BIO 151 Assignment Questions and Answers

ASSIGNMENT QUESTION (As Sent)
WRITE NOTES ON

1. TRISOMIES
2. CRI DU CHAT SYNDROME
3. WOLF-HIRSCHON SYNDROME
4. VELOCARIOFACIAL SYNDROME
5. PRADA-WILLI SYNDROME
6. ANGEL-MAN SYNDROME
7. SEX CHROMOSOME ANUEPLOIDY

ASSIGNMENT
WRITE 3 MAJOR SYMPTOMS OF EACH OF THE TRISOMIES

Answer

NOTES ON GENETIC DISORDERS

1. Trisomies

Trisomy refers to a genetic condition where an individual has three copies of a particular chromosome instead of the normal two. It occurs due to nondisjunction during meiosis and can lead to developmental and health issues. Common trisomies include:

• Trisomy 21 (Down Syndrome) – Extra chromosome 21.

• Trisomy 18 (Edwards Syndrome) – Extra chromosome 18.

• Trisomy 13 (Patau Syndrome) – Extra chromosome 13.

2. Cri du Chat Syndrome

Cri du Chat syndrome (“Cry of the Cat”) is a rare genetic disorder caused by a deletion on the short arm of chromosome 5 (5p-). It is named after the characteristic high-pitched cry of affected infants, resembling a cat’s cry.

• Symptoms: Intellectual disability, delayed development, small head size (microcephaly), and distinct facial features.

3. Wolf-Hirschhorn Syndrome

Wolf-Hirschhorn syndrome (WHS) is a genetic disorder caused by a deletion in the short arm of chromosome 4 (4p-). It affects physical and mental development.

• Symptoms: Distinct facial appearance (Greek warrior helmet face), seizures, and severe developmental delay.

4. Velocardiofacial Syndrome (DiGeorge Syndrome)

Velocardiofacial syndrome, also known as 22q11.2 deletion syndrome, occurs due to a missing segment on chromosome 22. It affects multiple body systems.

• Symptoms: Heart defects, cleft palate, and immune system problems.

5. Prader-Willi Syndrome (PWS)

Prader-Willi syndrome is a genetic disorder caused by the loss of function of paternal genes on chromosome 15 (15q11-q13). It is associated with excessive eating and developmental delays.

• Symptoms: Poor muscle tone (hypotonia) in infancy, excessive hunger (hyperphagia), and intellectual disabilities.

6. Angelman Syndrome (AS)

Angelman syndrome is a neurodevelopmental disorder caused by the loss of function of the maternal gene on chromosome 15 (15q11-q13). It affects movement, behavior, and communication.

• Symptoms: Severe speech impairment, frequent laughter/happy demeanor, and ataxia (problems with movement and coordination).

7. Sex Chromosome Aneuploidy

Sex chromosome aneuploidy occurs when an individual has an abnormal number of sex chromosomes (X and Y). Some common conditions include:

• Turner Syndrome (45,X) – Affects females with one missing or incomplete X chromosome.

• Klinefelter Syndrome (47,XXY) – Affects males with an extra X chromosome.

• Jacob’s Syndrome (47,XYY) – Affects males with an extra Y chromosome.

B. 3 MAJOR SYMPTOMS OF EACH TRISOMY

1. Trisomy 21 (Down Syndrome)

• Intellectual disability

• Characteristic facial features (flat face, upward-slanting eyes)

• Hypotonia (low muscle tone)

2. Trisomy 18 (Edwards Syndrome)

• Severe intellectual disability

• Clenched fists with overlapping fingers

• Heart defects

3. Trisomy 13 (Patau Syndrome)

• Severe brain and facial abnormalities (cleft lip/palate, small head)

• Extra fingers or toes (polydactyly)

• Congenital heart defects

These genetic conditions vary in severity, and early diagnosis helps in managing symptoms effectively.