Mrs Jones' First Consultation Flashcards
List the 7 types of congenital abnormalities and birth defects.
Malformation Disruption Dysplasia Sequence Association Deformation Syndrome
Define dysplasia
Abnormal organisation of cells into tissue
What is the most common cause of Sequence e.g. Potter Sequence?
Oligohydramnios – reduced supply of amniotic fluid
What are the 3 types of chromosome?
Metacentric
Submetacentric
Acrocentric
Describe how chromosome banding works.
Starts at 11 at the centromere – different banding for different stains
What are the three different types of chromosomal abnormality?
Aneuploidy Structural Mosaicism
What is mosaicism?
The cells of an individual do not all contain identical chromosomes. There may be two or more genetically different populations of cells. E.g. one cell lineage will be Down Syndrome
What is the difference between a balanced and unbalanced translocation?
Unbalanced – there is a loss of genetic material
What could be the potential future issues for someone who has a balanced translocation?
Balanced translocations lead to the formation of quadravalents (rather than bivalents) during meiosis which can lead to strange exchanges in genetic material which can cause disease
List some clinical features of Down Syndrome
Excess nuchal skin, sleepy, severe hypotonia, Single palmar crease, sandal gap Upwards slanting eye folds, macroglossia, Short stature, Cardiac abnormalities – ASD and VSD
List three possible causes of Down syndrome.
Non-disjunction during meiosis I or meiosis II
Robertsonian translocation –2 acrocentric chromosomes break at the centromere and fuses to form a new chromosome
Mosaicism
Name two other trisomy disorders
13 – patau syndrome, 18 – Edwards
What is monosomy X in females and what are the clinical features?
Turner Syndrome – webbed neck, infertile, normal intelligence, low posterior hairline
What is polysomy X in males and what are the clinical features?
Kleinfelter’s syndrome – tall, gynaecomastia, infertile, learning disability
How can someone who has sex chromosomes XX be male?
Due to a translocation in which the sex determining region on the Y (SRY) has been translocated onto the X chromosome.
