Objective To explore the change of serum insulin-like growth factor-2 (IGF-2) and its relationship with clinical characteristics in patients with schizophrenia. Methods Fifty-one schizophrenic patients were recruited in the present study and 50 healthy volunteers served as controls. The serum IGF-2 level was measured using enzyme linked immunosorbent assay (ELISA). Positive and Negative Syndrome Scale (PANSS) was used to evaluate the psychotic symp?toms of patients. Trail Making Test-A (TMTA), Digit-Symbol Coding Test (DSCT), Continuous Performance Test (CPT) and Stroop Color-Word Test (SCWT) were used to evaluate the cognitive function of both groups. Results There were sig?nificant differences in the results of TMTA, DSCT, CPT and SCWT between patient and control groups. The serum levels of IGF-2 were significantly lower in patients than that in controls [(202.7±40.7) ng/mL vs. (365.9±65.5) ng/mL, P<0.01]. The levels of serum IGF-2 were not significantly different between first-episode and recurrent schizophrenic patients (P>0.05). Furthermore, significant correlations were found between the serum IGF-2 level and the negative symptom sub?scale of PANSS (r=-0.397, P=0.004), CPT score (r=0.378, P=0.006), SCWT-word number (r=0.289, P=0.040), SC? WT-color number (r=0.327, P=0.019) and SCWT-word/color number (r=0.386, P=0.005) in schizophrenic patients. Con?clusion The serum IGF-2 levels of patients with schizophrenia are significantly lower than that of healthy controls, and the IGF-2 level is associated with the severity of negative symptoms and cognitive impairments in patients, indicating that serum IGF-2 might be an indicator of the severity of schizophrenia.

Metastatic pheochromocytoma and paraganglioma(MPPGL)is a rare neuroendocrine tumour in which genetic factors play an important role.In recent years,with the continuous progress of genetic testing technol-ogy,more and more susceptibility genes have been proved to be associated with MPPGL,making early identifica-tion of MPPGL possible.Recent studies have shown that genes associated with the development of MPPGL include SDHA,SDHB,SDHC,SDHD,SDHAF2,FH,MDH2,VHL,IDH1,PDH1/2,SLC25A11,GOT2,DLST,CSDE1,MAML3,H3F3A,MERTK,PCDHGC3,and KIF1B,with SDHA,SDHB,SDHC,SDHD,and SDHAF2 being the common pathogenic genes.Potential mutations affect the clinical manifestations of MPPGL,such as malignant potential and genetic prediction,which can help to better understand the clinical course and treat accordingly.Genetic testing for pheochromocytomas and paragangliomas allows for early detection of genetic syndromes and facilitates close follow-up of high-risk patients.This article provides a review of the progress of research on susceptibility genes identified in MPPGL in recent years,with a view to providing a certain theoretical basis for further related research.