Type of inheritance umi
- 1. Type of Inheritance Autosomal Dominant Autosomal Recessive X-linked Sporadic Mitochondrial inheritance Budu, M.D, Ph.D Combined-Degree Lecture V-1 Wed. May 18, 2005
- 3. Autosomal Dominant Dominant conditions are expressed in individuals who have just one copy of the mutant allele. The pedigree on the right illustrates the transmission of an autosomal dominant trait. Affected males and females have an equal probability of passing on the trait to offspring. Affected individual's have one normal copy of the gene and one mutant copy of the gene, thus each offspring has a 50% chance on inheriting the mutant allele. As shown in this pedigree, approximately half of the children of affected parents inherit the condition and half do not. Autosomal Dominant
- 4. Autosomal Recessive Recessive conditions are clinically manifest only when an individual has two copies of the mutant allele. When just one copy of the mutant allele is present, an individual is a carrier of the mutation, but does not develop the condition. Females and males are affected equally by traits transmitted by autosomal recessive inheritance. When two carriers mate, each child has a 25% chance of being homozygous wild-type (unaffected); a 25% chance of being homozygous mutant (affected); or a 50% chance of being heterozygous (unaffected carrier). Affected individuals are indicated by solid black symbols and unaffected carriers are indicated by the half black symbols.
- 5. X-linked Recessive X-linked recessive traits are not clinically manifest when there is a normal copy of the gene. All X-linked recessive traits are fully evident in males because they only have one copy of the X chromosome, thus do not have a normal copy of the gene to compensate for the mutant copy. For that same reason, women are rarely affected by X-linked recessive diseases, however they are affected when they have two copies of the mutant allele. Because the gene is on the X chromosome there is no father to son transmission, but there is father to daughter and mother to daughter and son transmission. If a man is affected with an X- linked recessive condition, all his daughter will inherit one copy of the mutant allele from him.
- 6. X-linked Dominant Because the gene is located on the X chromosome, there is no transmission from father to son, but there can be transmission from father to daughter (all daughters of an affected male will be affected since the father has only one X chromosome to transmit). Children of an affected woman have a 50% chance of inheriting the X chromosome with the mutant allele. X-linked dominant disorders are clinically manifest when only one copy of the mutant allele is present.
- 7. Sporadic Inheritance I II III 1 2 2 3 4 5 61 1 2 Female with normal fundi Male with normal fundi Affected Female Proband Deceased Examined in this study The only one of the family members share the mutation and the phenotype
- 8. Children inherit their mitochondrial DNA only from their mother, unlike nuclear DNA which comes from the mother and father. Girls will always pass on a mtDNA mutation (genetic error or defect) and boys will never pass on a mtDNA mutation. Thus, a child shares the same mtDNA sequence as does his/her siblings and mother, but not his/her father. In addition, the mother's siblings and her mother (the child's maternal aunts, uncles and grandmother) and more distant maternal relatives also share this same mtDNA. In practice, siblings and the mother often are affected with variable manifestations of energy deficiency, while the maternal aunts, uncles and/or grandmother are sometimes affected. Mitchondrial/maternal inheritance
- 9. Thank you