Download MODE OF TRANSMISSION/ PATTERNS OF INHERITENCE

MODE OF TRANSMISSION/ PATTERNS OF INHERITENCE
Learning Objectives
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Enlist different mode of inheritance
Describe each type
Give examples of each type
Pattern of Inheritance
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Mendelian
Autosomal dominant
Autosomal recessive
X linked
Non Mendelian
Mitochondrial Inheritance
Monogenic
Inheritance
Autosoamal
Dominant
Sex Linked
Recessive
Dominant
X linked
Y linked
Recessive
Autosomal Dominant
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Males and females affected in equal proportions
Autosomal chromosomes
All generations are affected
Both parents transfer alleles to their offspring
Risk if both parents are affected?
Autosomal dominant
Autosomal Recessive
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Males and females affected in equal proportions
Skip Generation
Both parents can transmit alleles to the offspring
Consanguinity
Genetic risks
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Both parents affected
One parent affected
Both parents carriers
One diseased other is a carrier (pseudodominance)
Autosomal Recessive
X linked Recessive Diseases
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Affect males
Hemizygous for the allele
Mothers → affected sons
Father → carrier daughters → male grand children
No male – male transmission
Every generation is affected
Genetic Risks
Females can be affected
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Homozygosity for the allele
Skewed X inactivation
X linked Dominant Diseases
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Affected males→ all daughters
Affected female → 50% of her sons
Vitamin D resistant rickets
Males and females are affected but with an excess of
females
Females are less severely affected than males
X Linked Inheritance
X Linked dominant Inheritance
Y linked Inheritance
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Affected males only
Affected males transmit to their sons
Hairy ears
Spermatogenesis genes → azoospermia
Y linked Inheritance
Non Mendelian Inheritance
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Mitochondrial Inheritance
Phenotypic variability
Own DNA  16,569 bp, no intron
Cytoplasmic location it is exclusively inherited through maternal line
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No repair of DNA  10 time high mutation rate
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Reference
Kaplan Biochemistry & Medical Genetics