The Patterns of Genetic Inheritance-2 PDF

The Patterns of Genetic Il Inheritance-2 by Dr.Ezat Mersal  The Patterns of Genetic Inheritance  I. What is a pedigree?  A. Definition  B. Uses  II. Constructing a pedigree  A. Symbols  B. Connecting the symbols  III...

The Patterns of Genetic Il Inheritance-2 by Dr.Ezat Mersal  The Patterns of Genetic Inheritance  I. What is a pedigree?  A. Definition  B. Uses  II. Constructing a pedigree  A. Symbols  B. Connecting the symbols  III. Interpreting a pedigree  Autosomal dominant Inheritance Autosomal Dominant & complicating factors Autosomal complicating Non-penetrance Sex-limited/sex influenced New mutation Germline mosaicism Adult-onset conditions Anticipation Consanguinity Heterogeniety Interaction Pleiotropy  15129410475 - 005- See gy skip !  An instance in which an individual has a trait-associated or disease-causing genetic variant, but the individual does not have the phenotype or condition. An individual who inherits the disease gene does not develop the disorder (heterozygote 89pys > - & having no clinical features) 91g The disorder appears to “skip” generations Eg: Retinoblastoma ( malignant eye tumor) © 2015 John Wiley & Sons, Inc. All rights reserved.  · ins  Sex-influenced traits are · autosomal traits that are - give influenced by sex. > - · min Sis  If a male has one recessive allele, he will show that trait, but it will take two recessive % for the female to show that ma same trait. Gene expression limited to specific sex Disorder/trait may appear to “skip” generations © 2015 John Wiley & Sons, Inc. All rights reserved.  An alteration occurs in the egg or sperm that made the affected individual (may be first family member to be affected) Recurrence risk for unaffected parents is considered to be low Risk of new mutation is associated with advanced paternal age in some disorders - Se m ; 20 9 95 exten usas. - · a Eg: 7/8 of cases of achondroplasia are caused by new mutation , only 1/8 are transmitted by achondroplastic parents © 2015 John Wiley & Sons, Inc. All rights reserved.  852 Do ag'dis 1 ·. , 18 % s diojgg) da single oj An individual who inherits the disease gene but does not develop the condition until adulthood Examples: Huntington disease (death of brain cells) most hereditary cancer syndromes © 2015 John Wiley & Sons, Inc. All rights reserved.  21s 21s strong week gvel's S i ↑ A -51 5 Variability of severity of  disorder among individuals  with same genotype Examples: Neurofibromatosis (NF1,2,3,) : tumor in the NS Treacher-Collins syndrome (craniofacial deformities) © 2015 John Wiley & Sons, Inc. All rights reserved. &1v/g 51 ve jenis to  The presence of variants at different gene loci that cause the same or similar phenotypic expressions of a disease or condition. Examples: -0005 8. Ehler – Danlos > -9 - psg Syndromes. Hereditary Deafness. Retinitis Pigmentosa Tuberous Sclerosis © 2015 John Wiley & Sons, Inc. All rights reserved. giyis Niesss · - We wes Se%. "Wit ass A single locus is responsible for a number of distinct and seemingly unrelated phenotypic effect. Examples:  Marfan syndrome © 2015 John Wiley & Sons, Inc. All rights reserved.  Basic genetics : a human approach / BSCS. Dubuque, IA, Kendall/Hunt Pub. Co., c1999. 147 p. QH431.B305 1999  Genes, ethnicity, and ageing. Edited by Lincoln H. Schmitt, Leonard Freedman, Rayma Pervan. Nedlands, Australia, Centre for Human Biology, University of Western Australia ; Singapore, River Edge, NJ, World Scientific, c1995. 100 p.QH455.G45 1995  Genetic polymorphisms and susceptibility to disease. Edited by M. S. Miller and M. T. Cronin. New York, Taylor & Francis, 2000. 266 p.