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Contact detailsContact details
Medical Technology DepartmentMedical Technology Department
Genetics labGenetics lab
fsharif@iugaza.edufsharif@iugaza.edu
Textbook:Textbook: Genetics in Medicine, 7Genetics in Medicine, 7thth edition. Nussbaum, McInnes edition. Nussbaum, McInnes
& Willard. W.B. Saunders Co. (2007).& Willard. W.B. Saunders Co. (2007).
ReferenceReference Emery’s Elements of Medical Genetics, 13Emery’s Elements of Medical Genetics, 13thth edition, edition,
Turnpenny & Ellard. Churchill Livingstone. (2007). Turnpenny & Ellard. Churchill Livingstone. (2007).
GradesGrades
Midterm examMidterm exam 30%30% Assignments, participation & quizzesAssignments, participation & quizzes 10%10% Final examFinal exam 60%60%
TopicsTopics
1: Introduction 2: Patterns of Single-Gene Inheritance 3: Genetic Variation in Individuals 4: Genetic Variation in Populations 5: Gene Mapping 6: Principles of Clinical Cytogenetics 7: Clinical Cytogenetics: Disorders of the Autosomes and
the Sex Chromosomes 8: Treatment of Genetic Diseases 9: Genetics and Cancer 10: Prenatal Diagnosis
Glossary & Definitions
Genetics is concerned with variation and heredity in all living organisms
Human genetics is the science of variation and heredity in humans
Medical genetics deals with human genetic variation of significance in medical practice and research
Cytogenetics: the study of chromosomes
Glossary & DefinitionsGlossary & Definitions
Genomics: the study of genome, its organization and functions
Population genetics: genetic variation in human populations and factors that affect allele frequencies
Clinical genetics: application of genetics to diagnosis and patient care
Genetic counseling: risk information, psychological and educational support to patients and/or their families
Glossary & DefinitionsGlossary & Definitions
Genotype - the genetic constitution of Genotype - the genetic constitution of the organismthe organism
Phenotype - the observable expression Phenotype - the observable expression of genotypeof genotype
Glossary & DefinitionsGlossary & Definitions
LocusLocus - a chromosomal location - a chromosomal location
AllelesAlleles - alternative forms of the same locus - alternative forms of the same locus
MutationMutation - a change in the genetic material, - a change in the genetic material, usually rare and pathologicalusually rare and pathological
PolymorphismPolymorphism - a change in the genetic - a change in the genetic material, usually common and not necessarily material, usually common and not necessarily pathologicalpathological
Glossary and DefinitionsGlossary and Definitions
HomozygoteHomozygote - - an organism with two identical an organism with two identical allelesalleles
HeterozygoteHeterozygote - an organism with two different - an organism with two different allelesalleles
HemizygoteHemizygote -- having only one copy of a genehaving only one copy of a gene Males are hemizygous for most genes on the sex Males are hemizygous for most genes on the sex
chromosomeschromosomes
Dominant traitDominant trait -- a trait that shows in a a trait that shows in a heterozygoteheterozygote
Recessive traitRecessive trait - a trait that is hidden in a - a trait that is hidden in a heterozygoteheterozygote
Glossary and DefinitionsGlossary and Definitions
Family history is importantFamily history is important
It can be critical in diagnosisIt can be critical in diagnosis Can provide info about natural history of Can provide info about natural history of
the disease & variation in its expressionthe disease & variation in its expression Can clarify pattern of inheritanceCan clarify pattern of inheritance
Note:Note:
Diagnosis of a hereditary condition allows risk Diagnosis of a hereditary condition allows risk estimation in other family members so that estimation in other family members so that proper management, prevention, & counseling proper management, prevention, & counseling can be offered to patient & familycan be offered to patient & family
Role of Genes in Human DiseaseRole of Genes in Human Disease Most diseases / phenotypes result from the interaction
between genes and the environment
Some phenotypes are primarily genetically determined Achondroplasia
Other phenotypes require genetic and environmental factors Mental retardation in persons with PKU
Some phenotypes result primarily from the environment or chance
Lead poisoning
Major types of genetic Major types of genetic diseasedisease
Chromosomal disordersChromosomal disorders
Single gene disordersSingle gene disorders
Polygenic diseasesPolygenic diseases
Chromosomal disordersChromosomal disorders
Addition or deletion of entire chromosomes Addition or deletion of entire chromosomes or parts of chromosomes. Rearrangement or parts of chromosomes. Rearrangement of chromosomal segments of chromosomal segments
Typically more than 1 gene involvedTypically more than 1 gene involved
Classic example is trisomy 21 - Down Classic example is trisomy 21 - Down syndromesyndrome
Single gene disorders Single gene disorders
Single mutant gene has a large effect on Single mutant gene has a large effect on the patientthe patient
Transmitted in a Mendelian fashionTransmitted in a Mendelian fashion Autosomal dominant, autosomal Autosomal dominant, autosomal
recessive, X-linked, Y-linkedrecessive, X-linked, Y-linked Osteogenesis imperfecta - Osteogenesis imperfecta - autosomal dominantautosomal dominant
Sickle cell anemia - Sickle cell anemia - autosomal recessiveautosomal recessive
Haemophilia - Haemophilia - X-linkedX-linked
Polygenic diseasesPolygenic diseases
The most common yet still the least understood The most common yet still the least understood of human genetic diseasesof human genetic diseases
Result from an interaction of multiple genes, Result from an interaction of multiple genes, each with a minor effecteach with a minor effect
The susceptibility alleles are commonThe susceptibility alleles are common
Type I and type II diabetes, autism, multiple Type I and type II diabetes, autism, multiple sclerosissclerosis
Identifying disease genes has Identifying disease genes has been revolutionized by the been revolutionized by the
sequencing of the sequencing of the Human Genome Human Genome
The sequenceThe sequence
3.3 billion base pairs3.3 billion base pairs
Gene prediction ~ 25,000Gene prediction ~ 25,000
This is likely to be an underestimation due This is likely to be an underestimation due to the occurrence of regulatory RNAsto the occurrence of regulatory RNAs
Accessing the sequenceAccessing the sequence
Public databasesPublic databases
Freely availableFreely available
Continuously modified and updatedContinuously modified and updated
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