遗传学精品教学（南京大学）chapter 6 Single gene disorder.pptxVIP

Chapter 6 Single-gene Disorder;Basic Conception;What’s Monogenic Disorders?;The Basic Patterns of Single Gene Inheritance;5;OMIM Statistics for Oct. 05, 2015;7;8;Symbols are used to illustrate the various states and relationships of the family tree ;Pedigrees : They are graphic representations of a family tree which show the biological relationship of the proband (先证者) to the rest of the individuals. ;11;12;常染色体显性遗传Part 1 Autosomal Dominant Inheritance ;AD diseases are those in which a single copy of a mutant gene on autosome is enough for the trait to be expressed or shown. ;15;Example;Each affected individual has at least one affected parent, mostly hybrid;◆ 30～40岁发病，也有10多岁或60 岁以后发病 ◆ 有进行性不自主的舞蹈样动作，可合并肌强直 ◆ 可出现神经症状，如抑郁，智能衰退，最终成为痴呆;Huntingtin gene (HTT), also called HD and IT15, 4p16.3, CAG (codes for aa Q) repeats in the exon 1 form polyglutamine tract (or polyQ tract) Normal case 9-34 repeats, patients 37-100 repeats # of the repeats correlates the age of onset and severity Genetic imprinting or anticipation (遗传印记或早现) ;Trinucleotide (CAG)n ? polyQ;21;Pathobiological Change;23;24;More CLINICAL EXAMPLES;Brachydactyly, type A1 [短指(趾)症A1型];The phenotype of the heterozygote (Aa) will be intermediate between the phenotypes of the two homozygotes (AA or aa).;婚配类型和子代发病风险;常染色体隐性遗传 Part 2 Autosomal Recessive Inheritance;Pedigree Characteristics;Both parents are carriers, mostly;CLINICAL EXAMPLES;33;OCA: due to absence or defect of tyrosinase, a copper-containing enzyme involved in the production of melanin. It is the opposite of melanism, different from melanoma. Tyrosinase activity is very important to be balanced. Several polyphenols, including flavonoids or stilbenoid, substrate analogues, free radical scavengers, and copper chelators, have been known to inhibit tyrosinase. Henceforth, the medical and cosmetic industries are focusing research on tyrosinase inhibitors to treat skin disorders. ;婚配类型和子代发病风险;X 连锁的显性遗传part 3 X-linked Dominant Inheritance;1.致病基因在X染色