Changes

•In females, a mutation would have to occur in both copies of the gene to cause the disorder.

•In females, a mutation would have to occur in both copies of the gene to cause the disorder.

•In males, one altered copy of the gene in each cell is sufficient to cause the condition.

•In males, one altered copy of the gene in each cell is sufficient to cause the condition.

•males are affected by X-linked recessive disorders much more frequently than females.

•males are affected by X-linked recessive disorders much more frequently than females.

||hemophilia, Fabry disease

||hemophilia, Fabry disease

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|Y-linked || •Caused by mutations in genes on the Y chromosome.

|Y-linked || •Caused by mutations in genes on the Y chromosome.

•So, the mutation can only be passed from father to son.

•So, the mutation can only be passed from father to son.

||Y chromosome infertility, some cases of Swyer syndrome

||Y chromosome infertility, some cases of Swyer syndrome

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||Autosomal dominant || •One mutated copy of the gene in each cell is sufficient for a person to be affected.

||Autosomal dominant || •One mutated copy of the gene in each cell is sufficient for a person to be affected.

•An affected person can inherit the condition from an affected parent.  

•An affected person can inherit the condition from an affected parent.  

•the condition may result from a new mutation in the gene (e, without any family history)

•the condition may result from a new mutation in the gene (e, without any family history)

||Huntington disease, Marfan syndrome

||Huntington disease, Marfan syndrome

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||Autosomal recessive ||Both copies of the gene in each cell should have mutations.

||Autosomal recessive ||Both copies of the gene in each cell should have mutations.

•Typically not seen in every generation of an affected family.

•Typically not seen in every generation of an affected family.

||cystic fibrosis, sickle cell disease

||cystic fibrosis, sickle cell disease

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||Codominant || •Two different versions (alleles) of a gene are expressed.

||Codominant || •Two different versions (alleles) of a gene are expressed.

•Both alleles influence the genetic trait or determine the characteristics of the genetic condition.

•Both alleles influence the genetic trait or determine the characteristics of the genetic condition.

|| ABO blood group, alpha-1 antitrypsin deficiency

|| ABO blood group, alpha-1 antitrypsin deficiency

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|Mitochondrial ||•Also known as maternal inheritance,  

|Mitochondrial ||•Also known as maternal inheritance,  

•Applies to the genes in mitochondrial DNA

•Applies to the genes in mitochondrial DNA

•As only egg cells contribute mitochondria to the developing embryo, only females can pass on mitochondrial mutations to their children.

•As only egg cells contribute mitochondria to the developing embryo, only females can pass on mitochondrial mutations to their children.

||Leber hereditary optic neuropathy (LHON)

||Leber hereditary optic neuropathy (LHON)