Isochromosomes

Isochromosomes are created by the incorrect divides of centromere.
 * Normally centromere divides vertically. In this case they divide horizontally.
 * The result is usually the lost of one arm. It means that newly created chormosome has just two long arms or two short arms which are normally connected by centromere.
 * We could find it on X chromosome very often.
 * It is a huge problem during the fertilization. Because fetus then get a trisomy for one arm and a monosomy for the second arm.

Related articles

 * Chromosome abnormalities