Final answer:
The chromosomal condition of an individual with Patau syndrome is described as diploid with a trisomic aneuploidy of chromosome 13, causing a genetic imbalance and developmental issues.
Step-by-step explanation:
The chromosomal condition of an individual with Patau syndrome can be described as aneuploid, specifically, trisomy. Patau syndrome is the result of an extra copy of chromosome 13 in the cells of the individual, which means they have three copies of this chromosome instead of the typical two. Therefore, the correct answer is diploid with three copies (or an extraneous copy) of chromosome 13.
Individuals with Patau syndrome have a genetic imbalance due to this extra chromosome, which leads to a wide variety of developmental problems. Humans are normally diploid with 22 pairs of autosomes and one pair of sex chromosomes, and any variation from this is considered aneuploid. Patau syndrome, like other trisomy conditions such as Down syndrome (trisomy 21), is a type of aneuploidy.