Chromosomal Abnormalities Flashcards
Type of myxoploidy that came from the same zygote
Mosaicism
Causes of chromosomal abnormality
- misrepair in broken chromosome
- improper recombination
- malsegregation during mitosis and meiosis
Cause by Abnormal fertilization. Abnormal event during early embryo
Constitutional abnormalities
Not all cells are affected
Acquired or somatic abnormalities
Complete sets of chromosomes. Good set
Euploid
Multiple cell line coming from different zygote
Chimerism
Missing pair of homologs
. Chromosome 6
Nullisomy
One chromosome are missing
Monosomy
Extra chromosome
Trisomy
Example of polyploidy
Mosaic triploidy
All cells are affected
Constitutional abnormalities
Failure of paired chromosome to separate during anaphase 1
Nondysjunction
Nondysjunction in meiosis
Trisomic
Monosomic
Inverted segment is on the long or short arm. Do not involve the centromere
Paracentric
Nondysjunction in mitosis
Mosaicism
Result of a delayed movement during anaphase
Anaphase lag
This substance recognize and repair broken chromosome ends
Enzymes
Prevent cells with unpaired chromosome breaks from entering mitosis
Cell cycle checkpoint mechanism
An extra chromosomal segment within the same homologous chromosomes
Duplication
Example of duplication wherein chromosome 17 duplicates
Charcot marie tooth disease type 1A
Ring chromosome 13&14
Mental retardation
Dysmorphic facial features
Portion of the chromosome has broken off turned upside down and reattached
Inversions
Loss of a segment of a chromosome
Deletion
Telomere is missing
Terminal deletion
Two arms have fused together to form a ring
Ring chromosome
Ring chromosome 20
Epilepsy
Ring X chromosome
Turner syndrome
What causes ring chromosome
Deletion of two telomeres
Dense staining structure seen in the nuclei of a female mammals
Barr body
Missing or extra chromosome
Not a good set
Aneuploidy
Structural rearrangement involving 2 non homologous chromosomes
Translocation
Two segments from two different chromosome have been exchanged
Reciprocal translocation
Involves reciprocal transfer of the long arms of two acrocentric chromosome
Robertsonian translocation
Inactivated X chromosome
Barr body
Diagram for a family tree
Pedigree
Shape for male? Female? Unknown?
Male-square
Female-circle
Unknown-diamond
Parents are connected via
Horizontal lines
Parents to offspring
Vertical line
Connect siblings
Sibship line
Arrangement of siblings
Left to right
Oldest to youngest
Siblings are numbered using
Arabic numerical
Generation are numbered using
Roman numerals
Horizontal line with diagonal line
Monozygotic or identical twin
Diagonal line without horizontal
Dizygotic or fraternal twins
Question trait truly expressed by the individual
Fully shades
Half filled
Carrier
Adopted child
Broken lines
Single abnormal allele is sufficient to cause disease despite the presence of normal allele
Autosomal dominant disease
Autosomal dominant trait with complete penetrance
Achondroplasia
Achondroplasia is the most common cause of?
Dwarfism
Negative regulatory effect of bone growth
Fibroblast growth factor receptor gene 3
Hereditary motor and sensory neuropathy
Charcot Marie tooth disease
CMT type 1a is defect in what chromosome?
17p
Individual who has inherited two abnormal alleles at a given locus by receiving one mutant allele from each carrier parents
Autosomal recessive disease
Percentage of hereditary if both parents are carriers
25% normal
50% carrier
25% affected
Most common fatal autosomal recessive disorder in caucasian population
Cystic fibrosis
A multisystem disorder affecting the cells that produce mucus, sweat, saliva and digestive juices
Cystic fibrosis
CF gene is located in
7q
Characterized by excess iron deposition in otherwise healthy tissue
Hereditary hemochromatosis
Regulates the amount of iron absorbed from food
Hemochromatosis type 1 gene
Mutant allele resides on the X chromosome
X linked disease
Carriers of X linked disease with one normal and one mutant but typically not affected
Females
Received mutant allele from the mothers
Male
Carrier female of X linked disease has?
25% transmitting normal allele to son
25% affected son
25% transmitting normal allele to daughter
25% affected daughter
An X linked recessive bleeding disorder caused by a deficiency of factor VIII
Hemophilia A
Gene in hemophilia A is located in
Xq28
Characterized by progressive skeletal muscle wasting
Duchenne muscular dystrophy
Chromosome in Duchenne muscular dystrophy
Xp21
One of the most common inherited from mental retardation
fragile X syndrome
Expansion of CGG repeats
Fragile x syndrome
Full mutations in fragile x
> 200 CGG repeats
Chromosome has lost one of its arms and this arm is replaced with an exact copy of a chromosome segment including the centromere
Isochromosome
Ring chromosome 15
Mental retardation
Dwarfism
Microcephaly
Resulting to invisible alteration in chromosomes
Chromosomal abnormality
Breaks occur in both short and long arms. Inverted segment include the centromere
Pericentric
Multiple chromosome set.
Abnormal genetic event
Polyploidy