Genetics and Pathology

Am I not destroying my enemies when I make friends of them..? - Abraham Lincoln Genetic Disorders Dr.Venkatesh M. Shashidhar Senior Lecturer in Pathology Fiji School of Medicine Congenital Disorders  Non Genetic:  Developmental defects – Malformations  Genetic Disorders  Chromosomal  Gene - Mendelian  Multifactorial Mutations:  Genome: whole set – Polyploidy 4n, 8n etc.  Chromosomal: change in chromosome.  Number: Trisomy, monosomy  Structure: Deletion, Translocation etc.  Gene: Submicroscopic.  Point mutation – single base sequence  Deletions  Insertions Cell Cycle Mitosis Meiosis  Reduction Division (4n-2n)  Prophase-1(Synapsis, g.rec)  Metaphase-1  Anaphase-1  Telophase-1  Equatorial Division (2n-n)  Prophase-2  Metaphase-2  Anaphase-2  Telophase-2 Cytogenetic Abnormalities:  Abnormal number of chromosomes:  Non-disjunction - Down’s Syndrome  Anaphase lag - Turner’s xxx  Abnormal Structure: (normal no)  Deletion of short arm 5q- Cri-du-chat syndrome  Inversion  Translocation - Ph Chromosome - t(9:22) CML, Non-disjunction: Downs Karyotype: Trisomy-21 Downs Sy. Trisomy -21 Downs Syndrome - Trisomy-21 Downs Syndrome - Trisomy-21 Simian Crease Downs Syndrome:  Mental retardation  Neck folds  Epicanthic folds  Flat facial profile  Simian crease  Hypotonia  Umbilical hernia  Leukemia Cleft Lip - Trisomy 13: Syndactyly - Triploidy Polydactyly - Trisomy 13: Hydrops Fetalis – Monosomy X: Self Assessment Questions  Briefly describe congenital disorders?  What are mendelian disorders? Examples.  What is mutation? Classification?  Autosomal Dominant & Recessive disorders?  What is a karyotype? Uses  What is point mutation? Examples?  Polyploidy, aneuploidy, haploidy, diploid?