New York, April 29 (IANS) Researchers have identified four previously unknown genetic diseases that can be brought under the umbrella diagnosis of schizophrenia.

Cases associated with changes in each of the four genes were different from each other in terms of symptoms, intelligence level and other disease features, the researchers said.

"A common fallacy is that schizophrenia can be treated as a single disease," explained lead study author Dolores Malaspina from NYU Langone Medical Centre in New York.

"Our biologically driven study begins to answer longstanding questions in the field about why any two people diagnosed with schizophrenia may have drastically different symptoms. For the first time, we have defined four syndromes mechanistically,” Malaspina noted.

Patients with schizophrenia struggle to interpret reality, typically suffering from hallucinations, learning disabilities, emotional withdrawal and lack of motivation. 

In the current study, researchers analysed 48 ethnically diverse patients diagnosed with schizophrenia, looking at symptom sets in patients found to have rare or previously unknown changes in the DNA code of the four genes that disrupted brain function.

The four influential genes now tied by the study to specific conditions are all involved in the growth or regulation of nerve circuits. 

"Our results argue that new treatments should -- while addressing core psychoses -- also focus on processing speed in TGM5 cases, working memory in PTPRG, zinc augmentation in SLC39A13, and nerve cell protection in patients with ARMS/KIDINS220 mutations," first study author Thorsten Kranz, postdoctoral fellow at NYU Langone, said.

The findings appeared online in the journal EbioMedicine.

"Perhaps as many as 30 percent of schizophrenic patients may now become candidates for more precise treatment based on the individual characteristics of these four genes, with the remaining cases becoming less mysterious as we pull these groups out of the mix," Malaspina said.​