Novel MIP gene mutation causes autosomal-dominant congenital cataract

●AIM:To identify disease-causative mutations in families with congenital cataract.●METHODS:Two Chinese families with autosomaldominant congenital cataract(ADCC)were recruited and underwent comprehensive eye examinations.Gene panel next-generation sequencing of common pathogenic genes of congenital cataract was performed in the proband of each family.Sanger sequencing was used to valid the candidate gene mutations and sequence the other family members for co-segregation analysis.The effect of sequence changes on protein structure and function was predicted through bioinformatics analysis.Major intrinsic protein(MIP)-wildtype and MIP-G29R plasmids were constructed and microinjected into zebrafish single-cell stage embryos.Zebrafish embryonic lens phenotypes were screened using confocal microscopy.●RESULTS:A novel heterozygous mutation(c.85G>A;p.G29R)in the MIP gene was identified in the proband of one family.A known heterozygous mutation(c.97C>T;p.R33C;rs864309693)in MIP was found in the proband of another family.In-silico prediction indicated that the novel mutation might affect the MIP protein function.Zebrafish embryonic lens was uniformly transparent in both wild-type PCS2+MIP and mutant PCS2+MIP.●CONCLUSION:Two missense mutations in the MIP gene in Chinese cataract families are identified,and one of which is novel.These findings expand the genetic spectrum of MIP mutations associated with cataracts.The functional studies suggest that the novel MIP mutation might not be a gain-of-function but a loss-of-function mutation.

Frequency of presenting visual acuity and visual impairment in Chinese college students

AIM:To obtain the baseline data on presenting visual acuity(PVA)and evaluate the prevalence and associated factors for visual impairment based on PVA in 9070 Chinese college students.METHODS:The freshmen at a university in southern China,including 6527 undergraduate students and 2543 graduate students,were investigated for some sociodemographic characteristics and underwent routine medical examination,including measuring PVA,height,and weight.Visual impairment was defined according to the new World Health Organization criteria for blindness and visual impairment.RESULTS:In 9070 college students,the mean PVA in the better eye was 0.094±0.163 log MAR.The prevalence of visual impairment based on PVA was 2.7%.Only 38.3%college students had normal visual acuity[PVA equal to 0 log MAR(20/20)in both eyes].There were 69.8%of students wearing spectacles.Logistic regression showed that home region(non-Guangdong provinces,P<0.0001,OR=1.70)was risk factor for visual impairment while BMI(P=0.001,OR=0.92)was protective factor from visual impairment.Ethnicity(Han Chinese,P<0.0001,OR=3.17)was risk factor for wearing spectacles while age(P=0.01,OR=0.90)was protective factor from wearing spectacles.CONCLUSION:This study provides the baseline data on PVA and the prevalence of visual impairment in Chinese college students.Our analyses reveal that BMI and home region are associated factors for visual impairment based on PVA,while age and ethnicity are associated factors for wearing spectacles.