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BIOCHEMICAL GENETICS
 

BIOCHEMICAL GENETICS

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    BIOCHEMICAL GENETICS BIOCHEMICAL GENETICS Document Transcript

    • POSTER PRESENTATIONS BIOCHEMICAL GENETICS 51 52 The Pompe Registry: Centralized Data Collection to Outline the Natural Sarcoidosis in type 1 Gaucher disease. B.G. Crissman1, J.A. Govert2, J.F. Course of Pompe Disease. B. Byrne1, A. van der Ploeg2, W. Mueller-Felber3, P. Mackey1, J.A. Sullivan1, P. Mistry3, P.S. Kishnani1. 1Department of Pediatrics, Kishnani4. 1Pediatric Cardiology, Univ Florida, Gainsville, FL; 2Sophia Childrens Duke University; 2Department of Medicine, Duke University; 3Department of Med- Hospital, Rotterdam, The Netherlands; 3Friedrich-Baur-Institut, Munich, Gemany; icine, Yale University. 4Department of Pediatrics,Duke University Medical Center, Durham, NC. Gaucher disease (GD) is an autosomal recessive, multisystemic disease due to Background: Pompe disease is a rare, progressive, and often fatal muscle disease widespread accumulation of glucosyceramide-laden macrophages. Disease manifes- that can be diagnosed in infants, children, and adults. The underlying pathology is a tations are believed to be mediated by systemic macrophage activation triggered by deficiency of acid alpha-glucosidase (GAA), a lysosomal enzyme that hydrolyzes accumulating glucosylceramide. Sarcoidosis is a multisystemic disorder of un- lysosomal glycogen. Pompe disease is an extremely heterogeneous disorder that var- known etiology that also involves systemic macrophage activation. We report a sib- ies with respect to age at onset, rate of disease progression, and extent of organ in- ling pair with type 1 GD (GD1), who developed sarcoidosis and its effect on the volvement. Due to the rarity of the disease, heterogeneity of symptoms, and multiple Gaucher phenotype. Patient A is a Caucasian male diagnosed with GD1 at age 8. He organ systems affected, the collection of longitudinal data requires a broad effort developed progressive hepatosplenomegaly and cytopenia but skeletal disease was across many physicians having patients with Pompe disease under their care. Meth- mild. Enzyme replacement therapy (ERT) was started at age 37, resulting in amelio- ods: In order to gain a better understanding of the natural course of Pompe disease, ration of organomegaly and cytopenia. At age 43, he presented with respiratory a centralized international Registry was developed to collect anonymous data on pa- symptoms and was found to have mediastinal, hilar lymphadenopathy and pulmo- tients with Pompe disease. The first submitted demographic data of enrolled patients nary nodules. Bone marrow aspirate showed Gaucher cells had cleared with ERT were analyzed in respect to geographic location, gender, ethnicity, residual enzyme and lymph node biopsy revealed multiple dense granulomas typical of sarcoidosis level, age of disease onset, and age of diagnosis.Results: As of December 3, 2004, and no Gaucher cells. ERT was continued and there was spontaneous regression of 27 patients have been enrolled in the registry by 8 centers across the globe (Bra- sarcoidosis. He was never treated with systemic corticosteroids. Patient B, full sister zil:10; Poland:7, Portugal:3; Italy: 5; US:2), 48% male and 52% female patients. of A, was diagnosed with GD1 at age 22. She underwent a splenectomy and devel- 60% are Caucasian, 7% are black, and the remainder are other or unknown. 8 of oped progressive hepatomegaly. ERT was administered between the ages of 32 and these patients have a sibling affected with Pompe disease. 6/27 (22%) of the enrolled 42. Shortly after discontinuation of ERT, she developed hilar lympadenopathy, a patients have infantile-onset disease (IO: symptom onset 1 year of age). The median nodular right lung infiltrate, ankle edema and subcutaneous nodules - biopsy showed age of IO diagnosis is 0.7 years (range: 0.38-1.45 years). 18/27 (67%) of the patients a perivascular lymphohistiocytic infiltrate consistent with cutaneous sarcoidosis. have late-onset disease (LO: symptom onset > 1 year of age). The median age of LO She was treated with a short course of steroids and during the subsequent 8 months diagnosis is 32.9 years (range: 2.36-45.83 years). The remaining 3 patients have un- all symptoms resolved spontaneously. Patient B recently resumed ERT. Patients A known age of onset of symptoms. Of the 12 patients with a known diagnostic assay and B are a remarkable sibpair with GD1 who developed sarcoidosis. We are not method, 4 utilized dried blood spot testing, 3 utilized leukocyte assays, 3 utilized fi- aware of a direct association, although both conditions involve macrophage activa- broblast assays, 1 utilized a lymphocyte assay, and 1 utilized a muscle biopsy for tion. Given the rarity of the two conditions, this sibling pair with dual diagnosis is analysis. Conclusions: Pompe disease is a heterogeneous disease with a broad range notable. However, development of sarcoidosis did not accelerate the Gaucher phe- of clinical symptoms as shown by the first 27 patients enrolled in the Pompe Regis- notype, presumably because both patients were adequately treated with ERT. try. The Pompe Registry is a voluntary, international program that attempts to in- crease the understanding of this rare disease, its natural history, and, therefore, to potentially improve patient management. BIOCHEMICAL GENETICS POSTER PRESENTATIONS 53 54 Respiratory failure and severe rhabdomyolysis in an adolescent with CPT2 de- Peptiduria in autism and related disorders: An exploratory study. S.G. ficiency precipitated by influenza A infection. M.J Dasouki1, M.A Jackson2, L. Kahler1,2, E. Cooper1. 1Genetic Health Services Victoria, Murdoch Childrens Re- Sweetman3, D.S Roe3, C.R Roe3. 1ST.Luke’s Medical Genetics Clinic; 2Children’s search Institute, Royal Children’s Hospital, Melbourne VIC Australia; 2Dept of Mercy Hospital. School of Medicine. University of Missouri-Kansas City. Kansas Pediatrics, Johns Hopkins Hosp, Baltimore, MD. City, MO; 3Institue of Metabolic Disease. Baylor University School of Medicine. The autism spectrum disorders are defined by behavioral phenotypes, often ac- Dallas, TX. companied by developmental delay. Biological aspects of autism include alterations Carnitine Palmitoyl Transferase 2 (CPT2) is an inner mitochondrial membrane of serotonin chemistry, subtle but consistent abnormalities of immune function, and beta-oxidation enzyme involved in long chain fatty acid metabolism. Exercise, in- excessive amounts of small peptides in the urine. Many of these peptides have been fection, drugs(statins and valproic acd) are known to induce rhabdomyolysis in identified as being fragments of gluten and casein. Some have opioid activity and CPT2 deficient patients. Influenza-associated myositis (IAM) is thought to be an in- may contribute to the behavioral features of autism. Intestinal symptoms are com- frequent and poorly known complication of influenza virus infection. A recent liter- mon and a new form of enterocolitis has been described in autistic children. Avoid- ature review showed that 10/316 patients (3%) developed rhabdomyolysis which led ance of gluten and casein has been reported to be beneficial in diminishing autistic to renal failure in 8 patients. Influenza A virus was identified more frequently. Here, behavior, and ameliorating the intestinal symptoms. Identification of the peptide we describe a 14-year old white male who was admitted to the pediatric intensive fragments by others has been done by chromatography with synthetic standards and care unit (PICU) following respiratory failure and severe rhabdomyolysis which by using specific antibodies. The identification of these peptides by mass spectrom- were associated with influenza A infection. He recovered fully with supportive care etry has not been published. We therefore undertook to replicate work published by without impairement of renal function. Due to history of muscle weakness, metabol- others (especially KL Reichelt and R Cade), with the eventual goal of confirming the ic studies (plasma acylcarnitines, urine organic acids) were performed. The diagno- identity of the various putative peptides, and quantifying them. Urine samples (first sis of CPT2 deficiency was made based on abnormal plasma acylcarnitines, morning when possible) were obtained from children ages 0-12 years old diagnosed abnormal skin fibroblast fatty acid oxidation profile and low (17%) skin fibroblast with autism(N=120), developmental delay (59),global developmental delay (18), CPT2 activity. We therefore suggest that such patients with severe and complex "in- speech delay (30), intellectual delay (12), and healty children ages 3-12 (39). Diag- fluenza" presentation may be gentically predisposed. A detailed metabolic evalua- nostic category was determined by requesting physician. Samples standardized for tion for a possible defect in fatty acid "mitochondrial" beta-oxidation is therefore creatinine content were analyzed by HPLC C-18 reverse-phase column with UV de- recommended. tectors at 215 and 280 nM, using 0.1% TFA/ 0.1% TFA-95% acetonitrile. Peptiduria was quantitated as area under the curve (AUC) after hippurate (30 minutes) till the end of the peptide region (68 minutes). We also quantitated the AUC of each peak. However it is not certain that similar peaks from different samples represent the same substance. Retention times were standardized as multiples of the hippurate re- tention time. Up to 35 peaks could be seen in a sample. Putative peaks include cis- indolylacryloylglycine (cis-IAG), casomorphin (CM) A5, beta (b) CM 1-4 amide, trans-IAG, gliadinomorphin (alpha-gliadin) , bCM 1-7, bCM 1-8. The identification of bCM 1-4 was confirmed by mass spectrometry. Replicate analyses gave consist- ent results in retention time and AUC for each peak. The mean values (AUC) for most peaks and total AUC were similar between controls and patients, but the high values and outliers almost invariably were associated with abnormality, leading to significant skewing of the data from the patient groups. The finding of increased amounts of putative peptides in the urine of some children with autism or other de- velopmental problems may reflect altered intestinal function, or shared pathogene- sis. Further characterization of the peaks is now needed to understand their significance. A16
    • POSTER PRESENTATIONS BIOCHEMICAL GENETICS 55 56 Safety and Efficacy of CHO-cell derived Recombinant Human Acid Alpha Glu- Pediatric Screening for Wilson Disease: A Pilot Study at Mayo Clinic. K.A. cosidase (rhGAA) in Patients with Infantile-onset Pompe Disease (IOPD) treat- Mensink1,2, C. Kroll1, S.J. Hartman1, M.J. Magera1, K.A. Hibbs1,2, D. Matern1,2,3, ed after 6 Months of Age. P. Kishnani1, C. Spencer2, M. Nicolino3, N. Leslie4, E. P. Rinaldo1,2,3, M. Ferber1, D.B. Dawson1, R.D. Hurt4, R.M. Jacobson3, S. Wraith5. 1Department of Pediatrics, Duke University Medical Center, Durham, NC; Hahn1,2,3. 1Department of Laboratory Medicine and Pathology, Mayo Clinic Col- 2Shands Hospital at the University of Florida, Gainesville, FL; 3Pediatrique Hopital lege of Medicine, Rochester, MN; 2Department of Medical Genetics, Mayo Clinic Debrousse, Lyon, France; 4Cincinnati Children’s Hospital Medical Center, Cincin- College of Medicine, Rochester, MN; 3Pediatric and Adolescent Medicine, Mayo nati, OH; 5Royal Manchester Hosptial, Manchester, UK. Clinic College of Medicine, Rochester, MN; 4Center for Patient Oriented Research, Background: Pompe disease is a rare autosomal recessive metabolic muscle dis- Mayo Clinic College of Medicine, Rochester, MN. ease caused by a deficiency of the lysosomal enzyme acid -glucosidase (GAA). Pa- Abstract: Population screening in the pediatric setting represents a new genre of tients with IOPD present before 1 year of life with cardiomyopathy, generalized preventive medicine. Wilson disease provides an excellent opportunity to pioneer muscle weakness, hypotonia, and severe motor delay. Death from cardio-respiratory this concept, as it meets the universal criteria for mass screening. Wilson disease is failure generally occurs before the first year. A subset of patients with IOPD has a an autosomal recessive disorder of copper metabolism. Diagnosis is typically de- slower progression of cardiomyopathy and longer survival. Twenty-one patients > 6 pendent upon the onset of severe hepatic and/or neurologic symptoms. This is regret- months of age were enrolled in a clinical trial to receive enzyme replacement therapy table because treatment is effective if diagnosis occurs prior to the onset of these life- (ERT) with rhGAA. An interim analysis of the first 15 patients treated for 6 months threatening symptoms. A sandwich ELISA assay was developed using anti-cerulo- is presented. Methods: This is an open-label, multinational, multicenter study. On- plasmin antibodies to measure the concentration of ceruloplasmin (CP) in dried set of symptoms <12 months of age and evidence of cardiomyopathy by echocardi- bloodspots. The simplicity of this assay provides a good way to investigate the fea- ogram (abnormal left ventricular mass index, LVMI) were criteria for inclusion. sibility of pediatric screening using Wilson disease as a first model. Patients received rhGAA at 20 mg/kg/qow IV. Results: The mean age at first symp- Method: Once informed consent is obtained, blood is collected on filter paper by toms was 3.7 months (range: 0-7.1 months), mean age of diagnosis was 9.0 months finger stick. Individuals who are acutely ill, pregnant or taking oral contraceptives (range: 1.9-22.6 months) and mean age at first infusion was 17.86 months (range: are excluded. The concentration of ceruloplasmin (CP) is measured by the ELISA 6.3-43.1 months). After 26 weeks of therapy, 12/15 patients (80%) were alive and 8/ assay, and abnormal results (CP <15mg/dl) are followed up by molecular genetic 10 patients (80%) who were free of invasive ventilation at baseline, remained so. All analysis of the ATP7B gene. This analysis includes direct sequencing of 21 exons patients treated for >3 months showed a reduction in LVMI (mean decrease of 34%). and the 5’ UTR region. 14/15 patients (93%) showed maintenance or improvement in growth parameters. 6/ Result: Intra-assay precision demonstrates acceptable coefficient of variation 15 patients (40%) demonstrated consistent gains in motor function. 4/15 patients within 20% of the expected values. The recovery for various concentrations aver- (27%) experienced infusion associated reactions (IARs), mild to moderate in sever- aged 90% of the expected values. As of December 9, 2004, the mean CP value was ity and treated symptomatically. No discontinuations due to IARs occurred. 3 pa- 44.1± 14.0 mg/dL (N=185). The mean CP in children less than 1 year of age (N=40) tients died in the first 3 months of ERT, all unrelated to rhGAA. 13/15 patients was 39.6 ± 14.4 mg/dL. Five participants (ages 8 months to 11 years) exhibited rel- (87%) developed IgG antibodies against rhGAA. Antibodies did not demonstrate an atively low CP levels that ranged from 15.1 to 18.5 mg/dL. However, no mutations inhibitory activity, as tested by an in vitro assay. Conclusions: IOPD presents within in the ATP7B gene were identified. the first 1 year of life with progression to death occurring rapidly thereafter. Admin- Conclusion: The sandwich ELISA assay demonstrates precision and accuracy. istration of rhGAA to this group of patients with IOPD was generally well tolerated. Thus, it appears to be a reliable method for population screening of Wilson disease LVMI improved while ventilator use status was maintained in most patients. Gains in the pediatric setting. The current cut-off for abnormal result (<15mg/dl) appears in motor function were observed in a subgroup of patients. In spite of the advanced appropriate. A pilot study is in progress to determine the effectiveness and efficiency stage of the disease at onset of ERT in most patients treated in this trial, administra- of this test on a larger scale. tion of rhGAA after 6 months of age resulted in measurable clinical benefit. Addi- tional trials in patients with IOPD treated before 6 months of age are underway. 57 58 In Vivo Expression of Human VLCAD in Mice. J.L. Merritt1, J. Vockley2, D. Maternal serum invasive trophoblast antigen (ITA) and first trimester Down Matern1,3, M. He2, J. Daniels1, D.B. Schowalter1. 1Department of Medical Genetics, syndrome screening. C.M. Strom1, G.E. Palomaki2, G.J. Knight2, L.M. Neveux2, Mayo Clinic, Rochester, MN; 2University of Pittsburgh School of Medicine and R. Pandian1, J.E. Haddow2. 1Quest Diagnostics Nichols Institute, San Juan Capist- Children's Hospital of Pittsburgh, Department of Pediatrics, Pittsburgh, PA; rano, CA; 2Foundation for Blood Research, Scarborough, Maine. 3Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN. Background: In the United States, Down syndrome screening is still performed Very long-chain acyl-CoA deyhydrogenase (VLCAD) deficiency is a disorder of mainly in the second trimester using three or four biochemical markers. Prenatal fatty acid β-oxidation that may present at any age with cardiomyopathy, skeletal screening in the first trimester, however, enables earlier diagnosis and usually in- muscle myopathy, and/or nonketotic hypoglycemia. The expansion of newborn cludes maternal serum pregnancy associated plasma protein-A (PAPP-A), the free screening programs allows us to identify patients with VLCAD deficiency at a point β-subunit of human chorionic gonadotropin (free β), and ultrasound measurement of in which effective therapeutic intervention can be initiated prior to the onset of nuchal translucency thickness (NT). We report herein a case / control study investi- symptoms. Current therapy for VLCAD deficiency consists primarily in the avoid- gating the possible inclusion of serum invasive trophoblast antigen (ITA) in first tri- ance of fasting, a diet low in long-chain fatty acids, and vitamin supplementation. mester screening. Nevertheless, the risk of severe metabolic decompensations in particular during Methods: As part of an earlier observational study, serum samples from 54 Down acute illness remains. The development of a safe, durable, and effective VLCAD syndrome and 276 unaffected pregnancies were collected between 9 and 15 weeks gene delivery system for use at the time of diagnosis could result in a significant im- gestation. Samples had been aliquotted and stored at -20°C for eight years. ITA was provement in the quality of life for patients with VLCAD deficiency. To this end, we measured and converted to weight-adjusted multiples of the median (MoM). These have developed a plasmid containing the human VLCAD cDNA under the control results were then combined with those of the other first trimester markers published of the strong CMV promoter and followed by the bovine poly-adenlyation signal in the earlier observational study. (pCMV-hVLCAD). A novel rabbit polyclonal anti-VLCAD antibody was prepared Results: Median ITA MoM levels in Down syndrome pregnancies increase as ges- using a 20 amino-acid peptide unique to the human VLCAD protein to study human tational age increases (2.37 MoM at 11, and 2.96 MoM at 13 completed weeks). At VLCAD expression in immune competent mice. VLCAD specificity was demon- 75% detection, maternal age in combination with ITA and PAPP-A measurements strated by Western analysis of human wild- type, VLCAD deficient, and transiently have a 7.7% false-positive rate, slightly lower that the 8.2% found for the maternal transfected VLCAD deficient fibroblasts with pCMV-hVLCAD. VLCAD deficient age, free β, and PAPP-A combination. Adding NT measurements reduces false-pos- fibroblasts transfected with pCMV-hVLCAD also showed partial correction of the itives for the two combinations to 2.0% and 1.8%, respectively. C14 and C16 metabolic block, and detectable activity by ETF reduction assay. Hy- Discussion: Serum ITA appears to be a useful first trimester Down syndrome drodynamic administration of this plasmid into immune competent Balb/c mice re- marker that could replace free β measurements while maintaining performance. sulted in hepatic expression of human VLCAD, which is not evident in untreated mice. In conclusion, we have developed a novel anti- human VLCAD antibody and a functional human VLCAD expression cassette, which can be used to test other vec- tor systems and in vivo correction of VLCAD deficiency in VLCAD deficient mice. A17