For example, if someone has contributed $10,000 post-tax and $30,000 pre-tax to a traditional IRA and wants to convert the post tax $10,000 into a Roth, the pro-rated amount (ratio of taxable contributions to total contributions) is taxable.or example, if someone has contributed $10,000 post-tax and $30,000 pre-tax to a traditional IRA and wants to convert the post tax $10,000 into a Roth, the pro-rated amount (ratio of taxable contributions to total contributions) is taxable.
A trisomy and a monosomy are types of numerical chromosome abnormalities that can cause certain birth defects. Normally, people are born with 23 chromosome pairs, or 46 chromosomes, in each cell â one inherited from the mother and one from the father.
These cell division abnormalities result in extra genetic material from chromosome 21, which is responsible for the characteristic features and developmental problems of Down syndrome. Any one of three genetic variations can cause Down syndrome: 1  Trisomy 21.2  About 95 percent of the time, Down syndrome is caused by trisomy 21 â the child has three copies of chromosome 21 (instead of the usual two copies) in all cells. Mosaic Down syndrome. 2  In this rare form of Down syndrome, children have some cells with an extra copy of chromosome 21. 3  This mosaic of normal and abnormal cells is caused by abnormal cell division after fertilization. 4  Translocation Down syndrome.