Question

Which type of aneuploidy results in a total of 45 chromosomes?

Options

• Trisomy (2n + 1)

• Nullisomy (2n − 2)

• Monosomy (2n − 1)

• Tetrasomy (2n + 2)

Answer 1

Monosomy (2n − 1) results in 45 chromosomes, representing the loss of one chromosome from a homologous pair. Most monosomy conditions are lethal, except for Turner's Syndrome (45, XO), which is the only viable monosomy in humans. The loss of chromosomal material typically causes severe developmental abnormalities.