Chromosomal abnormalities

A presentation containing information about numerical and structural chromosomal abnormalities

1. CHROMOSOMAL ABNORMALITIES 4 ESO Biology and Geology IES Antonio Gala

2. What are chromosomal abnormalities ? These alterations can be detected by studying the affected person´s karyotype . There are many types of chromosomal abnormalities. However, they can be organized into two basic groups : Numerical abnormalities :  Structural abnormalities

3. Normal karyotype There are 46 chromosomes (23 homologous ones ) Homologous chromosomes are evenly banded )

4. Numerical abnormalities Changes in the number of chromosomes of a karyotype .

5. Numerical abnormalities Monosomy : an individual is missing one of the chromosomes from a pair. Trisomy : an individual has three chromosomes instead of a pair

6. Numerical abnormalities . MONOSOMY Turner´s syndrome (XO): Disorder affecting women An only X chromosome in pair 23 (sex chromosomes ) Clinical symptoms : Sterility and underdeveloped genitals Short height Frequency : 1 / 3300 birhts

7. Turner´s syndrome (XO):

8. Numerical abnormalities . TRISOMY Klinefelter´s syndrome (XXY): Disorder affecting men Two X chromosomes and one Y chromosome in pair 23 (sex chromosomes ) Clinical symptoms : Small genitals and sterility in some cases Mild learning disabilities Frequency : 1.4 / 1000 births

9. Klinefelter´s syndrome (XXY):

10. Numerical abnormalities . TRISOMY Triple X syndrome (XXX) = super female Disorder affecting women Three X chromosomes in pair 23 (sex chromosomes ) Clinical symptoms : Mild learning disabilities Delayed development of speech and motor skills Frequency : 1 / 1000 births

11. Triple X syndrome (XXX):

12. Numerical abnormalities . TRISOMY XYY syndrome : Disorder affecting men One X chromosome and two YY in pair 23 (sex chromosomes ) Clinical symptoms : Skeleton malformations ( very tall ) Moderate learning disabilities and aggressiveness Frequency : 1 / 2000 births

13. XXY syndrome :

14. Numerical abnormalities . TRISOMY Down´s syndrome : Disorder affecting women or men ( not sex- linked ) Three chromosomes in pair 21 Clinical symptoms : Varying degrees of intellectual disability Flat head syndrome ( brachycephaly ) Unusually small chin, skin folds at the edge of the eyes , round face , shorter limbs . Various problems with eyesight and heart . Frequency : 1.5 / 1000 births

15. Down´s syndrome :

16. Numerical abnormalities . TRISOMY Edwards´s syndrome : Disorder affecting women and men ( not sex- linked ) Three chromosomes in pair 18 Clinical symptoms : Severe intellectual disability Kidney and heart malformations Arrested growth and abnormal development of limbs Short neck and sternum Frequency : 1 / 6766 births

17. Edwards´s syndrome :

18. Numerical abnormalities . TRISOMY Patau´s syndrome : disorder affecting women and men ( not sex- linked ) Three X chromosomse in pair 13 Clinical symptoms : Intellectual disability Heart , genital, finger and brain malformations Missing palate Deformed feet Frequency : 1 / 4600 births

19. Patau´s syndrome :

20. Structural abnormalities Changes located in the structure of every single chromosome

21. Structural abnormalities Deletions :  A portion of the chromosome is missing or deleted.

22. Structural abnormalities Duplications :  A portion of the chromosome is duplicated, resulting in extra genetic material. 

23. Structural abnormalities Translocations :  A portion of one chromosome is transferred to another chromosome.

24. Structural abnormalities Inversions :  A portion of the chromosome has broken off, turned upside down, and reattached. As a result, the genetic material is inverted. 

25. References http://www.genome.gov/11508982#al-5 http://www.dnaftb.org/#classical http://learn.genetics.utah.edu/content/disorders/chromosomal/ Cabrera. A. et al. 2012. 4 ESO. Biology and Geology . Oxford Education