Methods: Four international experts weighted the SST domains usingnominal group technique to reach consensus. First, all domains were rankedaccording to the amount of morbidity each contributes to NGD severity.Based upon these rankings the experts assigned the range of scores, repre-senting the relative weights, for the clinical measurements within eachdomain. A Likert-like scale was used allowing for a maximum range of 0–10.

Results: Experts ranked the epilepsy domain as contributing the mostto severity, followed by pyramidal, cognitive ability, extrapyramidal, cer-ebellar signs, swallowing, ataxia/gait, speech, kyphosis, ophthalmology,horizontal gaze palsy (HGT) (least). The attributed severity scores werelater supported in the individual domain scoring, identifying a maximumaverage score of 2.25 for the HGT domain and average scores of 9.25 forepilepsy and pyramidal domains. Overall consistency in scoring wasobserved in all domains except cerebellar signs and swallowing.

Conclusion: Assigned SST domain weights reflect the amount of mor-bidity each domain contributes to NGD severity. The SST will now bedeveloped to reflect this, and utilised for international cohort comparison,for the management of medical interventions, and as an endpoint in clin-ical studies.

doi:10.1016/j.ymgme.2007.10.032

21. Recent developments on lysosomal storage disorder activities at the

Centers for Disease Control and Prevention

Victor De Jesus, Robert Vogt, W. Harry Hannon, Centers for Disease

Control and Prevention, Atlanta, GA, USA

Lysosomal storage disorders (LSDs) are a group of over 40 genetic dis-orders caused by inborn errors of metabolism. Individuals with LSDs arecharacterized by low activities of particular enzymes found in the lysosome,resulting in the accumulation of molecules that are meant to be processed bythese enzymes. While lysosomal storage disorders are each rare diseases, as agroup they are estimated to affect 1 in 7700 to 1 in 10,000 live births world-wide. Most LSDs are progressive and life threatening; if left untreated, theycan cause physical debilitation, mental retardation and early death.

Newborn screening for LSDs using dried blood spots and tandem massspectrometry is an emerging field in clinical chemistry, and currently thereis fervent debate over the launch of LSD screening on a population-basedbasis. At present, New York is the only state performing newborn screen-ing for one disorder, Krabbe disease. Other states (Illinois, Washington)will conduct population-based pilot studies using tandem mass spectrom-etry. With this in mind, the Newborn Screening Translational ResearchInitiative (NSTRI), in collaboration with the Centers for Disease Controland Prevention (CDC) and the CDC Foundation, has established state,industry and international partnerships to address newborn screeningfor lysosomal storage disorders. Recent developments include the distribu-tion of reagents to newborn screening laboratories performing tandemmass spectrometry-based LSD screening, and the creation of qualityassurance materials for laboratories performing newborn dried blood spotscreening for LSDs.

doi:10.1016/j.ymgme.2007.10.033

22. Initial experience with intrathecal recombinant human a-L-iduronidase

for spinal cord compression in two mucopolysaccharidosis I patients

Patricia Dickson a, David Naylor b, Anton Mlikotic c, Alla Victoroff a,

Agnes Chen b, Merry Passage a, Steven Le a, a Division of Medical

Genetics, LA Biomed at Harbor-UCLA, Torrance, CA, Torrance, CA,

USA, b Department of Neurology, Harbor-UCLA Medical Center,

Torrance, CA, USA, c Division of Neuroradiology, Harbor-UCLA

Medical Center, Torrance, CA, USA

Intrathecal recombinant human a-L-iduronidase (IT rhIDU) led toimprovements in signs and symptoms of spinal cord compression in one

adult MPS I patient (Muqoz-Rojas et al., in press). We treated threepatients 13–31 year with MPS I and spinal cord compression with 3–7doses of 1.74 mg IT rhIDU at 1–3 month intervals. Two received ITrhIDU as part of an ongoing clinical trial. Subjective improvement wasnoted in 3/3 patients in at least three major CNS symptoms. Theseincluded ability to move legs, pain in the legs, back and/or neck, blad-der/bowel incontinence, restless legs, numbness/tingling of the feet, fati-gue, and reduced hand use. Improvement in neurologic examinationoccurred in 3/3 patients: in pain/temperature asymmetries, strength, deeptendon reflexes, and range of motion. One patient gained independence insome aspects of self-care, resulting in a 9-point improvement in FunctionalIndependence Measure (FIM) score (11%, from 82 to the maximum scoreof 91). Adverse events with >1 occurrence included headache, pain in but-tocks, back, and neck, pneumonia, low platelets, anemia, and sore throat.One subject developed CSF pleocytosis which responded to a short courseof oral steroids. Two subjects with hydrocephalus and implanted shunts atstudy entry developed apparently transient elevated CSF opening pres-sure. One serious adverse event occurred (pneumonia). MPS I patients tol-erate IT rhIDU well and have experienced improvement in signs andsymptoms of spinal cord compression. Further study is ongoing.

doi:10.1016/j.ymgme.2007.10.034

23. Pharmacological chaperone treatment for Pompe disease

Hung Do, John Flanagan, Xiaoyang Wu, Allan Powe, Richie Khana,

Rebecca Soska, Wei Liang, Elfrida Benjamin, David Palling, Sheela

Sitaraman, Brandon Wustman, Ken Valenzano, David Lockhart, Amicus

Therapeutics, Inc., Cranbury, NJ, USA

Pompe disease is caused by mutations in the enzyme acid alpha-gluco-sidase (GAA) that alter lysosomal glycogen metabolism. The disease ischaracterized by progressive skeletal muscle weakness, reduced cardiacfunction, respiratory insufficiency, and CNS impairment. We are develop-ing small molecule pharmacological chaperones that can increase cellularactivity by selectively binding and stabilizing the target protein. Here, weshow that the pharmacological chaperone AT2220 (1-deoxynojirimycinHCl) significantly increased enzyme activity for several GAA missensemutants in patient-derived fibroblasts and improved the proteolytic pro-cessing of mutant forms of GAA. The effects of AT2220 on GAA with dif-ferent missense mutations were further characterized using transientexpression in COS-7 cells, and multiple responsive mutations wereidentified.

We subsequently evaluated AT2220 in wild type mice and found thatthe compound significantly increased GAA activity in multiple tissuesaffected in Pompe disease, including heart, gastronemius, soleus, tongue,diaphragm and brain. Similar results were also observed in normal ratsand cynomologus monkeys. These results suggest that AT2220 mayincrease enzyme activity for the common IVS1 splice variant which pro-duces low levels of wild type GAA.

AT2220 was evaluated in normal subjects (up to 1000 mg/day for14 days) in a Phase 1 clinical trial. The drug was well-tolerated and nodrug-related serious adverse events were observed. Collectively, these dataindicate that AT2220 merits further evaluation as a treatment for patientswith Pompe disease.

doi:10.1016/j.ymgme.2007.10.035

24. Data collection tools for compiling accurate health histories

Colleen Doyen, University of Minnesota, Minneapolis, MN, United States

Background: The University of Minnesota began submitting patientinformation to the Genzyme MPS I Registry in June 2005. This Registryis an observational database that tracks natural history and outcomes ofpatients with MPS I. One of the primary objectives of the Registry is tocharacterize and describe the MPS I patient population as a whole.

Abstracts / Molecular Genetics and Metabolism 93 (2008) S14–S46 S19

Hypothesis: The development of a systematic format for data collec-tion will assist in acquiring comprehensive and complete history and out-come data for the MPS I Genzyme Registry.

Methods: At the University of Minnesota Gene Therapy Center, formswere created to help gather information from the annual visits for patientswith MPS I, Pompey, Fabry, and Gaucher diseases. Information is gath-ered with the use of a specially designed form that the patient’s familycompletes. This form requests specific information that is required forthe Genzyme Registry. The fields are event, yes/no, date, and circle thecorrect response.

Results: When the patient information is arranged with the use of thisform, data was easier to enter into the MPS I Registry and increased con-fidence and veracity in the completeness of the information entered. Thepatient information was also accessible for use on other research projects.Registry follow-up information was easily gathered because the changesfrom the last visit were noted on the follow-up form. We also found thisform helps to facilitate dialogue between the practitioner and the family,and assist with documentation of the many physical issues for thesechildren.

Conclusions: With the follow-up data form, we have been able togather information from patients’ families concerning visits to other facil-ities (opticians, ENT specialists, etc.) during the past year. This organiza-tional set of tools has allowed University of Minnesota to contribute to theMPS I Registry and more importantly, to assist in the compiling a com-plete picture of health for each patient.

doi:10.1016/j.ymgme.2007.10.036

25. Biochemical characterization of the N370S glucocerebrosidase mutant:

Implications for chaperone therapy

Tim Edmunds, Heather Hughes, Julie Jaworski, Lori Rulli, David Reczeck,

Scott VanPatten, Genzyme Corporation, Framingham, MA, USA

It has been proposed that the N370S mutation, the most prevalentmutation causing Gaucher disease, is a folding mutation that leads toincreased degradation in the endoplasmic reticulum resulting in decreasedlysosomal enzyme levels. This has led to the proposed use of competitiveinhibitors as ‘‘pharmacological chaperones’’ to prevent proteolysis andpromote trafficking to the lysosome.

To test this hypothesis we expressed, purified and characterized recom-binant N370S mutant beta-glucocerebrosidase. The purified protein hasreduced enzymatic activity, increased lysosomal stability and binds nor-mally to LIMP-2, the protein responsible for the intracellular transportof glucocerebrosidase to the lysosome. Given these properties we exam-ined in more detail the mechanism by which competitive inhibitorsincrease cellular levels of the mutant protein. To eliminate effects due tostabilization/transport we studied the effect of competitive inhibitors onthe intracellular stability of recombinant beta-glucocerebrosidase adminis-tered to macrophages in culture. The presence of competitive inhibitorsincreased the lysosomal half-life of beta-glucocerebrosidase up to three-fold. The increase in intracellular half-life was shown to be a result ofincreased resistance to proteolysis by cathepsins.

These data suggest that the increased protein levels observed in thepresence of competitive inhibitors is due to reduced lysosomal degradationrather than an effect on trafficking. Since stabilization is dependent onbinding and therefore inhibition of the enzyme these inhibitors are unli-kely to provide any therapeutic benefit.

doi:10.1016/j.ymgme.2007.10.037

26. Molecular analysis of Turkish Gaucher disease patients

Serap Emre a, Figen G.E. Urakan b, Aysel Yuce b, Arnold Rolf c, Ronald

Scott d, Hasan Vzen b, a Department of Medical Biology, University of

Hacettepe, Ankara, Turkey, b Pediatric Gastroenterology, Hepatology and

Nutrition, University of Hacettepe, Ankara, Turkey, c Universitat Rostock,

Neurobiologisches Labor, Klinik fur Neurologie, d Children’s Hospital

Seattle, WA, USA

Introduction: Gaucher disease (GD) is the most frequent lysosomalglycolipid storage disorder due to autosomal recessive deficiency of acida-glucosidase and is characterized by the accumulation ofglucocerebroside.

Hypothesis: In this work we carried out molecular analysis of theglucocorebrosidase gene (GBA) in 66 unrelated patients and the allelic fre-quencies of gene mutations in Turkish patients are reported.

Methods: The diagnosis was based on clinical data including age ofonset, organomegaly, skeletal features, presence or absence of progressivecentral nervous system symptoms, as well as reduced cellular acid a-gluco-sidase activity. Forty patients were classified as type 1, 5 as type 2, 14 astype 3 and 7 as type 1 or type 3 because of very young age and short followup. DNAs of GD patients were isolated from peripheral leucocytes by theammonium acetate salting out procedure. Five DNA was screened for thecommon N370S , L444P, R463C and 84GG mutations. Exonic and mostintronic sequences of the GBA gene were PCR amplified in three frag-ments using primers designed to amplify selectively the gene and not thepseudogene, as described by Koprivica et al. Cycle sequencing was per-formed with the ABI PRISM Big Dye Terminator Cycle Sequencing Kitfollowing the manufacturer’s instructions and sequences were analyzedon the ABI PRISM 3130 DNA Analyzer.

Results and conclusions: In this study a total of 121 GBA mutantalleles (91.6%) were identified. The most frequent mutation was theL444P found in 50 alleles (37.8%). The second frequent mutation wasthe N370S occurring in 45 alleles (34.8%) and D409H was the third fre-quent mutation found in 5 alleles (4.3%). R463C was present in four alleles(3.5%). We did not detect mutation 84GG in our Turkish patients.Twonovel mutations (L296V and S356F) were detected with type 1 patients.303–305delCAC novel mutation was detected in a patient with indetermi-nate phenotype type 1 or type 3.

doi:10.1016/j.ymgme.2007.10.038

27. Nephropathy in Fabry disease: Baseline characteristics of 1262 patients

in the Fabry Registry

Christine Eng a, Alberto Ortiz b, Joco Oliveira c, Steven Waldek d, David

Warnock e, Bruno Cianciaruso f, Christoph Wanner g, a Molecular and

Human Genetics, Baylor College of Medicine, Houston, TX, USA,b Nephrology, Fundacion Jimenez Diaz, Madrid, Spain, c Nephrology and

Genetics, Hospital Sco Joco, Porto, Portugal, d Adult Inherited Metabolic

Diseases, Hope Hospital, Salford, United Kingdom, e Medicine, University

of Alabama at Birmingham, Birmingham, AL, United States, f Division of

Nephrology, University ‘‘Federico II’’ of Naples, Italy, g University of

Wurzburg, Division of Nephrology, University Hospital, Wurzburg,

Germany

Background: The spectrum of kidney involvement in Fabry disease hasnot been well defined, especially in female patients who may also demon-strate other disease manifestations.

Methods: We performed a cross-sectional retrospective analysis of nat-ural history data from the Fabry Registry (including estimated glomerularfiltration rate (eGFR), proteinuria, albuminuria, blood pressure) from 677females and 585 males with documented Fabry disease.

Results: Chronic kidney disease (CKD) with eGFR <60 ml/min/1.73 m2 was reported in 13% of females (age 20–82 years) and 28% ofmales (20–79 years). Proteinuria >300 mg/24 h was seen both in females(26%) and in males (43%) with CKD stage 1, and median values werehigher with more severe kidney dysfunction. 28% of females and 11% ofmales with eGFR <60 ml/min/1.73 m2 had proteinuria <300 mg/24 h.Among patients with eGFR 360 ml/min/1.73 m2 without overt proteinuria(n = 93), albuminuria >30 mg/24 h was found in 35% of the females and55% of the males. Systemic blood pressure was 3130/80 mmHg in 48%

S20 Abstracts / Molecular Genetics and Metabolism 93 (2008) S14–S46