A novel missense mutation in the gene encoding major intrinsic protein (MIP) in a Giant panda with unilateral cataract formation

Background Cataracts are defects of the lens that cause progressive visual impairment and ultimately blindness in many vertebrate species. Most cataracts are age-related, but up to one third have an underlying genetic cause. Cataracts are common in captive zoo animals, but it is often unclear whether these are congenital or acquired (age-related) lesions. Results Here we used a functional candidate gene screening approach to identify mutations associated with cataracts in a captive giant panda (Ailuropoda melanoleuca). We screened 11 genes often associated with human cataracts and identified a novel missense mutation (c.686G > A) in the MIP gene encoding major intrinsic protein. This is expressed in the lens and normally accumulates in the plasma membrane of lens fiber cells, where it plays an important role in fluid transport and cell adhesion. The mutation causes the replacement of serine with asparagine (p.S229N) in the C-terminal tail of the protein, and modeling predicts that the mutation induces conformational changes that may interfere with lens permeability and cell–cell interactions. Conclusion The c.686G > A mutation was found in a captive giant panda with a unilateral cataract but not in 18 controls from diverse regions in China, suggesting it is most likely a genuine disease-associated mutation rather than a single-nucleotide polymorphism. The mutation could therefore serve as a new genetic marker to predict the risk of congenital cataracts in captive giant pandas.

Optical Biometry and Influence of Media Opacity Due to Cataract on Development of Axial Length in Pediatric Eyes

Aim: To study the influence of media opacity due to cataract on the development of axial length in paediatric eyes with the help of optical biometry.Method: In this prospective, observational study, all patients attending the paediatric outpatient department (OPD) of the institute underwent a comprehensive ocular and systemic evaluation. Patients suffering from any other ocular disease and systemic disease were excluded. Optical biometry was performed to measure the axial length in all the eyes. In each eye, five biometric measurements were acquired and average of these five readings were considered for the study. Patients were divided into three groups after proper age matching – 1. Group A (Bilateral cataract) 2. Group B (Unilateral cataract) 3. Group C (Bilateral normal). The axial length of the various groups were then compared. Results: A total of 540 eyes of 270 patients were involved in the study. 120 cases (n = 240 eyes) in Group A (bilateral cataract), 30 cases (n = 60 eyes) in Group B (unilateral cataract) and 120 (n = 240 eyes) in Group C (no cataracts). The mean age of the patients in all the groups was 9.38 ± 3.67 years (range: 1-17 years). In Group B, the difference in the AL between the cataractous eyes (22.44±1.48 mm; n = 30) and the fellow eyes (22.09±0.93 mm; n = 30) was not statistically significant (P = 0.277). The difference in the AL between the cataractous right eyes of Group A (22.9±3.51 mm, n = 120) and the non-cataractous right eye of Group C fellow eyes (22.57±0.71 mm, n = 120) was not statistically significant (P = 0.316). The difference in the AL between the cataractous left eyes of Group A (23.06±2.33 mm, n = 120) and the non-cataractous left eyes of Group C fellow eyes (22.56±0.78, n = 120) was statistically significant (P = 0.028). Conclusion: The results of our study and reported literature to date, seem to indicate a more significant role of genetic factors in comparison to media opacity, in the proportionate development of the AL.

A Novel Missense Mutation in the Gene Encoding Major Intrinsic Protein (MIP) in a Giant Panda with Unilateral Cataract Formation

Background: Cataracts are defects of the lens that cause progressive visual impairment and ultimately blindness in many vertebrate species. Most cataracts are age-related, but up to one third have an underlying genetic cause. Cataracts are common in captive zoo animals, but it is often unclear whether these are congenital or acquired (age-related) lesions. Results: Here we used a functional candidate gene screening approach to identify mutations associated with cataracts in a captive giant panda (Ailuropoda melanoleuca). We screened 11 genes often associated with human cataracts and identified a novel missense mutation (c.686G>A) in the MIP gene encoding major intrinsic protein. This is expressed in the lens and normally accumulates in the plasma membrane of lens fiber cells, where it plays an important role in fluid transport and cell adhesion. The mutation causes the replacement of serine with asparagine (p.S229N) in the C-terminal tail of the protein, and modeling predicts that the mutation induces conformational changes that may interfere with lens permeability and cell–cell interactions.Conclusion: The c.686G>A mutation was found in a captive giant panda with a unilateral cataract but not in 18 controls from diverse regions in China, suggesting it is most likely a genuine disease-associated mutation rather than a single-nucleotide polymorphism. The mutation could therefore serve as a new genetic marker to predict the risk of congenital cataracts in captive giant pandas.

Bilateral diffuse anterior scleritis after unilateral cataract surgery: a case report

Surgically induced scleritis (SIS) is a rare complication after a variety of ocular surgeries. Majority of the patients had had two or more surgical procedures before the onset of SIS. We report a patient who developed bilateral diffuse scleritis after unilateral cataract surgery. A 64-year-old man presented with red eye and tenderness in the right eye. An uneventful cataract surgery had been conducted in the right eye 5 months earlier. He had lost vision in the left eye 25 years ago, and there had been no ocular symptoms in both the eyes for the previous 20 years. Scleritis of the right eye appeared 5 months after cataract surgery, and scleritis of the left eye developed three months later. No previous reports referred to the possibility that the right eye surgery could induce scleritis in the left eye. Continuous...

Predicting future axial length in patients with paediatric cataract and primary intraocular lens implantation

Objective: Creating a model to predict Axial Length (AL) growth in paediatric cataract and evaluating influence factors. Material and methods: Eyes with AL measured at surgery and at least one measurement after a 6-month period, from children with unilateral or bilateral cataract and primary IOL implantation, were evaluated. A “rate of axial length growth” (RALG) was calculated for every single eye using these AL measurements and log10 age. One average RALG was calculated for All Eyes and for the groups of Bilateral and Unilateral, Gender, Age at the Surgery, different Visual Acuity, Bilateral Excluded and Not-excluded eye, and Affected and Not-affected eye in unilateral, for comparisons. Results: Average age at surgery from 76 children was 2.83 ± 2.74 (0.11–12.21) years with follow up of 2.84 ± 1.84 (0.52–8.17) years, 29 (37.66%) had unilateral cataract. A total of 357 AL measurements were used, average of 4.70 ± 2.13 (2–10) measurements per eye. The average RALG for all eyes was 4.51 ± 3.06. There were no RALG significant differences comparing Unilateral and Bilateral eyes ( p = 0.51), Male and Female ( p = 0.26), Age at Surgery <0.5 and >0.5 years old ( p = 0.21), both eyes in Bilateral cases ( p = 0.70) and Unilateral Affected and Not-affected eyes ( p = 0.18). The equation Al = initial AL + slope × Log10 ((age + 0.6)⁄(initial age + 0.6)) estimates ALs in different ages. Conclusions: A model to predict AL growth in paediatric cataract was developed. Different studied factors did not significantly influence AL growth.

Bilateral morphometric analysis of corneal sub-basal nerve plexus in patients undergoing unilateral cataract surgery: a preliminary in vivo confocal microscopy study

AimsTo evaluate bilateral morphometric changes of corneal sub-basal nerve plexus (CSNP) occurring after unilateral cataract surgery by in vivo confocal microscopy (IVCM) images analysed with automated software.MethodsIVCM was performed before (V0) and 1 month after surgery (V1) in both operated eyes (OEs) and unoperated eyes (UEs) of 30 patients. Thirty age and sex-matched subjects acted as controls. Corneal nerve fibre density (CNFD), corneal nerve branch density (CNBD), corneal nerve fibre length (CNFL), corneal nerve total branch density (CTBD), corneal nerve fibre area (CNFA), corneal nerve fibre width, corneal nerve fractal dimension (CNFrD) and dendritic cells density were calculated.ResultsMean CNFD, CNBD, CNFL, CTBD, CNFA and CNFrD significantly decreased at V1 versus V0 in both eyes (respectively, 15.35±7.00 vs 21.21±6.56 n/mm2 in OEs and 20.11±6.69 vs 23.20±7.26 in UEs; 13.57±12.16 vs 26.79±16.91 n/mm2 in OEs and 24.28±14.88 vs 29.76±15.25 in UEs; 9.67±3.44 mm/mm2 vs 13.49±3.42 in OEs and 12.53±3.60 vs 14.02±3.82 in UEs; 22.81±18.77 vs 42.25±24.64 n/mm2 in OEs and 38.06±20.52 vs 43.93±22.27 in UEs; 0.0040±0.0021 vs 0.0058±0.0020 mm2/mm2 in OEs and 0.0049±0.0016 vs 0.0057±0.0019 in UEs; 1.418±0.058 vs 1.470±0.037 in OEs and 1.466±0.040 vs 1.477±0.036 in UEs; always p<0.049).ConclusionPatients undergoing cataract surgery exhibit bilateral alterations of CSNP. This finding could have broad implications in the setting of sequential cataract surgery.