Archives for March 2009

Potential efficacy of enzyme replacement and substrate reduction therapy in three siblings with Gaucher disease type III.
J Inherit Metab Dis. 2008 Dec;31(6):745-52

Authors: Cox-Brinkman J, van Breemen MJ, van Maldegem BT, Bour L, Donker WE, Hollak CE, Wijburg FA, Aerts JM

We report three siblings with Gaucher disease type III, born between 1992 and 2004. During this period, new developments resulted in different potential therapies, changing clinical practice. The two eldest siblings received enzyme replacement therapy (ERT) from the age of 24 and 5 months respectively, later followed by an increase in dosage. ERT was combined with substrate reduction therapy (SRT) from the ages of 12 and 8 years, respectively. In the youngest sibling the combination of high-dose ERT and SRT was given from the age of 5 months. The two eldest siblings showed significant neurological impairment from the age of 1.5 years, starting with a convergent strabismus and partial oculomotor apraxia, followed by cognitive decline and an abnormal EEG and BAER. In contrast, the neurological development in the youngest sibling is almost completely normal.  At the age of 3 years, cognitive development, EEG and BAER are all normal. Disturbed saccadic eye movements, which were already present at the start of therapy, remained stable. In addition to the clinical efficacy, we report on the biochemical response to therapy.

Based on our results, the combination of high-dose ERT and SRT should be considered as a possible therapeutic approach for GD III, especially if started at a young age. Further follow-up studies are necessary to explore the long-term therapeutic effects.

PMID: 18850301 [PubMed – in process]

Spectrum of parkinsonian manifestations associated with glucocerebrosidase mutations
Arch Neurol. 2008 Oct;65(10):1353-7

Authors: Goker-Alpan O, Lopez G, Vithayathil J, Davis J, Hallett M, Sidransky E

BACKGROUND: Mutations in the glucocerebrosidase gene (GBA) result in Gaucher disease and can be associated with a phenotype characterized by adult-onset progressive neurologic deterioration and parkinsonism.

OBJECTIVE: To define the clinical and neurologic spectrum of parkinsonian manifestations associated with GBA mutations. Design, Setting, and Patients A prospective case series of 10 patients (7 men and 3 women) with parkinsonism and GBA mutations evaluated at the National Institutes of Health Clinical Center.

MAIN OUTCOME MEASURES: The GBA genotypes were identified by means of DNA sequencing. Tests evaluating neurologic, motor, cognitive, ocular, and olfactory functions were performed and the results were analyzed by a single team.

RESULTS: Genotyping identified GBA mutations N370S, L444P, and c.84dupG and recombinant alleles. The mean age at onset of parkinsonian manifestations was 49 years (range, 39-65 years), disease duration was 7.8 years (range, 1.2-16.0 years), and Unified Parkinson Disease Rating Scale part III score was 26.3 (range, 13-38). Half of the patients reported cognitive changes later in the disease course. Six patients were diagnosed as having Parkinson disease, 3 as having Lewy body dementia, and 1 as having a “Parkinson plus” syndrome. The most frequent nonmotor finding was olfactory dysfunction. Atypical manifestations included myoclonus, electroencephalographic abnormalities, and seizures.

CONCLUSIONS: In the homozygous and heterozygous states, GBA mutations are associated with a spectrum of parkinsonian phenotypes ranging from Parkinson disease, mostly of the akinetic type, to a less common phenotype characteristic of Lewy body dementia.

PMID: 18852351 [PubMed – indexed for MEDLINE]

Diltiazem, a L-type Ca(2+) channel blocker, also acts as a pharmacological chaperone in Gaucher patient cells.
Mol Genet Metab. 2009 Jan 21;

Authors: Rigat B, Mahuran D

Recently, inhibition of L-type Ca(2+) channels, using either Diltiazem or Verapamil, has been reported to partially restore mutant glucocerebrosidase activity in cells from patients with Gaucher disease homozygous for the N370S or L444P alleles, as well as cells from patients with two other lysosomal storage diseases. It was hypothesized that these drugs act on the endoplasmic reticulum, increasing its folding efficiency, inhibited due to altered calcium homeostasis. Several other laboratories have reported that cells carrying either the N370S or the F213I alleles are amenable to enzyme enhancement therapy with pharmacological chaperones, whereas cells homozygous for L444P respond poorly. We found that Verapamil treatment does not enhance mutant enzyme activity in any of the cell lines tested, while Diltiazem moderately increases activity in normal cells, and in N370S/N370S and F213I/L444P, but not in L444P/L444P Gaucher cells, or in either of two adult Tay-Sachs disease cell lines.

Since the mode of action of pharmacological chaperones and Diltiazem are believed to be different, we examined the possibility that they could act in concert. Diltiazem co-administered with known chaperones failed to increase enzyme activities above that reached by chaperone-treatment alone in any of the patient cell lines. Thus, we re-examined the possibility that Diltiazem acts as a pharmacological chaperone.

We found that, at the acidic pH of lysosomes, Diltiazem was not an inhibitor, nor did its presence increase the heat stability of glucocerebrosidase. However, at neutral pH, found in the endoplasmic reticulum, Diltiazem exhibited both of these properties. Thus Diltiazem exhibits the biochemical characteristics of a glucocerebrosidase pharmacological chaperone.

PMID: 19167257 [PubMed – as supplied by publisher]

Randomized, controlled trial of miglustat in Gaucher’s disease type 3.
Ann Neurol. 2008 Nov;64(5):514-22

Authors: Schiffmann R, Fitzgibbon EJ, Harris C, DeVile C, Davies EH, Abel L, van Schaik IN, Benko W, Timmons M, Ries M, Vellodi A

OBJECTIVE: To evaluate the efficacy and safety of miglustat, concomitant with enzyme replacement therapy (ERT), in patients with Gaucher’s disease type 3 (GD3).

METHODS: This 24-month, phase II, open-label clinical trial of miglustat in GD3 was conducted in two phases. During the initial 12 months, patients were randomized 2:1 to receive miglustat or “no miglustat treatment.” The randomized phase was followed by an optional 12-month extension phase in which all patients received miglustat. All patients received ERT during the 24-month period. The primary efficacy end points were change from baseline to months 12 and 24 in vertical saccadic eye movement velocity as determined by the peak amplitude versus amplitude regression line slope. Secondary end points included changes in neurological and neuropsychological assessments, pulmonary function tests, liver and spleen organ volumes, hematological and clinical laboratory assessments, and safety evaluations.

RESULTS: Thirty patients were enrolled, of whom 21 were randomized to miglustat and 9 to “no miglustat treatment.” Twenty-eight patients entered the 12-month extension phase. No significant between-group differences in vertical saccadic eye movement velocity or in the other neurological or neuropsychological evaluations were observed. Organ volumes and hematological parameters remained stable in both treatment groups, but improvement in pulmonary function and decrease of chitotriosidase levels were observed with miglustat compared with patients receiving ERT alone.

INTERPRETATION:   Miglustat does not appear to have significant benefits on the neurological manifestations of GD3. However, miglustat may have positive effects on systemic disease (pulmonary function and chitotriosidase activity) in addition to ERT in patients with GD3.

PMID: 19067373 [PubMed – indexed for MEDLINE]