Human Genetic Disorders

1. Human GeneticDisorders Their symptoms…

2. Crouzon Syndromegenetic disorder, skull bones fuse, 1-25,000 are affected • *

3. Albinisminherit genes that do not make the proper amounts of pigment • !

4. Albinism • !

5. Cystic Fibrosis (CF)homozygous recessive trait on (autosomes) • *

6. Sickle Cell Anemia(substitution of adenine for thymine) homozygous recessive • *

7. Sickle Cell Anemia

8. Polydactyly(autosomal) homozygous recessive • *

9. Polydactyly

10. Webbing of Fingers(autosomal) • !

11. Webbing of Toes(autosomal) • *

12. Klinefelters Syndrome XXYNondisjunction • Tallness with extra long arms and legs • Abnormal body proportions (long legs, short trunk) • Enlarged breasts • Lack of facial and body hair • Small firm testes • Small penis • Lack of ability to produce sperm • Diminished sex drive • Sexual dysfunction • Learning disabilities • Personality impairment

13. Klinefelters syndrome presenting “leg ulcers” • 1/50 –1/1000 are born • With KS • Extra X chr. #47 • Due to anaphase lag • (fails to separate) • Chronic venus • Insufficiencies • Obesity • Reduced testosterone • Therapy (cause)

14. Turners syndrome XNondisjunction • Turner syndrome is a birth defect caused by the absence of an X chromosome in some or all cells of a female, which inhibits sexual development and usually causes infertility. • MONOSOMY – zygote with 45 chromosomes

15. Continue… • In Turner syndrome, an error occurring very early in development results in an abnormal number and arrangement of chromosomes. Most commonly, an individual with Turner syndrome will be born with 45 chromosomes in each cell rather than 46. The missing chromosome is an X chromosome. The affected person is always female

16. Mosaics… • More than half of all girls with Turner syndrome are mosaics, which means that the mutation occurs in some but not all cells of their body. Therefore, Turner syndrome can vary in severity. The fewer the affected cells, the milder the disease • 1 / 2,500 female births have turners syndrome

17. Symptoms of Turner Syndrome • short stature • webbed skin of the neck • abnormal eye features (drooping eyelids) • abnormal bone development, such as a "shield-shaped," broad flat chest • absent or retarded development of secondary sexual characteristics that normally appear at puberty, including sparse pubic hair and small breasts • coarctation (narrowing) of the aorta • bicuspid aortic valve • infertility • dry eyes • absence of menstruation

18. Webbed Neck

19. Webbed Neck

20. Turner’s syndrome

21. Mom and her daughter with Turner’s Syndrome • *

22. Down’s Syndromenondisjunction • *

23. Children with Down’s syndromeTrisomy 21 • *

24. Who gets dwarfism and bone dysplasias? • Bone dysplasias and dwarfism are rare. The most common type of dwarfism (achondroplasia) occurs in one in 15,000 children. • A defective gene that stops bone from growing in the usual way causes most bone dysplasias. Sometimes this gene is passed on from a parent to a child (genetic). • Much more often, though, the condition arises from a new change in the gene (spontaneous genetic mutation), and the baby is the first in her family to be affected.

25. Achondroplasia • !

26. *

27. Thumbelina has dwarfism • *

28. Huntington’s Disease (HD)(autosomal dominant allele) • *

29. Symptoms of HD • Mild forgetfulness and irritability • Appears between 30-40 yrs. Old • Loss of muscle control • Uncontrollable physical spasms • Severe mental illness • Eventually death