* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Fumarase Deficiency
Survey
Document related concepts
Tay–Sachs disease wikipedia , lookup
Gene therapy wikipedia , lookup
Genome (book) wikipedia , lookup
Saethre–Chotzen syndrome wikipedia , lookup
Epigenetics of neurodegenerative diseases wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Neuronal ceroid lipofuscinosis wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Genome editing wikipedia , lookup
Designer baby wikipedia , lookup
Point mutation wikipedia , lookup
Transcript
PHM142 Fall 2016 Instructor: Dr. Jeffrey Henderson Fumarase Deficiency Dharen Ratnakumar, Arvind Grewal, Amir Khela, Rikesh Patel September 27, 2016 What is Fumarase Deficiency? • Autosomal recessive metabolic disorder • Extremely Rare Disorder • Approximately 100 cases reported https://en.wikipedia.org/wiki/Fumarase_deficiency#/media/File:Autorecessive.svg What is Fumarase Deficiency? Deficiency of the enzyme fumarate hydratase (fumarase) Found in Kreb cycle https://en.wikipedia.org/wiki/Fumarase#/media/File:Reaction1.png Fumarase Mechanism of Action (Hydration) https://en.wikipedia.org/wiki/Fumarase#/media/File:FumaraseMechanismE1CB.png Cellular Respiration http://florianbrnada.weebly.com/uploads/1/7/9/4/17946175/5696532.jpg?597 Kreb’s Cycle https://upload.wikimedia.org/wikipedia/en/4/45/Citric_acid_cycle_noi.JPG Fumarase - Two Isoforms - Cytosolic Form - Mitochondrial Form - Extended N-Terminus - Identical subunits - Tetrameric Enzyme (54kDa each) - Binding Site A (E315) - Affinity for Fumarate, D-malate, and Oxaloacetate - Competitive Inhibitors: Glycine - Binding Site B - Lower affinity for same substrates http://www.ncbi.nlm.nih.gov/Structure/icn3d/full.html?showseq=1&mmdbid=66080&buidx=0 Fumarase Inhibitors Competitive Inhibitors: - Maleic Acid: found in drugs like Carfenazine & Chlorpheniramine - Glutaric Acid: by-product of Tryptophan catabolism - D-Tartaric Acids: added to oral drugs to improve taste, such as cough syrups Molecular Genetics FH gene located on the long arm of chromosome 1 17 FH gene mutations known to cause fumarase deficiency ● Mainly missense mutations Parents of affected child are unaffected obligate heterozygotes Clinical Characteristics The clinical presentation of Fumarase Deficiency in a patient is characterized by: Encephalopathy Major cognitive deficiencies Epileptic seizures Irregular facial features and brain malformation Clinical Characteristics Brain Imaging ● Most common finding is a small brain ○ Cerebral atrophy ○ Ventriculomegaly Clinical Course ● Many individuals do not survive infancy ● Death due to secondary complications (eg. respiratory failure) ● Patients unable to feed ● A few cases have lived into early adulthood Clinical Diagnosis Increased concentration of Fumaric Acid in the urine. Confirmation of diagnosis through identification of deficient fumarate hydratase enzyme activity. Fibroblasts Lymphoblasts White Blood Cells Enzyme activity of affected individuals usually 10% of the control group. Genetic testing of FH gene Sequence analysis to determine mutant alleles. Most frequent mutant allele is c.1431_1433dupAAA Amplification of sequence through qPCR. Genetic Testing Sample of DNA taken. Denaturation of DNA followed by the primer annealing and extension. Sequence comparison to the normal allele. Sequence analysis of entire coding region Deletion/Duplication analysis Testing for Fumarase Deficiency often included in tests for other genetic disorders. E.g. Comprehensive Epilepsy NGS Panel, includes Fumarase Deficiency as well as 3052 other conditions. Treatment Extent of Deficiency MRI and evaluation by neurologist. Management of epileptic seizures Numerous medications but not the ketogenic diet. Nutritional treatment Management of lethargy and other symptoms associated with the encephalopathy. Physical therapy Management of the physical defects that can lead to such diseases as Scoliosis. Summary • A rare autosomal recessive metabolic disorder leading to the deficiency of the enzyme fumarase • Mitochondrial Fumarase converts Fumarate to Malate in Kreb’s cycle through hydration reaction • It is enzyme with four identical subunits (50kDa each, tetramer) • Binding site A with higher affinity than binding site B for Fumarate • 17 known mutations to FH gene on chromosome 1 cause fumarase deficiency • Diagnosis through Fumarate Hydratase and FH Gene testing • No direct treatment for Fumarase deficiency, rather addressing the many symptoms Summary cont. https://upload.wikimedia.org/wikipedia/en/4/45/Citric_acid_cycle_noi.JPG References Gellera, C.; Uziel, G.; Rimoldi, M.; Zeviani, M.; Laverda, A.; Carrara, F.; DiDonato, S. (March 1990). "Fumarase deficiency is an autosomal recessive encephalopathy affecting both the mitochondrial and the cytosolic enzymes". Neurology. 40 (3 Part 1): 495– 499. Coughlin, E. M., Christensen, E., Kunz, P. L., Krishnamoorthy, K. S., Walker, V., Dennis, N. R., ... & Ramesh, V. (1998). Molecular analysis and prenatal diagnosis of human fumarase deficiency. Molecular genetics and metabolism,63(4), 254-262. Pereira de Padua, R. A., & Nonato, M. C. (2014). Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of recombinant human fumarase. Acta Crystallographica Section F: Structural Biology Communications, 70(1), 120-122. Bulku, A., Aleksanyan, N., & Berkmen, M. (2016). Oligomerization of wild-type fumarase and a mutant associated with fumarate hydratase deficiency.The FASEB Journal, 30(1 Supplement), 665-6. Massey, V. (1953). Studies on fumarase. 4. The effects of inhibitors on fumarase activity. Biochemical Journal, 55(1), 172. Bartlett, J. M. S.; Stirling, D. (2003). "A Short History of the Polymerase Chain Reaction". PCR Protocols. Methods in Molecular Biology. 226 (2nd ed.). pp. 3–6.