⚖️ Structural Chromosomal Abnormalities ⚖️

Question 1

Robertsonian Translocation

Answer 1

Occurs between acrocentric chromosomes like 13, 14, 15, 21, 22, leading to fusion of long arms and loss of short arms, often associated with Down syndrome.

Question 2

22q11.2 Deletion Syndrome

Answer 2

Also known as Velocardiofacial or DiGeorge syndrome, it is a common genetic disorder characterized by a deletion on chromosome 22q11.2. Patients may exhibit heart defects, learning disabilities, and facial anomalies.

Question 3

Cri-du-chat Syndrome

Answer 3

A genetic disorder caused by a deletion on chromosome 5p, resulting in a high-pitched cry resembling a cat’s meow. Patients may also experience intellectual disability and distinctive facial features.

Question 4

Inversions

Answer 4

Structural abnormalities involving changes in the banding pattern of chromosomes, can be pericentric or paracentric.

Question 5

Ring chromosomes

Answer 5

Formed when chromosome ends fuse to create a ring-like structure, associated with genetic abnormalities.

Question 6

Microdeletion Syndrome

Answer 6

Genetic disorders caused by small deletions of chromosomal regions, examples include cri-du-chat, 22q11.2 DS, Wolf-Hirschhorn, Prader-Willi, and Angelman syndromes.

Question 7

Uniparental disomy

Answer 7

Inheritance of both chromosomes from the same parent, leading to genetic abnormalities.

Question 8

Isochromosomes

Answer 8

Chromosomes where one arm is lost and the other arm is duplicated, leading to genetic imbalance.

Question 9

Balanced rearrangements

Answer 9

Chromosomal rearrangements that maintain equal genetic material, can lead to unbalanced rearrangements in offspring.

Question 10

Structural Chromosomal Abnormality

Answer 10

Refers to changes in the structure of chromosomes which can lead to genetic disorders.

Question 11

Aneuploid Syndromes

Answer 11

Refer to conditions like Down syndrome, Turner syndrome, and 22q11.2 deletion syndrome caused by abnormal chromosome numbers.

Question 12

Robertsonian Translocation

Answer 12

A chromosomal abnormality where the long arms of two acrocentric chromosomes fuse together, causing a translocation. It can result in genetic disorders like Down syndrome.

Question 13

Deletions in Chromosome 15q11-13

Answer 13

Deletions in this region can lead to syndromes like Prader-Willi and Angelman, affecting genes like SNRPN and UBE3A. These deletions can be associated with specific clinical features.

Question 14

Trisomy rescue mechanism

Answer 14

Occurs when a zygote tries to correct a trisomy by kicking out the excess chromosome.

Question 15

Reciprocal Translocation

Answer 15

Involves an exchange of genetic material between non-homologous chromosomes, which can result in no effects, cancer transformation, or increased risks of spontaneous abortions.

Question 16

Cytogenomic Tests

Answer 16

Diagnostic tests like karyotype, FISH, and microarray CGH used to detect chromosomal aberrations in patients.

Question 17

Microdeletion Syndromes

Answer 17

Genetic disorders caused by a small deletion of a chromosomal segment, often leading to distinct clinical features. Detection can be done using techniques like FISH and microarray CGH.