Turners : Turners
Slide 2 : Cause
Turner syndromes have one X chromosome
Due to non-disjunction of sex-chromosome
The females are born with 44 + XO condition.
Epithelial cells of these patients are X chromatin negative as expected when only one X chromosome in parents.
Frequency
Occurs in about 1 per 2500 live female births.
More than 90 percent abort spontaneously.
A rough estimate for 45, X adults in the general population is 1 in 5000.
Super Female or X Polysomy : Super Female or X Polysomy With more number of X-chromosomes.
They give birth to normal children.
One would expect that fertile triple X women would produce children of whom half would be XXY or XXX and half would be normal.
So far, however, not a single XXX or XXY child among the progeny of XXX women has been found.
This probably the result of preferential segregation; the XX-containing secondary oocyte becomes a polar body and the X-containing secondary oocyte becomes the ovum births.
Slide 4 : Characteristics
Most of them (females) show intellectual impairment.
Some show amenorrhea (no neustrual cycle) although sexual development is normal.
XXXX and XXXXX are rare and may have multiple congenital abnormalities like dwarfism and mental deficiency.
Cause
Non disjunction of sex chromosomes during meions. Super Female
Slide 5 : Chromosome compliment
In these persons, two Barr are seen in the nuclei of buccal smears.
They have 47 chromosomes instead of normal 46 and the sex-chromosome constitution is assumed to be XXX.
Some may even have XXXX or XXXXX (very rare) with three and for bar bodies respectively. It is observed that if the higher is the number of X chromosomes, the greater the degree of mental retardation.
Frequency
The incidence is about 1/1200 the female born. Super Female
What is Klinefelter's Syndrome ? : What is Klinefelter's Syndrome ? Genetic disorder of sterile male
Was described the year 1942 by Dr. Harsy Klinefelter and his co-workers.
Slide 7 : Symptoms
Persons are phenotypically male
Sterile males
Though genitalia are under developed
Body hair is less
Develop breasts called gynecomastia.
Have long legs and arms.
With soft testis and no sperms.
Slide 9 : Cause
Due to non-disjunction of sex chromosome during gamete formation chromosome compliment
Males with Klinefelter syndrome have 47 chromosome with XXY condition.
Presence of one Barr body in them indicates that they have two bar X chromosome.
Frequency
One is about 500 'male' births produces an individual with suels abnormalities. Klinefelter's Syndrome
Supermales : Supermales Tall males
With more Y chromosomes
Such males were seen first in 1965 a Scottish prison.
Slide 11 : Characteristics
1. Tall males and more gangly than normal individuals.
2. They exhibit aggressive and antisocial behaviour.
3. These males are fertile.
Their meiosis is of XY type as extra Y is not transmitted and their gametes contain either X or Y and never XY or YY.
Slide 12 : Causes
Occur due to non-disjunction of sex chromes in normal individuals.
Chromosome compliment
They have simple X chromosome and extra Y chromosome thus have 47 chromosomes (44 + XYY)
Frequency
1/500 individuals (males) born. Supermales
Supermales : Supermales
Aneuploid Abnormalities in the Human Population : Aneuploid Abnormalities in the Human Population Chromosomes Syndrome Frequency at Birth
AUTOSOMES
Trisomic 21 Down 1/700
Trisomic 13 Patau 1/5,000
Trisomic 18 Edwards 1/10,000
SEX CHROMOSOMES IN FEMALES
XO, monosomic Turner 1/5,000
XXX, trisomic
XXX, tetrasomic 1/700
XXXXX, pentasomic
SEX CHROMOSOMES IN MALES
XYY, trisomic Normal 1/1000
XXY, trisomic
XXYY, tetrasomic Klinefelter 1/500
XXXy, tetrasomic
XXXXY, pentasomic
XXXXXY, hexasomic
Rh incompatibility : Rh incompatibility The Rh system of blood classification is so named because it was first worked out in the blood of the Rhesus monkey.
Like the ABO grouping, the Rh system is based on antigens on the surfaces of erythrocytes.
People whose RBCs have the Rh agglutinates (D antigens) are designated Rh+.
Those who lack Rh agglutinates are designated Rh- GENE INCOMPATABILITIES
Slide 16 : Normally, plasma does not contain anti-Rh agglutinins.
However, if an Rh- person receives Rh+ blood, the body starts to make anti-Rh agglutinins that will remain in the blood.
If a second transfusion of Rh+ blood is given later, the previously formed anti-Rh agglutinins will cause hemolytic of the donated blood, and a severe reaction may occur.
EBF : EBF
HEMOLYTIC DISEASE OF THE NEWBORN : HEMOLYTIC DISEASE OF THE NEWBORN The most common problem with Rh incompatibility
A small amount of Rh+ blood leaks from the fetus through the placenta into the bloodstream of an Rh-mother, the mother will start to make anti-Rh agglutinins.
Anti-Rh agglutinins can cross the placenta and make their way into the bloodstream of the fetus.
If the fetus is Rh- what would happen ? : If the fetus is Rh- what would happen ? There is no problem
Since Rh- blood does not have the Rh agglutinogen.
When mother is Rh -ve and the foetus is Rh +ve anti Rh agglutinin crosses the placents from the mother into the blood stream of the foetus causing haemolysis known as Erythroblastosis foetalis (EBF) : When mother is Rh -ve and the foetus is Rh +ve anti Rh agglutinin crosses the placents from the mother into the blood stream of the foetus causing haemolysis known as Erythroblastosis foetalis (EBF)
And If the fetus is Rh+ then…….? : And If the fetus is Rh+ then…….? Hemolysis may occur in the fetal blood.
Brought on by fetal-maternal incompatibility is called hemolytic disease of the new-born (HDN)
Also called erythroblastosis fetalis.
Slide 22 : Can this be prevented ?
Yes
By giving all Rh-mothers an injection of an anti-Rh gamma globulin preparation (RhoGAM)
Soon after delivery, miscarriage, or abortion.
ABO incompatibility : ABO incompatibility
Slide 24 : Transfusion problems that can result from the ABO system
If red blood cells with B antigens (from type B individuals) are transfused to type A individuals
The type B cells will be attacked and eliminated by the anti-B antibodies present in the type A individuals
Polydactyly : Polydactyly Of the several dominant traits in human, polydactyly is one of the autosomal traits.
People born with such disorders show extra fingers or toes
Polydactyly : Polydactyly
Slide 27 : Abnormally broad and short fingers in human in persons
The first person to document a Mendelian trait in humans was W. Farabee in 1905
One could pass this abnormality to the next generation over several generations.
A dominant trait What do you mean by brachydactyly ?
Syndactyly : Syndactyly corrected !
Marfan's syndrome : Marfan's syndrome Not all inherited human diseases produce crippling abnormalities.
For example,
Marfan syndrome is produced by a dominant allele
Alters skeletal structure and connective tissues.
Slide 30 : Tend to have long, thin limbs, rubbery joints, narrow chests, displacement of the eye lens, abnormal heart valves and often develop an aneurysm of the aorta.
Not immediately lethal symptoms
Many live into their fifties and sixties
Often dying of heart failure or rupture of the aorta.
Syndrome related to a reduction in production of fibrillin, (protein that supports the elastic fibers in normal tissues). Marfan syndrome
Marfans : Marfans
Thought to be….. : Thought to be…..