Numerical Abberations Flashcards
2 Major Categories of Chromosomal Abnormalities
- Numerical Abnormalities
- Structural Abnormalities
Defects involving an abnormality in the number of chromosomes
Numerical Abnormalities
Subclassifications of Numerical Abnormalities
ANEUPLOIDY
POLYPLOIDY
Condition of having a normal number of structurally normal
chromosomes
Euploidy
Any abnormal number of chromosomes that is not a multiple of the haploid number
Aneuploidy
Presence of an extra chromosome
Trisomy
Absence of a single chromosome
Monosomy
Cause of Aneuploidy
Non disjunction - Failure of chromosomes to separate normally
Chromosome number is higher than 46 but is
always an exact multiple of the haploid
Polyploidy
A karyotype with 69 chromosomes
Triploidy (3n)
A karyotype with 92
chromosomes
Tetraploidy (4n)
2 ways of Autopolyploidy
- Nondisjunction
- Meiotic nondisjunction
- Mitotic nondisjunction (occur in early embryo)
- Genome duplication
Cell with fewer than 46 chromosomes
Hypodiploid
Cells have from 23 up to approximately 34 chromosomes
Near-haploid
Cells have more than 46 chromosomes
Hyperdiploid
Chromosome number of more than 50
High hyperdiploidy
Disease Associations
Infertility and sterility
Intersexes
Multiple congenital malformations
Mental retardation
Types of Aneuploidy
Sex Chromosome Aneuploidies Autosomal Aneuploidies
Females
Turner syndrome (XO)
Metafemale (Triple- X)
Males
Klinefelter syndrome (XXY)
Jacob syndrome (XYY)
Which sex chromosomal aberrations are monosomy?
Turner Syndrome?
Turner syndrome is first described in year __?
1938
Turner syndrome is first described by ___?
Dr. Henry Turner
Turner syndrome occurs in ____
1 out of every 8,000 girls
Presence of an extra X chromosome in each cell of a human female
Triple-X, trisomy X, XXX syndrome, and 47,XXX
aneuploidy
47, XXY or XXY syndrome
Klinefelter’s Syndrome
Cite features of Triple X Syndrome
- Menstrual irregularities
- Learning Disabilities
Cite features of Turner Syndrome
- Short stature
- Lymphedema (swelling) of the hands and feet
- Rudimentary ovaries gonadal streak (underdeveloped gonadal structures)
- Shortened metacarpal IV (of hand)
- Small fingernails
- Characteristic facial features
- Webbed neck
47, XXY or XXY syndrome
Klinefelter’s Syndrome
Cite features of Klinefelter’s Syndrome
Gynecomastia
Weaker bones
Low energy levels
Smaller testicles & penis
Delayed puberty
Less facial & body hair
47, XYY syndrome
Jacob’s Syndrome
Cite features of Jacob’s Syndrome
- Normal appearance -> tall stature
- Increased vulnerability to ADHD
(attention deficit hyperactivity disorder) - Learning disabilities
- Increased vulnerability to autistic spectrum disorders
- Eyes set slightly far apart
- Large head
- Infertility
Autosomal Numeric Aberration
- Down Syndrome
- Edward Syndrome
- Patau Syndrome
- Warkany Syndrome
Trisomy 21, Trisomy G
Down Syndrome
Down Syndrome is named after Doctor ___?
John Langdon Down
Down Syndrome is named in the year ___?
1866
Cite features of Down Syndrome
- Microgenia (an abnormally small chin)
- Unusually round face
- Macroglossia (protruding or oversized tongue)
- Almond shape to the eyes caused by an epicanthic
fold of the eyelid - Shorter limbs
- Poor muscle tone
- Larger than normal space between the big and
second toes
Trisomy 18 / Trisomy E is known as?
Edwards Syndrome
Trisomy 18 / Trisomy E results from?
heart abnormalities,
kidney malformations, and other internal organ disorders
Cite features of Edwards Syndrome
Low birthweight
* Small, Abnormal shaped head
* Small jaw and mouth
* Long fingers that overlap, with
underdeveloped thumbs and clenched fists
* Low-set ears
* Smooth feet with rounded soles
* Cleft lip and palate
Trisomy 13 is also known as?
Patau Syndrome
Cite features of Patau Syndrome
- Small head size
- Extra toes or fingers
- Cleft lip or palate
- Heart defects
- Holoprosencephaly à the brain doesn’t divide
into two halves; Severe mental retardation - Nasal malformation
- Hypotelorism (reduced distance between the
eyes) or cyclops
Trisomy 8 is also known as
Warkany Syndrome
Cite features of Patau Syndrome
- Characteristic facial features:
- Elongation of the skull (scaphocephaly)
- Prominent forehead
- Widely-spaced eyes
- Deeply set eyes
- Broad upturned nose
- Brain malformations
- Highly arched or cleft palate
- Shortened neck with extra skin folds
- Long slim body with a narrow chest, shoulders, and pelvis
- Kidney and cardiac abnormalities
