Name:
Chromosomal Nondisjunction Disorders worksheet
Read the following descriptions of chromosomal nondisjunction disorders. Then study the descriptions of the following
fictitious patients. Diagnose each patient’s chromosomal disorder by filling in the blanks below.
Down syndrome: Patient has 47 chromosomes (one extra 21st chromosome). Some characteristics are short broad
hands, short height, broad head, round face, large tongue, slanting eyes, and may have cognitive
disabilities.
Edward’s syndrome: Patient has 47 chromosomes (one extra 18th chromosome). Some characteristics are low set and
malformed ears, small mouth and nose, malformed organs, cognitive disabilities, and low survival rate
after 6 months of age.
Klinefelter’s syndrome: Patient has 47 or 47+ chromosomes (one to several extra X and Y chromosomes); male. Some
characteristics are small testes, female-like breasts, sterility, female-like voice, and developmental
disabilities.
Patau’s syndrome: Patient has 47 chromosomes (one extra 13th chromosome). Some characteristics are deafness, cleft
lip/palate, may have cognitive disabilities, and low survival rate after 3 months of age.
Turner’s syndrome: Patient has 45 chromosomes (one of the sex chromosomes is missing, often classified as X0); female.
Some characteristics are short stature, swelling, broad chests, congenital heart disease, low hairline,
low set-ears and webbed necks.
Extra Y chromosome: Patient has 47 chromosomes (one extra Y chromosome); male. Some characteristics are tall
height, tendency of aggressiveness in behavior and may have cognitive disabilities.
1. _______________________ Infant A (1 month old) has a cleft palate and does not respond to sound. She also
appears to have a heart problem.
2. _______________________Child B (12 years old) is short for his age and shows mental retardation. His
appearance is characterized by slanting eyes. He has a hard time keeping his mouth closed, partially due to a
large tongue.
3. _______________________Patient C (42 years old) is currently in jail for property damage. He is 6 ft 5 inches
and has been diagnosed as being developmentally delayed.
4. _______________________Patient D (18 years old) shows many female characteristics. His voice is high, he
has little body hair, and shows some breast development. He is not able to produce offspring.
5. ______________________Patient E (4 months old) has a small nose and mouth. Her ears are considered to
not be of normal shape. She also has several internal problems, and is having difficulty with cognitive
abilities.
6. _____________________Patient F (6 years old) has a webbed neck and a broad chest. She needs medication
for her heart defect, which helps with her circulation.