1q21.1 deletion syndrome
1q21.1 deletion syndrome is a rare aberration of chromosome 1. A human cell has one pair of identical chromosomes on chromosome 1. With the 1q21.1 deletion syndrome, one chromosome of the pair is not complete, because a part of the sequence of the chromosome is missing. One chromosome has the normal length and the other is too short.
| 1q21.1 deletion syndrome | |
|---|---|
| Other names | Chromosome 1q21.1 microdeletion syndrome, 1q21.1 microdeletion, Monosomy 1q21.1, Del(1)(q21), 1q21.1 contiguous gene deletion, 1q21.1 deletion, Chromosome 1q21.1 deletion syndrome, Chromosome 1q21.1 deletion syndrome, 1.35-Mb. |
| Specialty | Genetics. |
| Symptoms | Delayed development, intellectual disability, physical abnormalities, neurological abnormalities and psychiatric problems. |
| Usual onset | Infancy. |
| Causes | Deletion of genetic material on the long arm (or q arm) of chromosome 1 at position 21.1. |
| Diagnostic method | Chromosomal microarray analysis. |
| Differential diagnosis | 22q11.2 microdeletion syndrome. |
| Frequency | 0.015% of the population. |
In 1q21.1, the '1' stands for chromosome 1, the 'q' stands for the long arm of the chromosome and '21.1' stands for the part of the long arm in which the deletion is situated.
The syndrome is a form of the 1q21.1 copy number variations, and it is a deletion in the distal area of the 1q21.1 part. The CNV leads to a very variable phenotype, and the manifestations in individuals are quite variable. Some people who have the syndrome can function in a normal way, while others have symptoms of intellectual impairment and various physical anomalies.
1q21.1 microdeletion is a very rare chromosomal condition. Only 46 individuals with this deletion have been reported in medical literature as of August 2011.