Xlinked recessive inheritance where the father is affected

  • Slides: 20
Download presentation
X-linked recessive inheritance where the father is affected: the basics a tutorial to show

X-linked recessive inheritance where the father is affected: the basics a tutorial to show the genes segregate to give the typical pedigree pattern Professor P Farndon, Clinical Genetics Unit, Birmingham Women’s Hospital 13. 11. 06

Question: How can one understand the risks of an Xlinked recessive condition where a

Question: How can one understand the risks of an Xlinked recessive condition where a father is affected? I: 1 III: 1 IV: 1 III: 2 IV: 2 II: 2 III: 3 III: 4

Question: How can one understand the risks of an Xlinked recessive condition where a

Question: How can one understand the risks of an Xlinked recessive condition where a father is affected? Answer: By imagining which of the sex chromosomes of the parents have been passed on to children as shown on the next few screens Gene Reminder: Hemizygotes (males) with one copy of the altered gene are affected X-Chromosome

Male karyotype Female karyotype Humans have 23 pairs of chromosomes: 22 pairs of autosomes

Male karyotype Female karyotype Humans have 23 pairs of chromosomes: 22 pairs of autosomes and 1 pair of sex chromosomes

The male sex chromosomes: an X and a Y The female sex chromosomes: two

The male sex chromosomes: an X and a Y The female sex chromosomes: two X chromosomes

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father An affected male will have an

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father An affected male will have an X chromosome with a altered gene and a Y chromosome Mother A woman who is not a carrier of an Xlinked recessive disorder has two copies of the normal gene - one on each X chromosome

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X The father passes

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X The father passes on either his X chromosome containing the altered gene Y or his Y chromosome (and so determines the sex of the fetus) X The mother passes on one X or the other of her X chromosomes (both with normal genes)

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Y X There

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Y X There are four different combinations of the two chromosomes from each parent X

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Y X Offspring

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Y X Offspring This child has inherited the paternal X chromosome with the altered gene (and so is female) and the maternal X chromosome with the normal gene Daughter X

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Y X X

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Y X X Offspring Daughter This child has inherited the paternal X chromosome with the altered gene (and so is female) and the other maternal X chromosome with a normal gene

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Y X Offspring

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Y X Offspring Daughter Son X

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Y X Offspring

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Y X Offspring This child has inherited the paternal Y chromosome (and so is male) and a maternal X chromosome with a normal gene Son X

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Y X X

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Y X X Offspring Daughter Son

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Y X X

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Y X X Offspring This child has inherited the paternal Y chromosome (and so is male) and the other maternal X chromosome with a normal gene Son

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Offspring Daughter Y

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Offspring Daughter Y X X Which children are affected by the disease? Daughter Son

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Unaffected carrier Daughter

X-LINKED RECESSIVE INHERITANCE: father affected Parents Affected Father Mother Gametes X Unaffected carrier Daughter Y Unaffected carrier Daughter X X Unaffected male Son

X-LINKED RECESSIVE INHERITANCE: father affected All the children of a male with an X-linked

X-LINKED RECESSIVE INHERITANCE: father affected All the children of a male with an X-linked recessive disorder are therefore unaffected by his X-linked disease. All his daughters will be carriers. Their sons will inherit either the X-chromosome with the normal gene or the Xchromosome with the altered gene.

Examples of X-linked recessive diseases UK frequency / 10, 000 males Fragile X syndrome

Examples of X-linked recessive diseases UK frequency / 10, 000 males Fragile X syndrome 5 Non-specific X-linked mental retardation 5 Duchenne muscular dystrophy 3 Becker muscular dystrophy 0. 5 Haemophilia A (factor VIII) 2 Haemophilia B (factor IX) 0. 3

X-linked recessive conditions are part of the group of single gene disorders, which also

X-linked recessive conditions are part of the group of single gene disorders, which also include autosomal dominant and recessive disorders. They are important clinically because of the high risks to other family members. Gene X-Chromosome

The end! • Thank you for completing this revision aid • We are interested

The end! • Thank you for completing this revision aid • We are interested in your comments about this aid. Please email Professor Farndon. (p. a. farndon@bham. ac. uk) © P Farndon 2003

XLinked Inheritance Xlinked recessive disorders Responsible gene onXLinked Inheritance Xlinked recessive disorders Responsible gene on
Lecture 7 XLinked Inheritance Xlinked recessive disorders ResponsibleLecture 7 XLinked Inheritance Xlinked recessive disorders Responsible
Autosomal Recessive Inheritance Characteristics of autosomal recessive inheritanceAutosomal Recessive Inheritance Characteristics of autosomal recessive inheritance
XLinked ALD Nikhil Desen What is Xlinked ALDXLinked ALD Nikhil Desen What is Xlinked ALD
Mendelian Pedigree patterns Autosomal dominant Autosomal recessive XLinkedMendelian Pedigree patterns Autosomal dominant Autosomal recessive XLinked
Mendelian Pedigree patterns Autosomal dominant Autosomal recessive XLinkedMendelian Pedigree patterns Autosomal dominant Autosomal recessive XLinked
Mendelian Pedigree patterns Autosomal dominant Autosomal recessive XLinkedMendelian Pedigree patterns Autosomal dominant Autosomal recessive XLinked
Mendelian Pedigree patterns Autosomal dominant Autosomal recessive XLinkedMendelian Pedigree patterns Autosomal dominant Autosomal recessive XLinked
Recessive spastic paraplegias Paula Coutinho Porto Portugal RecessiveRecessive spastic paraplegias Paula Coutinho Porto Portugal Recessive
Dominant Recessive Traits Hidden Genes Dominant Recessive TraitsDominant Recessive Traits Hidden Genes Dominant Recessive Traits
1 father dias aris father dias dionysus father1 father dias aris father dias dionysus father
Xlinked and mitochondrial inheritance pattern Dr Eva MasieroXlinked and mitochondrial inheritance pattern Dr Eva Masiero
Xlinked dominant inheritance the basics a tutorial toXlinked dominant inheritance the basics a tutorial to
Xlinked inheritance of Fanconi anemia complementation group BXlinked inheritance of Fanconi anemia complementation group B
XLinked Inheritance Sex Linked Humans have 23 pairsXLinked Inheritance Sex Linked Humans have 23 pairs
Chapter 12 Chromosomal Inheritance Outline XLinked Alleles HumanChapter 12 Chromosomal Inheritance Outline XLinked Alleles Human
Xlinked inheritance Oliver Quarrell Lecture Plan Lyon hypothesisXlinked inheritance Oliver Quarrell Lecture Plan Lyon hypothesis
Gregor Mendel and Inheritance The Father of InheritanceGregor Mendel and Inheritance The Father of Inheritance
Multifactorial inheritance complex inheritance the inheritance determined byMultifactorial inheritance complex inheritance the inheritance determined by