Expression of the Mf1 gene in developing mouse hearts: implication in the development of human congenital heart defects.

The transcription factor FKHL7 gene has recently been associated with the anterior segment dysgenesis disorder of the eye known as Axenfeld-Rieger anomaly (ARA). A growing body of evidence indicates that mutations in FKHL7 cause not only defects in the anterior segment of the eye but defects in the heart valves and septa as well. In order to evaluate its contribution to normal heart septation and valve formation, expression of the mouse homologue Mf1 in embryonic hearts was analyzed by in situ hybridization. A weak but significant level of Mf1 expression could be detected in the endocardium of mouse embryos as early as day 8.5 post-conception (p.c.). Mf1 expression was undetectable in the hearts of day 9.5 p.c. embryos, but by day 10.5-11 p.c., Mf1 transcripts could be found again in the endocardium of both the atrium and ventricle and a relatively strong signal was observed in the dorsal portion of the septum primum, in what appeared to be the spinal vestibule. At day 13 p.c. when aortic and pulmonary trunks are separated, relatively more Mf1 transcripts were detected in the leaflets of aortic, pulmonary, and venous valves, the ventral portion of the septum primum, as well as in the single layer of cells on the edges of the atrioventricular cushion tissues. Surprisingly, there was no signal detected in the developing interventricular septum. At day 15 p.c., overall Mf1 signals were greatly decreased. However, significant levels of expression could still be observed in the atrial septum, the tricuspid valve, the mitral valve, and in the venous valve but not in the interventricular septum. The temporal and spatial expression patterns of the Mf1 gene in developing mouse hearts suggest that Mf1 may play a critical role in the formation of valves and septa with the exception of the interventricular septum. This is further supported by our studies showing that mutations in the FKHL7 gene were associated with defects in the anterior segment of the eye as well as atrial septal defects or mitral valve defects. Dev Dyn 1999;216:16-27.

Autosomal dominant iris hypoplasia is caused by a mutation in the Rieger syndrome (RIEG/PITX2) gene.

PURPOSE: To determine whether autosomal dominant iris hypoplasia is caused by mutations in the newly described gene for Rieger syndrome (RIEG/PITX2). METHOD: Mutation screening and sequence analysis was performed in a single family. RESULTS: A novel mutation in the RIEG/PITX2 gene was found in all affected but no unaffected individuals. This mutation would be expected to result in an arginine to tryptophan amino acid change in the homeodomain of solurshin, the RIEG/ITX2 gene product. CONCLUSION: Autosomal dominant iris hypoplasia is caused by a defect in the same gene that is defective in many cases of Rieger syndrome.

Identification of a gene that causes primary open angle glaucoma.

Glaucoma is a major cause of blindness and is characterized by progressive degeneration of the optic nerve and is usually associated with elevated intraocular pressure. Analyses of sequence tagged site (STS) content and haplotype sharing between families affected with chromosome 1q-linked open angle glaucoma (GLC1A) were used to prioritize candidate genes for mutation screening. A gene encoding a trabecular meshwork protein (TIGR) mapped to the narrowest disease interval by STS content and radiation hybrid mapping. Thirteen glaucoma patients were found to have one of three mutations in this gene (3.9 percent of the population studied). One of these mutations was also found in a control individual (0.2 percent). Identification of these mutations will aid in early diagnosis, which is essential for optimal application of existing therapies.

Retinal complications after aqueous shunt surgical procedures for glaucoma.

OBJECTIVES: To assess retinal complications and to identify risk factors for retinal complications following aqueous shunt procedures. MATERIALS AND METHODS: Records of 38 consecutive aqueous shunt procedures that were performed on 36 patients at the Eye Institute of the Medical College of Wisconsin, Milwaukee, from June 1993 to March 1995 (minimum follow-up, 6 months) were reviewed. The mean +/- SD follow-up was 11.4 +/- 5.2 months (median, 10.5 months). RESULTS: Twelve patients (32%) had the following retinal complications: 4 serous choroidal effusions (10%) that required drainage, 3 suprachoroidal hemorrhages (8%), 2 vitreous hemorrhages (5%), 1 rhegmatogenous retinal detachment (3%), 1 endophthalmitis (3%), and 1 scleral buckling extrusion (3%). Surgical procedures for retinal complications were required in 8 (67%) of these 12 patients. Visual acuity decreased 2 lines or more in 9 (75%) of these 12 patients. The median onset of a postoperative retinal complication was 12.5 days, with 10 patients (83%) experiencing complications within 35 days. Serous choroidal effusions developed in 10 other patients (26%), and these effusions resolved spontaneously. Visual acuity decreased 2 lines or more in 2 (20%) of these additional 10 patients. Patients who experienced serious retinal complications were significantly older, had a higher rate of hypertension, and postoperative ocular hypotony. Serious retinal complications were distributed evenly among patients with Krupin valves with discs and Molteno and Baerveldt devices. Experience with the Ahmed glaucoma valve implant was limited. CONCLUSION: Aqueous shunt procedures may be associated with significant retinal complications and subsequent visual loss.

Correlation of intraocular pressures in pairs of monozygotic and dizygotic twins.

PURPOSE: Studies of twins may help to establish the importance of hereditary and environmental determinants of chronic diseases. Intraocular pressure (IOP) is a risk factor for glaucoma. The authors hypothesized that IOPs would be more highly correlated between monozygotic (MZ) than between dizygotic (DZ) twins. METHODS: This was a concurrent, case-control study. Volunteer pairs of twins were recruited at a twins' festival. Zygosity was determined by a questionnaire that correlates well with blood-typing classification. Intraocular pressure was measured with a Tonopen six times within 5 minutes (3 times per eye) and averaged. RESULTS: Mean IOP was 14.4 +/- 2.7 mmHg for 61 pairs of MZ twins and 13.9 +/- 2.6 mmHg for 32 pairs of DZ twins. The difference in IOP between the members of a pair was abbreviated delta IOP. The authors found a significant difference in median delta IOP between the MZ and DZ groups (1.2 versus 2.3 mmHg; P = 0.0014). Intraocular pressures were more highly correlated when considering right versus left eyes (intraclass correlation, r1 = 0.853; P < 0.001) than when considering the members of pairs of MZ twins (r1 = 0.735; P < 0.001), which in turn were more highly correlated than pressures of the members of pairs of DZ twins (r1 = 0.407; P = 0.006). CONCLUSIONS: The intraclass correlation for IOP was greater for MZ than for DZ twins. In addition, the median intrapair difference (median delta IOP) was less for MZ than for DZ twins. These results suggest that hereditary factors may play some role in the determination of IOP.

Linkage of autosomal dominant iris hypoplasia to the region of the Rieger syndrome locus (4q25).

Iris hypoplasia is an autosomal dominant disorder which is frequently associated with glaucoma. This glaucoma is usually resistant to medical therapy and can lead to blindness. A large family of Scandinavian descent with a five generation history of iris hypoplasia was studied. Fifteen individuals were found to have iris hypoplasia, nine of whom had associated glaucoma. In an attempt to identify the chromosomal location of the disease-causing gene, this family was genotyped with short tandem repeat polymorphisms (STRPs) known to map to loci previously associated with glaucoma. The juvenile glaucoma locus at 1q25 and a congenital glaucoma locus on 6p were both statistically excluded. However, significant linkage was demonstrated at the Rieger syndrome locus at 4q25. The highest observed LOD score was 3.70 (theta = 0) and was obtained with marker D4S1616. Three recombination events were observed in affected individuals that together demonstrate that the disease-causing gene lies between markers ACT3E03 and D4S1611, an interval of approximately 7 cM. These results suggest that autosomal dominant iris hypoplasia and Rieger syndrome are allelic.

Association between skin color and intraocular pressure in African Americans.

African Americans have a higher prevalence of elevated blood pressure and a higher prevalence of increased intraocular pressure (IOP). The blood pressure of African Americans has been found to be related to skin color. This study evaluated whether IOP was related to skin color. We measured IOP using a Tonopen and skin darkness using a spectrocolorimeter in 213 African Americans. Seventy patients were identified as systemic hypertensives. Spearman correlation coefficients were calculated to compare IOP and skin darkness. Mean IOP among hypertensives was 17.7 +/- 3.6 mmHg and among normotensives was 17.7 +/- 3.8 mmHg. Mean IOP for the whole sample was 17.7 +/- 3.7 mmHg. No significant correlations were found between skin darkness and IOP among the normotensive and hypertensive groups (p = 0.52 and 0.44) nor for the sample as a whole (p = 0.33). Skin darkness as a measure of skin color in this sample population did not predict those subjects with higher IOPs.

Prospective ultrasonographic evaluation of intraoperative and delayed postoperative suprachoroidal hemorrhage from glaucoma filtering surgery.

PURPOSE: To determine the incidence of, visual loss from, and perioperative risk factors for suprachoroidal hemorrhage (SCH) occurring during or after glaucoma filtering surgery. METHODS: Contact B-Scan ultrasonography was used to evaluate at a median of 15 days postoperatively, one eye of 158 patients who underwent various glaucoma filtering procedures during an 18 month period. RESULTS: Ultrasonography detected SCH in 13 patients (8.2%). SCH was recognized during surgery in two cases; 11 were detected postoperatively. Preexisting aphakia (odds ratio 12.9, 95% confidence interval 3.6 to 46.2) and intraoperative anterior vitrectomy (odds ratio 5.2, 95% confidence interval 1.2 to 22.4) were significantly associated with SCH. A significant negative association was found for combined cataract/glaucoma procedures with posterior chamber intraocular lens implantation (odds ratio 0.08, 95% confidence interval 0.01 to 0.69). No significant association between SCH and age, sex, race, diabetes, obesity, systemic hypertension, right versus left eye, type of glaucoma, surgeon, number of preoperative antiglaucoma medications, 5-fluorouracil/mitomycin-C therapy-or previous vitrectomy was found. For some risk factors the power of the study may not be sufficient to establish a correlation: with SCH. Two patients with SCH had serious visual acuity loss and 2 had mild visual acuity loss. Eyes of three patients were surgically drained of SCH. Most patients with SCH did not experience pain, and only one presented-with elevated intraocular pressure at the time SCH was recognized. CONCLUSION: Pre-existing aphakia and concurrent vitrectomy were significant risk factors identified. Combined cataract and glaucoma filtering procedures correlated negatively with suprachoroidal hemorrhage. Most patients with suprachoroidal hemorrhage experienced little or no visual loss, pain, or intraocular pressure elevation.

Ocular implications of long-term prednisone therapy in children.

We compared 23 patients (ages 4 to 18 years) who were receiving long-term oral prednisone therapy with 31 normal controls (ages 7 to 16 years). Indications for corticosteroid treatment included renal transplant in 11 patients, nephrotic syndrome in 7, glomerulonephritis in 4, and vasculitis without renal disease in 1. The mean duration of prednisone therapy was 5.0 +/- 3.5 years, and the mean dose at the time of examination was 0.29 +/- 0.18 mg/kg/day. Mean intraocular pressure was 16.0 +/- 3.0 mm Hg (range, 12 to 25 mm Hg) in the prednisone group and 15.4 +/- 2.1 mm Hg (range, 12 to 20 mm Hg) in the control group. The difference between the means was 0.6 mm Hg (P = 0.35). Posterior subcapsular cataracts were present in seven (30%) of the prednisone patients, but in none of the controls (P = .001). None of the cataracts were visually significant. We found no evidence that pediatric patients on long-term, low-dose prednisone have higher intraocular pressures (IOPs) than normal children, although they are more likely to develop posterior subcapsular cataracts.

Bacterial endophthalmitis following cataract surgery in an eye with a preexisting Molteno implant.

We describe a patient with a preexisting, functioning Molteno implant in whom acute endophthalmitis developed following cataract extraction. The condition was treated successfully without removing the implant.

Compression of the intracranial optic nerve mimicking unilateral normal-pressure glaucoma.

A 66-year-old man developed progressive visual field loss in the inferior arcuate region of the right eye with normal central visual acuity. Intraocular pressures were normal on all but one occasion. The right optic disk showed extensive glaucomalike cupping; the left optic disk was normal. Magnetic resonance imaging revealed a tumor of the right medial sphenoid wing impinging upon the intracranial portion of the right optic nerve. It was resected via a frontotemporal craniotomy. Histopathologic examination revealed a meningothelial meningioma. The visual field and optic disk cupping remained unchanged postoperatively. To our knowledge, this is the first report in which both glaucomalike cupping and visual field loss occurred as the result of a compressive lesion of the anterior visual pathway.

Nonarteritic anterior ischemic optic neuropathy and intraocular pressure.

Several reports have suggested that nonarteritic anterior ischemic optic neuropathy (AION) may be related to increased intraocular pressure. We reviewed the records of 45 patients aged 48 through 86 years with nonarteritic AION (10 patients had bilateral AION) for intraocular pressure measurements and the diagnosis of glaucoma or suspected glaucoma. This group was compared with 45 age- and sex-matched patients with normal eye examination results. The mean +/- SD intraocular pressures were 16.3 +/- 3.3 mm Hg for 45 eyes of the 45 patients with AION and 16.1 +/- 2.8 mm Hg for 45 eyes of the 45 control patients (paired t test, P = .70). Among patients with unilateral AION, intraocular pressure was not greater in the involved eye than in the uninvolved eye. Three patients with AION had a previous diagnosis of glaucoma, while three of the control patients were being followed up with suspected glaucoma. We found no evidence in our series to support the hypothesis that AION is associated with increased intraocular pressure.