A rare short allele of the serotonin transporter promoter region (5-HTTLPR) found in an aggressive schizophrenic patient of Jewish Libyan origin.

The serotonin transporter gene (SLC6A4), which plays a key role in the serotonergic pathway in the brain, is a candidate for mediating genetic susceptibility to various psychiatric disorders. There are two predominant alleles in the polymorphic promotor region [5-HT transporter gene-linked polymorphic region (5-HTTLPR)] of this gene: a long and a short allele with 16 and 14 repeat units, respectively. The short allele has lower activity and is associated with several psychiatric disorders and personality traits. We identified and sequenced a novel allele with 13 repeat units, 23 base pairs shorter than the common short allele. This unique allele was detected in a schizophrenic patient of Jewish Libyan origin. The patient exhibited extreme aggressive behavior and committed suicide after several attempts. The novel short allele was not detected in 172 healthy control subjects and 361 patients with various mental disorders. The presence of a very short unique allele in a severely aggressive schizophrenic patient may reflect a specific effect on the particular phenotype, although it is unlikely that this allele has a major contribution to susceptibility to schizophrenia. The role of the allele in serotonin transport and possible association with disease phenotype should be further investigated.