Jérôme Jean Louis Marie Lejeune

John Langdon Down

Raymond Alexander Turpin

John Cyprian Phipps Williams

Chromosomes fail to separate properly, resulting in a nondisjunction where an extra copy of Chromosome 21 is created (3 "21" Chromosomes), which leads to Down Syndrome.

Chromosome 21 attaches to another Chromosome, resulting in a structural abnormality that causes Down Syndrome.

After fertilization, one line of cells replicates properly, whereas the other line replicates improperly, with an extra Chromosome 21, which results in Down Syndrome.

None of the Above.

Chromosomes fail to separate properly, resulting in a nondisjunction where an extra copy of Chromosome 21 is created (3 "21" Chromosomes), which leads to Down Syndrome.

Chromosome 21 attaches to another chromosome, resulting in a structural abnormality that causes Down Syndrome.

After fertilization, one line of cells replicates properly, whereas the other line replicates improperly, with an extra Chromosome 21, which results in Down Syndrome.

None of the Above.

Chromosomes fail to separate properly, resulting in a nondisjunction where an extra copy of Chromosome 21 is created (3 "21" Chromosomes), which leads to Down Syndrome.

Chromosome 21 attaches to another chromosome resulting in a structural abnormality that causes Down Syndrome.

After fertilization, one line of cells replicates properly, whereas the other line replicates improperly, with an extra Chromosome 21, which results in Down Syndrome.

None of the Above.

Chorionic Villus Sampling (CVS)

Amniocentesis

Percutaneous Umbilical Cord Blood Sampling (PUBS)

All of these.

70 years and above.

9-12 years of age.

30-70 years of age, contingent upon factors.

None of these.

Near-sightedness and crossed eyes.

Cataracts

Brushfield Spots

Simian Crease

All of the Above.

Only cataracts, near-sightedness, cross eyes, and brushfield spots.

Chromosome 27

Chromosome 21

Chromosome 23

Chromosome 25

45

47

46

It is not yet known.

Spectrum Stabilization; Vision therapy, occupational therapy, motor therapy, etc.

Early Intervention; Vision therapy, occupational therapy, motor therapy, etc.

Spectrum Stabilization; Physical Therapy, Speech-Language Therapy, Occupational Therapy, Emotional and Behavioral Therapy, etc.

Early Intervention; Physical Therapy, Speech-Language Therapy, Occupational Therapy, Emotional and Behavioral Therapy, etc.