genetic disorders in human reproduction turner syndrome khalid esmail leslie newcombe nicola yang
TRANSCRIPT
GENETIC DISORDERS IN GENETIC DISORDERS IN HUMAN REPRODUCTIONHUMAN REPRODUCTIONTurner SyndromeTurner Syndrome
Khalid EsmailKhalid EsmailLeslie NewcombeLeslie Newcombe
Nicola YangNicola Yang
http://www.utsts.tk/http://www.utsts.tk/
Introduction
Also: Gonadal DysgenesisMost common sex chromosome abnormality in females– Occurs in 1 per 2,500 girls– Described by Dr. Henry Turner in
1938; chromosomal abnormality discovered in 1960
Normal: has two X chromosomes; 46 in allTurner syndrome: has a missing or damaged X chromosome in some/all cells; only 45 in all
Normal female karyotype
Karyotype with Turner SyndromeImages courtesy of North Central Regional Technology in Education Consortium
(http://www.ncrtec.org/tl/camp/gene/female.gif)
http://www.utsts.tk/http://www.utsts.tk/
CausesX-Chromosome Monosomy– Male gamete 22 autosomes (“regular” chromosomes) and one
sex chromosome.
(Monosomy: X-chromosome lost during meiosis of sperm)Normal cell division during meiosis
Monosomy: sex chromosome lost during sperm meiosis
All images courtesy of National Institute of Child Health and Human Development All images courtesy of National Institute of Child Health and Human Development Source: http://turners.nichd.nih.gov/ClinFrIntro.htmlSource: http://turners.nichd.nih.gov/ClinFrIntro.html
X-Chromosome Defects- Missing / damaged portion of X-chromosome-Results in small, large or no effects
- Some genes absent- Activate usually silent genes
http://www.utsts.tk/http://www.utsts.tk/
X-Chromosome MosaicismLost during the early stages of embryonic development– Some cells still have two, some only one – Effects not as evident
X-chromosome lost during embryonic
development
All images courtesy of National Institute of Child Health and Human All images courtesy of National Institute of Child Health and Human Development Development Source: Source: http://turners.nichd.nih.gov/ClinFrIntro.htmlhttp://turners.nichd.nih.gov/ClinFrIntro.html
Causes
http://www.utsts.tk/http://www.utsts.tk/
Diagnosis
Karyotyping– Chromosomal pattern– Only way to confirm
diagnosis
It is done…– Before birth:
amniocentesis or chorionic villous sampling
– After birth: blood test
Chorionic villous sampling: sample of placental tissue.
Image courtesy of http://www.nlm.nih.gov/medlineplus/ency/imagepages/9181.htm
http://www.utsts.tk/http://www.utsts.tk/
Identifying features & Symptoms
Problems with body development and body systems
Primary Features
- Ovarian Failure- Medical Problems- Short Stature
Growth curve comparing the average heights of girls without
TS, the average heights of girls with TS
and the average heights of girls with TS
that are not treated
Growth chart for children with Turner syndrome. Source: Rieser P, Davenport M. Turner Syndrome: A Guide for Families. Houston, TX: Turner Syndrome Society of the United States; 2002. Data derived from Lyon et al.
http://www.utsts.tk/http://www.utsts.tk/
Identifying Features:Secondary Features
Puffy hands and feet at birth
Webbed neck Prominent
Rotated Ears
Ptosis: drooping eyelids
Images courtesy of www.medscape.com/ viewarticle/445555_1, http://health.families.com/turner-syndrome-3417-3419-gem and http://www.nlm.nih.gov/medlineplus/ency/imagepages/1111.htm
Shield Chest
Nail dysplasia
Cubitus Valgus
Low posterior hairline
http://www.utsts.tk/http://www.utsts.tk/
Treatment
No known cure for chromosome abnormality
However,Injections of human growth hormones (HGH), estrogen, and progesterone – Trigger further
developmentHGH injection
Image courtesy of Image courtesy of http://www.hghforheight.com/injection.gifhttp://www.hghforheight.com/injection.gif
http://www.utsts.tk/http://www.utsts.tk/
Summary --- Conclusion • TS: Having damaged or missing portion of X- chromosome
• Three causes
• X- Chromosome Defects
•X- Chromosome Monosomy
•X- Chromosome Mosaicism
• Diagnosed with Karyotyping
• Many features/symptoms: ovarian failure, short stature etc.
• Not prone to mental retardation
• No cure for TS
• Injections of hormones may stimulate development