30 Questions
What is the term used to describe a condition where the chromosome complement is an exact multiple of the haploid number (23)?
Polyploidy
Which of the following conditions involves an abnormal number of chromosomes that is not an exact multiple of the haploid number (23)?
Down syndrome
Approximately what percentage of spontaneous abortions with a chromosomal abnormality involve triploidy?
20%
Which of the following statements about triploids is true?
Few triploids survive to term, and those that do usually have a quick demise.
What is the estimated incidence of autosomal aneuploidy in newborns?
0.2%
Which of the following is NOT an example of a cytogenetic abnormality?
Cystic fibrosis
What is the cause of Turner syndrome?
Nondisjunction of the X chromosome
What genetic condition leads to male hypogonadism?
Klinefelter syndrome (47, XXY)
What is the key factor determining male sex?
Single Y chromosome
Which scenario is most likely to result in mental retardation?
Higher number of X chromosomes in males and females
What is a common characteristic of sex chromosome disorders?
Subtle, chronic problems relating to sexual development and fertility
How can Turner syndrome be diagnosed?
Absence of Barr bodies in buccal smear
What is the main cause of aneuploidy shown in the image?
Failure of homologous chromosomes to separate during meiosis I
What is the consequence of a gamete with an abnormal chromosome number fusing with a normal gamete?
A zygote with monosomy or trisomy
Which of the following aneuploidies is generally lethal?
Monosomy of an autosomal chromosome
Which of the following trisomies is the most common chromosomal disorder in humans?
Trisomy 21 (Down syndrome)
What is a major risk factor for having a child with Down syndrome?
Advanced maternal age
Which of the following statements about sex chromosome aneuploidies is true?
They are generally compatible with life
What is the approximate incidence of Trisomy 18 (Edwards' Syndrome)?
1 in 8,000 live births
Which of the following physical abnormalities is characteristic of Edwards' Syndrome?
Rocker-bottom feet
What is the most common sex affected by Trisomy 18?
Females
Which of the following is a characteristic feature of Patau's Syndrome (Trisomy 13)?
Cyclopia (single central eye)
Which statement regarding sex chromosome abnormalities is correct?
Only one X chromosome is active due to lyonization
What is the approximate survival rate for infants with Trisomy 18 (Edwards' Syndrome)?
Few survive beyond 1 year of age
What is the primary characteristic of Klinefelter's syndrome?
Having 47 chromosomes (XXY) or 48 (XXXY)
Which of the following is NOT a symptom of Klinefelter's syndrome?
Increased muscle mass
What is the incidence of Klinefelter's syndrome?
1 in 500 males
What is the primary characteristic of XXX syndrome (Superfemale)?
The presence of a third X chromosome in a female
What is the primary characteristic of XYY syndrome?
The presence of an extra Y chromosome in a male
What is the cause of Fragile X syndrome?
An unusually large number of repeat nucleotide triplets near the tip of the X chromosome
Test your knowledge on cytogenetic disorders and numerical abnormalities. Learn about aneuploidy, polyploidy, somatic mosaicism, gonadal mosaicism, Down syndrome, Patau syndrome, Edward syndrome, Turner syndrome, Kleinfelter syndrome, and other chromosomal disorders.
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