid onset of osteoporosis in early adulthood. Enzyme treatment per se, as well as attendant improved well-being and increased physical activity, may induce amelioration in BMD at this later stage. One may consider adding anti-osteoporosis therapy in young adults to induce earlier “catch up” to peak bone mass, and then enzyme replacement in later adulthood to prevent decrements in bone mass related to Gaucher cell infiltration.