Genetic DisordersGenetic Disorders

A Collage of Multiple Syndromes

Syndromes Covered:Syndromes Covered:Chromosomal Disorders

• Down syndrome (Trisomy 21)

• Edward’s syndrome (Trisomy 18)

• Patau’s syndrome (Trisomy 13)

• Klinefelter’s syndrome (XXY)

• Turner syndrome (XO)

• Super female syndrome (XXX)

• Super male syndrome (XYY)

• Cri du Chat (deletion on #5)

• Fragile X (duplication on X)

Single Gene Disorders

• Sickle Cell Anemia

• Cystic Fibrosis

• Huntington’s Disease

• Autism (???)

…And, Sex Linked Traits

• Color Blindness

• Hemophilia

Chromosomal Disorders…are usually caused by an error in cell division

Karyotype!

Down Syndrome=Trisomy 21Down Syndrome=Trisomy 21

A young boy with Down syndrome

• members.aol.com/InitiativeDown/index.htm

This is what a karyotype of a girl with downs syndrome would look like

www.millerandlevine.com/genome/six.html

http://www.infobiogen.fr/services/chromcancer/IntroItems/PolyTri21Eng.html

Some physical characteristics of individuals with DS…Some physical characteristics of individuals with DS…

Edward’s Syndrome=Trisomy 18Edward’s Syndrome=Trisomy 18

Dakota, a young boy with Edward’s syndrome

www.childrenofpromise.net/dakotaphotos.html

• Mental retardation

• Undescended testicles in males

• Prominent back portion of the head

• Small head (microcephaly)

• Low-set, malformed ears

• Abnormally small jaw (micrognathia)

• Small mouth

• Cleft lip/Cleft palate

• Upturned nose

• Narrow eyelid folds (

palpebral fissures)

• Growth deficiency

• Feeding difficulties

• Breathing difficulties

• Developmental delays

Characteristics of Edward’s SyndromeCharacteristics of Edward’s Syndrome

A karyotype of a male with Edward’s syndrome

www.iupui.edu/~marrs/N100/ch10.html

Patau’s Syndrome=Trisomy 13Patau’s Syndrome=Trisomy 13

Meet Nicholas Wright the very proud son of Mark and Jayne Wright of Hudson,

Illinois USA

Nicholas was born with Trisomy 13.

www.trisomyonline.org/wright.htm

Characteristics of Patau’s SyndromeCharacteristics of Patau’s Syndrome

• Most embryos with trisomy 13 do not survive gestation and are spontaneously aborted.

• Of those surviving to term gestation, approximately 82-85% do not survive past 1 month of age, and 85-90% do not survive past 1 year of age.

• Central Nervous System malformations (no forebrain development)

• long term neurological disability, feeding difficulty, and frequent pneumonia and other respiratory infections.

• *There have been 5 cases reported in the medical history of patients living beyond 10 years of age

www.tokyo-med.ac.jp/genet/cki-e.htm

Klinefelter’s Syndrome (XXY)Klinefelter’s Syndrome (XXY)

William John Durfee, a patient with Klinefelter’s syndrome

tiger.towson.edu/~tmccor1/durf.htm

Male w/Klinefelter’s Female w/ Turner www.anselm.edu/homepage/jpitocch/genbio/geneticsnot.html

k-12.pisd.edu/currInst/science/Genetic/karyo-kline-xxy.htm

Turner Syndrome (XO)Turner Syndrome (XO)

Karen, a patient with Turner Syndrome

www.geocities.com/kare_50273/aboutturners.html

fig.cox.miami.edu/Faculty/Dana/25001_13.html

sp.uconn.edu/~bi107vc/sp03/terry/division.html

Super Female Syndrome Super Female Syndrome (Trisomy X)(Trisomy X)

Females with Trisomy X are healthy and cannot be distinguished from (XX) females excepts by karyotype (shown)

• http://www.biology.iupui.edu/biocourses/N100/images/XXXFemale.gif

Super Male Syndrome (XYY Super Male Syndrome (XYY Syndrome)Syndrome)

This syndrome is not well characterized although males that have XYY tend to be slightly taller than average

Studies have shown that a large number of men imprisoned are XYY

Other Genetic Disorders… Other Genetic Disorders… Cri du Chat Cri du Chat (Deletion on part (Deletion on part

of #5)of #5)• Characteristics:• “Cry of the cat," referring to the

distinctive cry of children with this disorder

• Abnormal larynx development, which becomes normal within a few weeks of birth

• Low birth weight • Respiratory problems

• Sometimes shortened lifespan…but usually normal life expectancy http://www.findhealer.com/glossary/images/

criduchat.gif

Fragile X Syndrome: Duplication of a Fragile X Syndrome: Duplication of a piece of the X Chromosomepiece of the X Chromosome

• Most common form of mental retardation

• Hyperactivity• Short attention span• Negative response to touch• Hand-flapping• Hand-biting• Poor eye contact• Repetition of words/phrases• Double jointed• Large or prominent ears• Large testicles

Single Gene Traits

Sickle Cell Anemia• Inherited blood disorder

(recessive)• Mostly affects people of

African ancestory• 1 in 12 African Americans have

it• Affects hemoglobin (which

carries oxygen in blood) and makes Red Blood Cells sticky

• Interesting correlation between sickle cell and increased resistance to malaria

Cystic Fibrosis

• Inherited chronic disease that affects lungs and digestive system

• Defective gene causes the body to produce unusually thick, sticky mucus

Huntington’s Disease

• Hereditary brain disorder that diminishes ability to walk, think, talk, and reason

• Onset usually between the ages of 30-45

Tay-Sachs Disease

• Lipid accumulation in brain cells; mental deficiency; blindness; death in early childhood

Autism

• 3 distinctive behaviors that characterize autism:    -difficulties with social interaction

-problems with verbal and nonverbal communication

-repetitive behaviors or narrow, obsessive interests. 

• These behaviors can range in impact from mild to disabling

Sex-Linked Traits…linked to the sex chromosomes

• Color Blindness

• Hemophilia

• Both are usually found in males only- why??

• Half shaded=carrier; If III-2 and III-3 have a child (I know...weird), what are the odds of it getting the “disease”?