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Purpose Dysregulation of the alternative complement pathway is a major pathogenic mechanism in age-related macular degeneration. We investigated whether locally synthesized complement components contribute to AMD by profiling complement expression in postmortem eyes with and without AMD. Methods AMD severity grade 1 to 4 was determined by analysis of postmortem acquired fundus images and hematoxylin and eosin stained histological sections. TaqMan (donor eyes n = 39) and RNAscope/in situ hybridization (n = 10) were performed to detect complement mRNA. Meso scale discovery assay and Western blot (n = 31) were used to measure complement protein levels. Results The levels of complement mRNA and protein expression were approximately 15- to 100-fold (P < 0.0001-0.001) higher in macular retinal pigment epithelium (RPE)/choroid tissue than in neural retina, regardless of AMD grade status. Complement mRNA and protein levels were modestly elevated in vitreous and the macular neural retina in eyes with geographic atrophy (GA), but not in eyes with early or intermediate AMD, compared to normal eyes. Alternative and classical pathway complement mRNAs (C3, CFB, CFH, CFI, C1QA) identified by RNAscope were conspicuous in areas of atrophy; in those areas C3 mRNA was observed in a subset of IBA1+ microglia or macrophages. Conclusions We verified that RPE/choroid contains most ocular complement; thus RPE/choroid rather than the neural retina or vitreous is likely to be the key site for complement inhibition to treat GA or earlier stage of the disease. Outer retinal local production of complement mRNAs along with evidence of increased complement activation is a feature of GA.

Purpose To find immunohistochemical markers that distinguish adenocarcinoma of the nonpigmented ciliary epithelium (NPCE) from metastatic carcinoma, especially metastatic renal cell carcinoma. Design Retrospective case series. Methods Three cases of adenocarcinoma of the NPCE were examined histologically with hematoxylin-eosin stain and immunohistochemical stains including vimentin, AE1/AE3, Cam 5.2, CK7, PAX2, PAX8, AMACR, and CAIX. We also reviewed previously reported cases of this tumor. Results We found that the immunohistochemical profile of adenocarcinoma of the NPCE can overlap with renal cell carcinoma. Both tumors can express vimentin, cytokeratin AE1/AE3, Cam 5.2, PAX2, PAX8, and AMACR. One of the adenocarcinomas of the NPCE in our series also expressed CD10 and the renal cell carcinoma marker (RCC Ma). Carbonic anhydrase IX (CAIX) was not detected in any of the 3 tumors. Conclusions Adenocarcinomas arising in phthisic eyes can be diagnostically challenging. We have found it particularly difficult to distinguish adenocarcinoma of the NPCE from metastatic carcinoma, especially metastatic clear cell renal cell carcinoma and papillary renal cell carcinoma. Because of the immunophenotypic overlap, most patients will require systemic workup including imaging of the kidneys to be certain of the diagnosis.

Purpose To identify associations between systemic medications and primary open-angle glaucoma (POAG) requiring a procedure using United States insurance claims data in a hypothesis-generating study. Design Database study. Participants In total, 6130 POAG cases (defined as patients with POAG undergoing a glaucoma procedure) were matched to 30 650 controls (defined as patients undergoing cataract surgery but without a coded glaucoma diagnosis, procedure, or medication) by age, gender, and region of residence. Methods Participant prescription drug use was calculated for the 5-year period before the glaucoma procedure or cataract surgery. Separately for individual generic drugs and drug classes, logistic regression was used to assess the association with POAG status. This was done across all generic drugs and drug classes that were prescribed in at least 1% of cases and controls. Analyses were adjusted for age, sex, region of residence, employment status, insurance plan type, and the total number of drugs prescribed. Main Outcome Measures Odds ratio (OR) and 95% confidence intervals (CIs) for the association between each drug or drug class and POAG. Results The median age of participants was 72 years, and 52% were women. We tested for associations of POAG with 423 drug classes and 1763 generic drugs, resulting in a total of 2186 statistical tests and a Bonferroni-adjusted significance threshold of P −5 . Selective serotonin reuptake inhibitors (SSRIs) were strongly associated with a reduced risk of POAG (OR, 0.70; 95% CI, 0.64–0.76; P = 1.0 × 10 −15 ); the most significant drug in this class was citalopram (OR, 0.66; 95% CI, 0.57–0.77; P = 1.2 × 10 −7 ). Calcium channel blockers were strongly associated with an increased risk of POAG (OR, 1.26; 95% CI, 1.18–1.35; P = 1.8 × 10 −11 ); the most significant drug in this class was amlodipine (OR, 1.27; 95% CI, 1.18–1.37; P = 5.9 × 10 −10 ). Conclusions We present data documenting potential associations of SSRIs and calcium channel blockers with POAG requiring a procedure. Further research may be indicated to better evaluate any associates of serotonin metabolism or calcium channels in glaucoma, or establish whether the associations are due to variations in the patterns for prescribing these drugs.

Protein drugs that neutralize vascular endothelial growth factor (VEGF), such as aflibercept or ranibizumab, rescue vision in patients with retinal vascular diseases. Nonetheless, optimal visual outcomes require intraocular injections as frequently as every month. Here we report a method to extend the intravitreal half-life of protein drugs as an alternative to either encapsulation or chemical modifications with polymers. We combine a 97-amino-acid peptide of human origin that binds hyaluronan, a major macromolecular component of the eye's vitreous, with therapeutic antibodies and proteins. When administered to rabbit and monkey eyes, the half-life of the modified proteins is increased ∼3–4-fold relative to unmodified proteins. We further show that prototype long-acting anti-VEGF drugs (LAVAs) that include this peptide attenuate VEGF-induced retinal changes in animal models of neovascular retinal disease ∼3–4-fold longer than unmodified drugs. This approach has the potential to reduce the dosing frequency associated with retinal disease treatments., Retinal vascular disease treatments involve frequent pharmacological intraocular administrations. Here the authors present a method to increase the half-life of injected drugs by fusing these to a hyaluronan-binding peptide, which might lead to less frequent retinal disease treatments.

A 53-year-old man presented with smooth-domed, variegated cysts (polycystic disease) of all 4 eyelids, worse on the left side. Some of the cysts were clear, while others were creamy-white colored. In addition, multiple, very fine vesicopapules were noted along the eyelid margins. Histopathologic examination revealed a trichilemmal cyst, several pure apocrine hidrocystomas displaying multiple chambers, a hybrid cyst, and many small eccrine cysts of the deep dermis. The apocrine lesions, including the small ones at the eyelid margins, predominated. Smooth muscle actin sometimes positively stained outer myoepithelial cells in some of the apocrine cysts, which helped to distinguish them from eccrine cysts. Most noteworthy was the fact that the patient had been diagnosed with a prolactinoma 20 years earlier. There is only 1 previous report of multiple apocrine cysts and an antecedent prolactinoma in the dermatologic literature. This syndrome should be separated from that of Schöpf-Schulz-Passarge, which manifests multiple small eyelid apocrine cysts and other ectodermal dysplasias without any association with neoplasia, and from that of focal dermal hypoplasia (Goltz-Gorlin) syndrome with apocrine cysts but again without neoplasia.

We sought to refine understanding about associations identified in prior studies between angiotensin-II receptor blockers, metformin, selective serotonin reuptake inhibitors, fibric-acid derivatives, or calcium channel blockers and progression to glaucoma filtration surgery for open-angle glaucoma (OAG). We used new-initiator, active-comparator cohort designs to investigate these drugs in two data sources. We adjusted for confounders using stabilized inverse-probability-of-treatment weights and evaluated results using "intention-to-treat" and "as-treated" follow-up approaches. In both data sources, Kaplan-Meier curves showed trends for more rapid progression to glaucoma filtration surgery in patients taking calcium channel blockers compared with thiazides with as-treated (MarketScan P = 0.15; Medicare P = 0.03) and intention-to-treat follow-up (MarketScan P < 0.01; Medicare P = 0.10). There was suggestion of delayed progression for selective serotonin reuptake inhibitor compared with tricyclic antidepressants in Medicare, which was not observed in MarketScan. Our study provided support for a relationship between calcium channel blockers and OAG progression but not for other investigated drugs.

Objective: To evaluate whether inhibition of the pro-inflammatory cytokines IL-1β or IL-17A by canakinumab or secukinumab, respectively, influence the signs and symptoms of dry eye. Design: A double-masked, placebo-controlled, outpatient clinical trial. Participants: Seventy-two patients with moderate to severe dry eye. Methods: Patients were randomized in a 1:1:1 ratio to the following three treatments: a single intravenous dose of canakinumab that neutralizes IL-1β, a single intravenous dose of secukinumab that neutralizes IL-17A, or an intravenous dose of placebo. The signs and symptoms of dry eye were evaluated on the treatment day and 1 week, 4 weeks, and 8 weeks after the treatment. Main Outcome Measures: The pre-specified primary efficacy endpoint was corneal staining in the study eye as measured by the NEI staining score 4 weeks after treatment. Secondary endpoints at that visit and 1 week and 8 weeks after treatment included tear production (Schirmer test), tear film breakup time, conjunctival redness, the ocular surface disease index (OSDI), the frequency of a desire for a topical ocular lubricant, and visual acuity. Results: Of the 71 patients included in the analysis of safety, the rate of adverse events was similar between treatment groups; in particular, there was no noteworthy excess of adverse events in the canakinumab and secukinumab groups compared with the placebo group. Sixty-nine patients appropriately completed the study and were included in the analyses of efficacy. The course of corneal staining scores from baseline to four weeks, respectively, were for canakinumab 1.46 to 1.33 (p = 0.62 compared to placebo), for secukinumab 1.46 to 1.23 (p = 0.22), and for placebo 1.68 to 1.42. There were no changes in the other measures of efficacy beyond what was within the range expected for stochastic day-to-day variation. Conclusions: Neither canakinumab nor secukinumab substantially improved the corneal staining score (the primary endpoint) or improved the other measures of the severity of dry eye. The results suggest that the inhibition of IL-1β or IL-17A obtained by systemic administration of neutralizing drugs does not influence the severity of dry eye.

We report three unrelated patients with mutations in the GRM6 gene that normally encodes the glutamate receptor mGluR6. This neurotransmitter receptor has been shown previously to be present only in the synapses of the ON bipolar cell dendrites, and it mediates synaptic transmission from rod and cone photoreceptors to this type of second-order neuron. Despite the synaptic defect, best visual acuities were normal or only moderately reduced (20/15 to 20/40). The patients were night blind from an early age, and when maximally dark-adapted, they could perceive lights only with an intensity equal to or slightly dimmer than that normally detected by the cone system (i.e., 2-3 log units above normal). Electroretinograms (ERGs) in response to single brief flashes of light had clearly detectable a-waves, which are derived from photoreceptors, and greatly reduced b-waves, which are derived from the second-order inner retinal neurons. ERGs in response to sawtooth flickering light indicated a markedly reduced ON response and a nearly normal OFF response. There was no subjective delay in the perception of suddenly appearing white vs. black objects on a gray background. These patients exemplify a previously unrecognized, autosomal recessive form of congenital night blindness associated with a negative ERG waveform.

Unrelated patients with achromatopsia, macular degeneration with onset under age 50 years, cone degeneration or dysfunction, cone-rod degeneration, or macular malfunction were screened for mutations in the three genes known to be associated with achromatopsia: the GNAT2 gene encoding the α subunit of cone transducin and the CNGA3 and CNGB3 genes encoding the α and β subunits of the cone cGMP-gated cation channel. We found no examples of patients with GNAT2 mutations. Out of 36 achromats, 12 (33%) had mutations in CNGA3 (13 different mutations including five novel mutations) and 12 (33%) had mutations in CNGB3 (six different mutations including four novel mutations). All achromats with CNG mutations had residual, presumably cone function as determined by computer-averaged 30-Hz electroretinograms (ERGs). There was considerable variability in acuity and color vision, with most patients having acuities of 20/200–20/400 and complete absence of color perception, and others having acuities of 20/25–20/40 and some color vision. Two pseudodominant achromatopsia cases were uncovered, both with CNGA3 mutations, including one family in which some compound heterozygotes with achromatopsia mutations were clinically unaffected. We found two novel CNGB3 changes in three patients with juvenile macular degeneration, a phenotype not previously associated with mutations in the cone channel subunits. These patients had subnormal acuity (20/30–20/60), normal to subnormal color vision, and normal to subnormal full-field cone ERG amplitudes. Our results indicate that some patients with channel protein mutations retain residual foveal cone function. Based on our findings, CNGB3 should be considered as a candidate gene to be evaluated in patients with forms of cone dysfunction, including macular degeneration. Hum Mutat 25:248–258, 2005. © 2005 Wiley-Liss, Inc.

Mutations in the inosine monophosphate dehydrogenase 1 gene (IMPDH1) have recently been discovered to cause a form of autosomal dominant retinitis pigmentosa (adRP). Such mutations are estimated to account for approximately 2-5% of the adRP cases among Americans of European origin and Europeans. Aiming towards an understanding of the molecular background of retinitis pigmentosa, this paper describes the phenotype of a Swedish family with a mutation in IMPDH1.Venous blood samples were obtained from 12 family members and screened for mutations in IMPDH1. Six individuals with the mutation were examined clinically and with full-field electroretinography (ERG), dark adaptometry, multifocal electroretinography (mfERG), and optical coherence tomography (OCT). Also reviewed were the clinical findings and ERGs obtained 14 years earlier.The proband and eight other relatives from three generations were found to harbor the Asp226Asn mutation in IMPDH1. These individuals, from three generations, showed clinical and electrophysiological signs of retinitis pigmentosa. The cone responses to the full-field, 30-Hz flicker ERG demonstrated an unusual pattern, with implicit times within normal limits or only slightly prolonged. Rod ERG responses, however, were undetectable. OCT showed intraretinal fluid and swelling, changes that were more pronounced in younger individuals. mfERG showed residual preserved central function. The older the individual, the smaller the area of preserved central function.In this family with a mutation in IMPDH1, we found a specific phenotype with rod function affected more than cone function, foveal edema, and central retinal function preserved for a long period of time. Foveal edema could be a pathogenic feature in this form of retinal degeneration.

This paper reviews the published histopathologic findings of patients with retinitis pigmentosa (RP) or an allied disease in whom the responsible gene defect was identified, including 10 cases with dominant RP (cases with mutations in RHO, PRPC8, and RP1), three with dominant spinocerebellar ataxia (SCA7), three X-linked RP carrier females (RPGR), two with congenital retinal blindness (AIPL1 and RPE65), two with mitochondrial encephalomyopathy overlap syndrome (MTTL1), and one case each with dominant cone degeneration (GCAP1), X-linked cone degeneration (RCP), enhanced S-cone syndrome (NR2E3), and dominant late-onset retinal degeneration (CTRP5). No histopathologic descriptions were found of the vast majority of genetically defined forms of retinal degeneration.

Mice lacking the transcription factor Nrl have no rod photoreceptors and an increased number of short-wavelength-sensitive cones. Missense mutations in NRL are associated with autosomal dominant retinitis pigmentosa; however, the phenotype associated with the loss of NRL function in humans has not been reported. We identified two siblings who carried two allelic mutations: a predicted null allele (L75fs) and a missense mutation (L160P) altering a highly conserved residue in the domain involved in DNA-binding-site recognition. In vitro luciferase reporter assays demonstrated that the NRL-L160P mutant had severely reduced transcriptional activity compared with the WT NRL protein, consistent with a severe loss of function. The affected patients had night blindness since early childhood, consistent with a severe reduction in rod function. Color vision was normal, suggesting the presence of all cone color types; nevertheless, a comparison of central visual fields evaluated with white-on-white and blue-on-yellow light stimuli was consistent with a relatively enhanced function of short-wavelength-sensitive cones in the macula. The fundi had signs of retinal degeneration (such as vascular attenuation) and clusters of large, clumped, pigment deposits in the peripheral fundus at the level of the retinal pigment epithelium (clumped pigmentary retinal degeneration). Our report presents an unusual clinical phenotype in humans with loss-of-function mutations in NRL .

A screen of the entire coding region of the USH2A gene in 129 unrelated patients with Usher syndrome type II (USH2) and in 146 unrelated patients with non-syndromic autosomal recessive retinitis pigmentosa (ARRP) uncovered 54 different sequence variations, including 18 likely pathogenic mutations (13 frameshift, three nonsense, and two missense), 12 changes of uncertain pathogenicity (11 missense changes and one in-frame deletion), and 24 non-pathogenic rare variants or polymorphisms. Of the 18 likely pathogenic mutations, nine were novel. Among the USH2 patients, 50 (39%) had one or two likely pathogenic mutations. The most common mutant allele in USH2 patients was E767fs, which was found in 29 patients, including one homozygote. Among the ARRP patients, we found 17 (12%) with one or two likely pathogenic mutations. The most common mutant allele in ARRP patients was C759F and it was found in 10 patients. The C759F allele was also found in two USH2 patients; in neither of them was a change in the other allele found. The second most common mutant allele in both patient groups was L1447fs (found in 6/50 USH2 patients and 6/17 ARRP patients). Of the 50+17=67 patients with identified USH2A mutations, only one mutation in one allele was found in 41+12=53 (79%); the reason for the high proportion of patients with only one identified mutation is obscure. Our results indicate that USH2A mutations are found in about 7% of all cases of RP in North America, a frequency similar to the RPGR gene (8%) and the rhodopsin gene (10%).

PURPOSE To describe the clinical presentation of cutaneous benign mixed tumor of the eyelid and its management options. METHODS Periocular cases of cutaneous benign mixed tumor were gathered from members of an oculoplastics specialty Internet discussion group. A total of 9 patients are described in this retrospective, interventional case series. The clinical presentation, histopathology, and management of these lesions is reviewed. RESULTS Patients were typically asymptomatic, presenting with a slowly enlarging, nontender nodule of 2 to 8 years' duration. The lesions ranged from 4 mm to 17 mm in greatest dimension. Four of the lesions were on the eyelid margin, three in the sub-brow area of the upper eyelid, and two in the central lids. All six cases not involving the brow were fixed to the tarsus; one brow lesion was believed to be adherent to the skin. None of the lesions was associated with significant changes of the overlying epidermis, although one lesion showed overlying pigmentation. All patients underwent excisional biopsy for diagnostic or cosmetic reasons. On histopathologic examination, the tumors were biphasic, with an epithelial component exhibiting apocrine or hair follicle differentiation and a myxoid, adipocytic, chondroid, and/or fibrous stroma. The pathologic diagnoses were all consistent with cutaneous benign mixed tumor (chondroid syringoma, pleomorphic adenoma). Follow-up ranged from 2 weeks to 12 months, although several patients failed to keep scheduled follow-up appointments. No clinical recurrences were identified. CONCLUSIONS Cutaneous benign mixed tumor may occur in the eyelid, and, although uncommon, should be included in the differential diagnosis of firm, nodular eyelid tumors. The histopathologic features are similar to those seen in this tumor type arising in other areas of the body. Preoperative consideration of this diagnostic possibility may allow the surgeon to plan for complete excision, thereby reducing the possibility of recurrence or malignant transformation.

Purpose We attempted to reproduce published studies that evaluated whether the following factors influence choroidal neovascularization (CNV) induced by laser photocoagulation in murine retinas: small interfering RNA (siRNA), cobra venom factor, complement factors C3 and C5, and complement receptor C5aR. In addition, we explored whether laser-induced CNV in mice was influenced by the vendor of origin of the animals. Methods Reagents or genotypes reported by others to influence CNV in this model were assessed using our standard procedures. Retrospective analyses of control or placebo mice in many experiments were done to evaluate whether the CNV area induced by laser photocoagulation varied according to vendor. Results Administration of the following agents did not have a substantial impact on the CNV induced by laser burns in mice: siRNA, low-molecular-weight inhibitor of the C5a receptor (PMX53), or cobra venom factor. Jackson Laboratory (JAX) mice lacking either C3 or C5 had increased neovascularization compared to non-littermate JAX wild-type controls. Taconic mice lacking C3 had reduced CNV compared to non-littermate Taconic wild-type control mice. A retrospective analysis of vehicle-treated wild-type C57BL/6 mice used as controls across 132 experiments conducted from 2007 to 2010 revealed that mice purchased from JAX or from Charles River produced less neovascularization than mice from Taconic. Conclusions We present our recommended methods for conducting experiments with the mouse laser-induced CNV model to enhance reproducibility and minimize investigator bias.

We used the serial analysis of gene expression (SAGE) technique to catalogue and measure the relative levels of expression of the genes expressed in the human peripheral retina, macula, and retinal pigment epithelium (RPE) from one or both of two humans, aged 88 and 44 years. The cone photoreceptor contribution to all transcription in the retina was found to be similar in the macula versus the retinal periphery, whereas the rod contribution was greater in the periphery versus the macula. Genes encoding structural proteins for axons were found to be expressed at higher levels in the macula versus the retinal periphery, probably reflecting the large proportion of ganglion cells in the central retina. In comparison with the younger eye, the peripheral retina of the older eye had a substantially higher proportion of mRNAs from genes encoding proteins involved in iron metabolism or protection against oxidative damage and a substantially lower proportion of mRNAs from genes encoding proteins involved in rod phototransduction. These differences may reflect the difference in age between the two donors or merely interindividual variation. The RPE library had numerous previously unencountered tags, suggesting that this cell type has a large, idiosyncratic repertoire of expressed genes. Comparison of these libraries with 100 reported nonocular SAGE libraries revealed 89 retina-specific or enriched genes expressed at substantial levels, of which 14 are known to cause a retinal disease and 53 are RPE-specific genes. We expect that these libraries will serve as a resource for understanding the relative expression levels of genes in the retina and the RPE and for identifying additional disease genes.

We isolated and characterized the entire coding sequence of a human gene encoding a protein that interacts with RPGR, a protein that is absent or mutant in many cases of X-linked retinitis pigmentosa. The newly identified gene, called “RPGRIP1” for RPGR-interacting protein (MIM 605446), is located within 14q11, and it encodes a protein predicted to contain 1,259 amino acids. Previously published work showed that both proteins, RPGR and RPGRIP1, are present in the ciliary structure that connects the inner and outer segments of rod and cone photoreceptors. We surveyed 57 unrelated patients who had Leber congenital amaurosis for mutations in RPGRIP1 and found recessive mutations involving both RPGRIP1 alleles in 3 (6%) patients. The mutations all create premature termination codons and are likely to be null alleles. Patients with RPGRIP1 mutations have a degeneration of both rod and cone photoreceptors, and, early in life, they experience a severe loss of central acuity, which leads to nystagmus.

Microdeletions Glu767(1-bp del), Thr967(1-bp del), and Leu1446(2-bp del) in the human USH2A gene have been reported to cause Usher syndrome type II, a disorder characterized by retinitis pigmentosa (RP) and mild-to-severe hearing loss. Each of these three frameshift mutations is predicted to lead to an unstable mRNA transcript that, if translated, would result in a truncated protein lacking the carboxy terminus. Here, we report Cys759Phe, a novel missense mutation in this gene that changes an amino-acid residue within the fifth laminin–epidermal growth factor–like domain of the USH2A gene and that is associated with recessive RP without hearing loss. This single mutation was found in 4.5% of 224 patients with recessive RP, suggesting that USH2A could cause more cases of nonsyndromic recessive RP than does any other gene identified to date.

Loss of heterozygosity at tumor-suppressor loci is an important oncogenic mechanism first discovered in retinoblastomas. We explored this phenomenon by examining a set of matched retinoblastoma and leukocyte DNA samples from 158 patients informative for DNA polymorphisms. Loss of heterozygosity at the retinoblastoma locus (13q14) was observed in 101 cases, comprising 7 cases with a somatic deletion causing hemizygosity and 94 with homozygosity (isodisomy). Homozygosity was approximately equally frequent in tumors from male and female patients, among patients with a germ-line vs. somatic initial mutation, and among patients in whom the initial mutation occurred on the maternal vs. paternal allele. A set of 75 tumors exhibiting homozygosity was investigated with markers distributed in the interval 13cen–13q14. Forty-one tumors developed homozygosity at all informative marker loci, suggesting that homozygosity occurred through chromosomal nondisjunction. The remaining cases exhibited mitotic recombination. There was no statistically significant bias in apparent nondisjunction vs. mitotic recombination among male vs. female patients or among patients with germ-line vs. somatic initial mutations. We compared the positions of somatic recombination events in the analyzed interval with a previously reported meiotic recombination map. Although mitotic crossovers occurred throughout the assayed interval, they were more likely to occur proximally than a comparable number of meiotic crossovers. Finally, we observed four triple-crossover cases, suggesting negative interference for mitotic recombination, the opposite of what is usually observed for meiotic recombination.

Retinitis pigmentosa (RP) constitutes a group of genetically heterogeneous progressive photoreceptor degenerations leading to blindness and affecting 50,000-100,000 people in the U.S. alone. Over 20 different RP loci have been mapped, of which six have been identified. Three of these encode members of the rod photoreceptor visual transduction cascade: rhodopsin, the rod cGMP-gated cation channel alpha subunit, and the beta subunit of cGMP-phosphodiesterase (PDEB). As null mutations in PDEB cause some cases of RP and since both alpha and beta subunits are required for full phosphodiesterase activity, we examined the gene encoding the alpha subunit of cGMP phosphodiesterase (PDEA) in 340 unrelated patients with RP. We found three point mutations in PDEA in affected members of two pedigrees with recessive RP. Each mutation alters an essential functional domain of the encoded protein and likely disrupts its catalytic function. PDEA is the seventh RP gene identified, highlighting the extensive genetic heterogeneity of the disorder and encouraging further investigation into the role of other members of the phototransduction cascade in RP.

We present a clinical pathological review of vitreous amyloidosis in a case of familial amyloidotic polyneuropathy, type I. Vitreous opacification was the first manifestation of disease in the proband, who was successfully treated with vitrectomy. The eyes were obtained at autopsy after the patient died from an unrelated cause, and the histopathology is presented here. Analysis of DNA from the pathology specimen revealed the most commonly reported transthyretin mutation, Val30Met. The classification of systemic and ocular amyloidosis as well as the genetics of familial amyloidotic polyneuropathy are briefly reviewed.

Mutations in the genes encoding two proteins of the retinal rod phototransduction cascade, opsin and the beta subunit of rod cGMP phosphodiesterase, cause retinitis pigmentosa (RP) in some families. Here we report defects in a third member of this biochemical pathway in still other patients with this disease. We screened 94 unrelated patients with autosomal dominant RP and 173 unrelated patients with autosomal recessive RP for mutations in the gene encoding the alpha subunit of the rod cGMP-gated cation channel. Five mutant sequences cosegregated with disease among four unrelated families with autosomal recessive RP. Two of these were nonsense mutations early in the reading frame (Glu76End and Lys139End) and one was a deletion encompassing most if not all of the transcriptional unit; these three alleles would not be expected to encode a functional channel. The remaining two mutations were a missense mutation (Ser316Phe) and a frameshift [Arg654(1-bp del)] mutation truncating the last 32 aa in the C terminus. The latter two mutations were expressed in vitro and found to encode proteins that were predominantly retained inside the cell instead of being targeted to the plasma membrane. We conclude that the absence or paucity of functional cGMP-gated cation channels in the plasma membrane is deleterious to rod photoreceptors and is an uncommon cause of RP.

Mutations in the gene encoding the beta subunit of rod cGMP phosphodiesterase are known causes of photoreceptor degeneration in two animal models of retinitis pigmentosa, the rd (retinal degeneration) mouse and the Irish setter dog with rod/cone dysplasia. Here we report a screen of 92 unrelated patients with autosomal recessive retinitis pigmentosa for defects in the human homologue of this gene. We identified seven different mutations that cosegregate with the disease. They were found among four patients with each patient heterozygously carrying two mutations. All of these mutations are predicted to affect the putative catalytic domain, probably leading to a decrease in phosphodiesterase activity and an increase in cGMP levels within rod photoreceptors. Mutations in the gene encoding the beta subunit of rod phosphodiesterase are the most common identified cause of autosomal recessive retinitis pigmentosa, accounting for approximately 4% of cases in North America.

A number of mutations in the rhodopsin gene have been shown to cause both dominant and recessive retinitis pigmentosa. Here we describe another phenotype associated with a defect in this gene. We discovered a patient with congenital stationary night blindness who carries the missense mutation Ala292Glu. When coupled with 11-cis-retinal in vitro, Ala292Glu rhodopsin is able to activate transducin in a light-dependent manner like wild-type rhodopsin. However, without a chromophore, Ala292Glu opsin anomalously activates transducin. We speculate that the rod dysfunction in this patient is due to an abnormal, continuous activation of transducin by mutant opsin molecules in photoreceptor outer segments.

THE murine retinal degeneration slow (rds) gene is a semidominant mutation with a phenotype having rod and cone photoreceptors that develop abnormally and then slowly degenerate1–3. The phenotype is a possible model for retinitis pigmentosa, one of the scores of hereditary human retinal degenerations, which is also characterized by photoreceptor degeneration. We report here three mutations of the human homologue of the rds gene (RDS) that cosegregate with autosomal dominant retinitis pigmentosa in separate families. Our results indicate that some cases of autosomal dominant retinitis pigmentosa are due to mutations at the RDS locus.

We searched for point mutations in every exon of the rhodopsin gene in 150 patients from separate families with autosomal dominant retinitis pigmentosa. Including the 4 mutations we reported previously, we found a total of 17 different mutations that correlate with the disease. Each of these mutations is a single-base substitution corresponding to a single amino acid substitution. Based on current models for the structure of rhodopsin, 3 of the 17 mutant amino acids are normally located on the cytoplasmic side of the protein, 6 in transmembrane domains, and 8 on the intradiscal side. Forty-three of the 150 patients (29%) carry 1 of these mutations, and no patient has more than 1 mutation. In every family with a mutation so far analyzed, the mutation cosegregates with the disease. We found one instance of a mutation in an affected patient that was absent in both unaffected parents (i.e., a new germ-line mutation), indicating that some "isolate" cases of retinitis pigmentosa carry a mutation of the rhodopsin gene.

Purpose Great variation exists in the age of onset of symptoms and the severity of disease at a given age in patients with retinitis pigmentosa (RP). The final pathway for this disease may involve apoptotic photoreceptor cell death. Telomere length is associated with biologic aging, senescence, and apoptosis. We evaluated whether the length of telomeres in leukocytes correlated with the severity of RP in patients with the Pro23His rhodopsin mutation who have shown marked heterogeneity in disease severity. Methods We evaluated 122 patients with the Pro23His rhodopsin mutation. The patients’ retinal function was stratified according to their 30-Hz cone electroretinogram (ERG). The length of telomeres in leukocytes was measured by the quantitative real time polymerase chain reaction (qRT–PCR) method in the 15 patients with the highest age-adjusted 30-Hz ERG amplitudes and in the 15 patients with the lowest amplitudes. Results Mean leukocyte telomere length was similar in the 15 patients with the highest cone ERG amplitudes (median: 0.40 units; interquartile range 0.36–0.56) and the 15 patients with the lowest cone amplitudes (median: 0.41 units; inter quartile range 0.34 −0.64; p=0.95). Conclusions We found no evidence for an association between telomere length and the severity of RP as monitored by the cone ERG in patients with the Pro23His rhodopsin mutation.

Here we describe two families with retinitis pigmentosa, a hereditary neurodegeneration of rod and cone photoreceptors in the retina. Affected family members were homozygous for loss-of-function mutations in IDH3B, encoding the Β-subunit of NAD-specific isocitrate dehydrogenase (NAD-IDH, or IDH3), which is believed to catalyze the oxidation of isocitrate to α-ketoglutarate in the citric acid cycle. Cells from affected individuals had a substantial reduction of NAD-IDH activity, with about a 300-fold increase in the Km for NAD. NADP-specific isocitrate dehydrogenase (NADP-IDH, or IDH2), an enzyme that catalyzes the same reaction, was normal in affected individuals, and they had no health problems associated with the enzyme deficiency except for retinitis pigmentosa. These findings support the hypothesis that mitochondrial NADP-IDH, rather than NAD-IDH, serves as the main catalyst for this reaction in the citric acid cycle outside the retina, and that the retina has a particular requirement for NAD-IDH.

Purpose: To identify mutations in KCNV2 in patients with a form of cone dystrophy characterized by a supernormal rod electroretinogram (ERG). Methods: The 2 exons and flanking intron DNA of KCNV2 from 8 unrelated patients were PCR amplified and sequenced. Results: We found 1 frameshift, 2 nonsense, 1 non-stop, and 6 missense mutations. Every patient had one or two mutations identified. Of the missense mutations, 4 affected residues were in the amino terminal region of the protein, and two in the pore region. Conclusions: KCNV2 mutations account for most if not all cases of cone dystrophy with a supernormal rod ERG.

Objective: To examine if the genes encoding complement factor H (CFH), apolipoprotein E (APOE), and elongation of very-long-chain fatty acids–like 4 (ELOVL4) confer risk of neovascular age-related macular degeneration (AMD) in an independent or interactive manner when controlling for smoking exposure. Methods: We studied 103 unrelated patients with neovascular AMD who each had at least 1 sibling with normal maculae. Smoking histories were obtained. Genotyping was performed by analyzing amplified genomic fragments from CFH, APOE, and ELOVL4 by direct sequencing or by restriction endonuclease digests. Conditional logistic regression analysis was used to build a multifactor model. Results: For CFH, only the CC genotype carried a statistically significant elevation of disease risk (odds ratio, 49.37; 95% confidence interval, 6.20-393.22; P.001). No significant association was observed between neovascular AMD and APOE or ELOVL4. No significant interactions were found between smoking and having theCFH orAPOE genotype nor were significant interactions found between the CFH, ELOVL4, and APOE genotypes. Conclusions: Smoking and having the CFH CC genotype independently increase risk of neovascular AMD. APOE andELOVL4 genotypes do not seem to modify risk. Clinical Relevance: Smoking 10 pack-years or more and having the CFH CC genotype increase one’s risk of neovascular AMD 144-fold compared with smoking less than 10 pack-years and having the CT or TT genotype. Arch Ophthalmol. 2007;125:49-54

A recessive mutation in the tub gene causes obesity, deafness and retinal degeneration in tubby mice1–4. The tub gene is a member of a family of tubby-like genes (TULPs) that encode proteins of unknown function. Members of this family have been identified in plants, vertebrates and invertebrates4. The TULP proteins share a conserved carboxy-terminal region of approximately 200 amino-acid residues5. Here we report the analysis of the human gene TULP1, which is expressed specifically in the retina5. Upon analysing 162 patients with nonsyndromic recessive retinitis pigmentosa (RP) and 374 simplex cases of RP, we found two who were compound heterozygotes for mutations that cosegregated with disease in the respective families. Three of the mutations are missense changes affecting the conserved C-terminal region; the fourth mutation affects a splice donor site upstream of this region. Our data suggest that mutations in TULP1 are a rare cause of recessive RP and indicate that TULP1 has an essential role in the physiology of photoreceptors.

Hereditary degenerations of the human retina are genetically heterogeneous, with well over 100 genes implicated so far. This Seminar focuses on the subset of diseases called retinitis pigmentosa, in which patients typically lose night vision in adolescence, side vision in young adulthood, and central vision in later life because of progressive loss of rod and cone photoreceptor cells. Measures of retinal function, such as the electroretinogram, show that photoreceptor function is diminished generally many years before symptomic night blindness, visual-field scotomas, or decreased visual acuity arise. More than 45 genes for retinitis pigmentosa have been identified. These genes account for only about 60% of all patients; the remainder have defects in as yet unidentified genes. Findings of controlled trials indicate that nutritional interventions, including vitamin A palmitate and omega-3-rich fish, slow progression of disease in many patients. Imminent treatments for retinitis pigmentosa are greatly anticipated, especially for genetically defined subsets of patients, because of newly identified genes, growing knowledge of affected biochemical pathways, and development of animal models.

Purpose: To report a rare case of isolated ocular sarcoidosis in an HIV positive patient. Design: Case report. Methods: A 47-year-old HIV+ Caucasian male was referred for chronic bilateral follicular conjunctivitis. Results: A conjunctival biopsy that was performed on the right eye showed sarcoidosis. General medical evaluation including a spiral thin cut chest CT scan revealed no systemic involvement. The ocular signs and symptoms resolved completely with topical corticosteroid treatment. Conclusions: HIV infection and sarcoidosis rarely coexist, presumably because their immunopathogenesis mechanisms diverge. In the absence of systemic involvement, a definite diagnosis can only be made by biopsy of the ocular tissues.

Purpose To determine the frequency of mutations in IMPDH1 among patients with autosomal dominant retinitis pigmentosa (RP), to characterize the clinical features of patients with the Asp226Asn mutation in this gene, and to compare these features with those found among patients with selected dominant mutations in other RP genes. Methods The coding sequence and the adjacent flanking intron sequences of all 14 coding exons were sequenced in 183 unrelated patients with dominant RP. The clinical findings evaluated included visual acuity, refractive error, visual field area measured with the Goldmann perimeter, final dark-adaptation threshold, full-field electroretinogram (ERG) amplitudes, cataract, and funduscopic bone spicule pigmentation. Results The mutation Asp226Asn was identified in 6 of the 183 unrelated patients with RP. One patient carried the novel, possibly pathogenic, change Lys238Glu. There was approximately a 100-fold variation in ERG amplitudes among patients of similar age with the Asp226Asn mutation. Patients had similar reductions of rod-plus-cone 0.5-Hz ERG amplitude and cone 30-Hz ERG amplitude. For a given amount of remaining visual field, there was a larger ERG amplitude in IMPDH1-carrying patients (average 0.5-Hz ERG/visual field ratio = 9.5 nV/deg(2)) compared with groups of patients with the RP1 mutation Arg677End (2.8 nV/deg(2)), the rhodopsin (RHO) mutation Pro23His (5.1 nV/deg(2)), or the RHO mutation Pro347Leu (1.7 nV/deg(2)). Conclusions IMPDH1 mutations account for approximately 2% of cases of dominant RP in North America. The most frequent mutation, Asp226Asn, appears to cause at least as much loss of rod function as cone function. Patients with this form of RP retain, on average, two to five times more ERG amplitude per unit of remaining visual area than patients with three other forms of dominant RP.

To identify pathogenic mutations in the guanylate cyclase-activating protein 1 (GCAP1) and GCAP2 genes and to characterize the biochemical effect of mutation on guanylate cyclase (GC) stimulation.The GCAP1 and GCAP2 genes were screened by direct sequencing for mutations in 216 patients and 421 patients, respectively, with various hereditary retinal diseases. A mutation in GCAP1 segregating with autosomal dominant cone degeneration was further evaluated biochemically by employing recombinant proteins, immunoblotting, Ca2+-dependent stimulation of GC, fluorescence emission spectra, and limited proteolysis in the absence and presence of Ca2+.A novel GCAP1 mutation, I143NT (substitution of Ile at codon 143 by Asn and Thr), affecting the EF4 Ca2+-binding loop, was identified in a heterozygote father and son with autosomal dominant cone degeneration. Both patients had much greater loss of cone function versus rod function; previous histopathologic evaluation of the father's eyes at autopsy (age 75 years) showed no foveal cones but a few, scattered cones remaining in the peripheral retina. Biochemical analysis showed that the GCAP1-I143NT mutant adopted a conformation susceptible to proteolysis, and the mutant inhibited GC only partially at high Ca2+ concentrations. Individual patients with atypical or recessive retinitis pigmentosa (RP) had additional heterozygous GCAP1-T114I and GCAP2 gene changes (V85M and F150C) of unknown pathogenicity.A novel GCAP1 mutation, I143NT, caused a form of autosomal dominant cone degeneration that destroys foveal cones by mid-life but spares some cones in the peripheral retina up to 75 years. Properties of the GCAP1-I143NT mutant protein suggested that it is incompletely inactivated by high Ca2+ concentrations as should occur with dark adaptation. The continued activity of the mutant GCAP1 likely results in higher-than-normal scotopic cGMP levels which may, in turn, account for the progressive loss of cones.

Objective To search for factors that contribute to the development of neovascularage-related macular degeneration (AMD). Methods In a matched-pair case-control study, we studied sib pairs in whichthe index sibling had neovascular AMD in at least 1 eye and the unaffectedsibling had normal maculae (or at most only a few small drusen) and was pastthe age at which the index case was diagnosed. Factors studied included sex,iris color, education, alcohol consumption, body mass index, vitamin use,smoking history, hypercholesterolemia, aspirin use, hypertension, other cardiovasculardisease, any autoimmune disease, and non–insulin-dependent diabetesmellitus. Conditional logistic regression was performed to identify predictorsof neovascular AMD. Results On the basis of 73 sib pairs, multivariate regression analysis revealeda statistically significant 2% increase in risk of neovascular AMD with eachpack-year of smoking (odds ratio, 1.02; 95% confidence interval, 1.01-1.04; P = .007). Suggestive but nonsignificant associations werealso observed for mean lifetime alcohol consumption, adult lifetime body massindex, and hypertension in multivariate regression analyses. Conclusion Using extremely discordant sib pairs to study risk factors for AMD,a novel approach in epidemiological design, we found evidence that smokingis a risk factor for neovascular AMD.

To evaluate the molecular genetic defects associated with retinitis punctata albescens (RPA) in 5 patients from 3 families with this disease.We examined 3 probands and 2 clinically affected relatives with RPA. Clinical examinations included best-corrected visual acuity, visual field testing, electroretinography, dilated fundus examination, and fundus photography. Leukocyte DNA was analyzed for mutations in the exons of the genes encoding cellular retinaldehyde-binding protein 1 (RLBP1), 11-cis-retinol dehydrogenase (RDH5), interphotoreceptor retinoid-binding protein (RBP3), and photoreceptor all-trans-retinol dehydrogenase (RDH8). Not all patients were evaluated for mutations in each gene. The exons were individually amplified and screened for mutations by single-stranded conformational polymorphism analysis or direct genomic sequencing.The 3 probands had similar clinical findings, including a history of poor night vision, the presence of punctate white deposits in the retina, and substantially reduced or absent rod responses on electroretinogram testing. One of the probands (patient 2:III:2) had 2 novel mutations in the RLBP1 gene (Arg151Trp and Gly31[2-base pair deletion], [GGA--G-]). Segregation analysis showed that the 2 mutations were allelic and that the patient was a compound heterozygote. Both parents of the proband manifested round white deposits in the retina. The other 2 probands had no detected pathogenic mutations in RLBP1 or in the other 3 genes evaluated.The identification of novel RLBP1 mutations in 1 of our 3 probands, all with RPA, is further evidence of genetic (nonallelic) heterogeneity in this disease. The presence of round white deposits in the retina may be observed in those heterozygous for RLBP1. Clinical Relevance Patients with a clinical presentation of RPA can have genetically different mutations. Drusen-like lesions may be observed in heterozygotes in families with this disease and a mutation in RLBP1.

Objectives To determine if enhanced s-cone syndrome (ESCS), Goldmann-Favre syndrome(GFS), and clumped pigmentary retinal degeneration (CPRD) are caused by mutations in the NR2E3 gene and to characterize the clinical findings in patients with NR2E3 mutations. Patients One patient with ESCS, one with GFS, and 20 with CPRD. Methods The coding regions of the NR2E3 and NRL genes and part of the THRB1 coding region were scanned for mutations using single-strand conformation and direct sequencing methods. We evaluated visual acuity, refractive error, visual fields, fundi, final dark-adaptation thresholds, and electroretinograms (ERGs). Results The patients with ESCS and GFS and 9 of the 20 unrelated patients with CPRD had mutations in the NR2E3 gene. Six mutations were found in these 11 patients, including 2 novel mutations: the missense mutation Ala256Glu and the frameshift mutation Pro276del17 (the first obviously null allele reported). Three patients were mutant homozygotes, and 8 had 2 mutations. All but one of the mutations in the patients with ESCS and GFS were also found in patients with CPRD. All NR2E3 cases were hyperopes and had retinal vascular attenuation and reduced and delayed full-field ERGs. Clumped pigment deposits were recognized in the patients with ESCS and GFS. The CPRD patients without NR2E3 mutations had no detected mutations in NRL or THRB1 . Conclusions We found that ESCS, GFS, and CPRD can all have the same genetic basis. Clinical Relevance The combination of night blindness, hyperopia, and clumped retinal pigment deposits should raise the suspicion that a patient has NR2E3 disease.

Purpose. To compare the histopathology of three PMMA collar button type keratoprosthesis (KPro)/corneal specimens, explanted due to various complications, with that from one KPro/corneal specimen taken postmortem from an otherwise “healthy” enucleated eye. Methods. Patient 1 (chemical injury) had no problems for 3 years after KPro placement; the entire eye was obtained postmortem. Patient 2 (repeated graft failures, nonautoimmune disease) developed an “unlaserable” retroprosthesis membrane 4 months after KPro placement. A new KPro was placed. Patient 3 [ocular cicatricial pemphigoid (OCP)] developed tissue melt at the KPro–cornea interface 7 months after KPro placement, and the KPro was replaced. Patient 4 (OCP) developed progressive corneal melt around the KPro 3.5 years after placement resulting in replacement. All KPro/cornea specimens were processed and sectioned for histology with the KPro in place. Results. All patients exhibited growth of corneal or conjunctival derived epithelium under the KPro front plate. In patients 1 and 2, no epithelial downgrowth was noted and the keratocyte density appeared normal with few inflammatory cells present. Dense fibrous tissue was present behind the KPro in patient 2. Patients 3 and 4 showed massive inflammatory cell infiltration and tissue necrosis with “melt” adjacent to the stem resulting in epithelial downgrowth. Conclusions. Corneal inflammation and degradation after KPro placement correlate well with the preoperative diagnostic category. Patients with immune-related corneal surface disease can exhibit marked inflammatory responses leading to necrosis, stromal melting, and the formation of an epithelial fistula. In contrast, patients without autoimmune corneal disease demonstrate a remarkably noninflamed cornea with intact keratocytes and without epithelial ingrowth, commensurate with their clinical appearance.

To measure the rate of progression of retinal degeneration in patients with retinitis pigmentosa due to dominant rhodopsin mutations and to determine whether the rate of progression correlates with the location of the altered amino acid in the rhodopsin molecule.Change in ocular function was observed for an average of 8.7 years in 140 patients. After censoring data to eliminate "ceiling" and "floor" effects, longitudinal rates of change were compared, after weighting by follow-up time and number of visits, with rates inferred from cross-sectional analyses of the data from baseline visits. Mean rates of change were compared among groups of patients with mutations affecting the globule, plug, or C-terminal region of the protein after adjusting for age, gender, and baseline function.Mean annual exponential rates of decline were 1.8% for visual acuity, 2.6% for visual field area, and 8.7% for ERG amplitude. The rates of visual acuity and ERG amplitude decline were significantly faster, and the rate of visual field area decline was significantly slower, than those inferred from baseline visits. Rates of acuity loss did not vary significantly with the region affected by the mutation. In contrast, the mean annual rate of field loss in the C terminus group (7.4%) was significantly faster than that in the globule (1.7%) or plug (1.1%) group. The mean annual rate of ERG decline was also significantly faster in the C terminus group (13.5%) than in the globule (8.5%) or plug (3.7%) groups and significantly faster in the globule group than in the plug group.Rates of decline in visual function for groups of patients with rhodopsin mutations cannot be accurately inferred from cross-sectional analyses of baseline visits. Average rates of decline of visual field area and ERG amplitude are fastest in patients with mutations affecting the C-terminal region.

To study the possible involvement of the rod (SLC24A1) and cone (SLC24A2) Na-Ca+K exchanger (NCKX) genes in retinal diseases.DNA was collected from unrelated patients with retinal disease, mainly from North America. A human genomic library was screened with the cone NCKX cDNA, and hybridizing clones were sequenced to determine the genomic organization of the SLC24A2 gene. The single-strand conformation polymorphism (SSCP) technique and direct sequencing were used to screen the patients' DNA for mutations in SLC24A1 and SLC24A2. The effect of selected missense changes on protein function was tested by measuring potassium-dependent Na-Ca exchange of the mutant proteins expressed in insect cells.Twenty-seven novel sequence changes were found in the rod NCKX gene, 21 of which are unlikely to be pathogenic, because they did not cosegregate with the disease or did not affect conserved regions of the protein. Of the remaining six, two were frameshift mutations found in one patient each. If translated, these alleles would encode nonfunctional proteins. Three of the six possibly pathogenic mutations were missense changes located in conserved regions, and their protein functions were assayed. Only one (Ile992Thr) had a significantly low level of exchanger function, but it was found in two unrelated patients who were heterozygotes with different retinal diseases, and this mutation could not be unequivocally associated with either disease. The last of the six changes is likely to create a new splice acceptor site. The genomic organization of the cone NCKX gene was determined, and it contained 11 exons with a few splice variants. Fifteen novel sequence changes were identified in the cone exchanger gene in patients with a cone dysfunction or degeneration. Only three of these sequence changes, all missense changes found in heterozygous patients, were considered possibly pathogenic. Functional analysis showed only a slight reduction in the activity of the corresponding mutant proteins.Although variant alleles of the rod and cone NCKX genes were found, none could be definitively associated with a specific retinal disease. The human phenotype associated with mutant exchanger alleles remains unknown.

Background Genetic testing for inherited predisposition to diverse cancers has recently become available as a clinical service. We conducted a follow-up study of the initial series of US families who underwent RB1 genetic testing to evaluate long-term effects of the service. Procedure We enrolled 52 of 71 eligible families who responded to a follow-up study questionnaire administered 3–10 years after receipt of their RB1 results. Each family had one proband with unilateral, non-familial retinoblastoma, which is associated with a 12% pre-test probability of hereditary retinoblastoma. RB1 testing identified germline RB1 mutations in five patients, lowered the carrier probability to 2% in 21 patients, and did not substantially modify the carrier probability in the remaining 26. Results Diverse medical specialists offered and arranged for RB1 testing, and their recommendation was the most influential factor in the decision to be tested. Pre-test counseling was provided by ophthalmologists (30), oncologists (11), and geneticists and genetic counselors (11). Most respondents, regardless of test result, were satisfied and perceived gains from their genetic testing. Based on small numbers, families with reduced likelihood of hereditary retinoblastoma reported more positive outcomes. Parents of RB1 carriers were more likely to seek medical services, worry, and decide against having more children. Conclusions This study demonstrates the feasibility of follow-up studies of families who had genetic testing. Results from our small series suggest that genetic information and counseling are important components of RB1 clinical genetic testing, and long-term adverse effects of testing are uncommon. Med Pediatr Oncol 2001;37:372–378. © 2001 Wiley-Liss, Inc.

PURPOSE: To search for patients with Usher syndrome type IC among those with Usher syndrome type I who reside in New England. METHODS: Genotype analysis of microsatellite markers closely linked to the USH1C locus was done using the polymerase chain reaction. We compared the haplotype of our patients who were homozygous in the USH1C region with the haplotypes found in previously reported USH1C Acadian families who reside in southwestern Louisiana and from a single family residing in Lebanon. RESULTS: Of 46 unrelated cases of Usher syndrome type I residing in New England, two were homozygous at genetic markers in the USH1C region. Of these, one carried the Acadian USH1C haplotype and had Acadian ancestors (that is, from Nova Scotia) who did not participate in the 1755 migration of Acadians to Louisiana. The second family had a haplotype that proved to be the same as that of a family with USH1C residing in Lebanon. Each of the two families had haplotypes distinct from the other. CONCLUSION: This is the first report that some patients residing in New England have Usher syndrome type IC. Patients with Usher syndrome type IC can have the Acadian haplotype or the Lebanese haplotype compatible with the idea that at least two independently arising pathogenic mutations have occurred in the yet-to-be identified USH1C gene.

Mutations in CRX, a photoreceptor-specific transcription factor, can cause Leber congenital amaurosis (LCA), cone-rod dystrophy (CORD), and retinitis pigmentosa (RP), all of which feature severe visual impairment. Upon screening 55 patients with Leber congenital amaurosis, 75 patients with cone-rod dystrophy, 13 with cone dystrophy, and 36 with recessive or isolate RP for changes in the CRX sequence, we found two patients with Leber congenital amaurosis who carried heterozygously one of two novel frameshift mutations. The first mutation, Tyr191(1-bp del), was a de novo change and the second change, Pro263(1-bp del) was inherited from the proband’s affected father. Both mutations are predicted to encode mutant versions of CRX with altered carboxy termini. We also found a previously reported missense mutation, Arg41Gln, heterozygously in a 47-year-old patient with a form of RP. The missense change Val242Met was found in an isolate case of CORD and no controls; however, its pathogenicity remains uncertain because only limited segregation analysis was possible. A nonpathogenic missense change, Ala158Thr, was found to be a variant present at relatively high frequency among African-Americans. © 2001 Wiley-Liss, Inc.

PURPOSE: To compare histologic findings in an autopsy eye of an 84-year-old man with advanced retinitis pigmentosa and rhodopsin, Glu181Lys, with two cases of autosomal dominant retinitis pigmentosa (one with rhodopsin, Pro23His, and one with rhodopsin, Cys110Arg) and with a normal control, all of comparable age. METHODS: All eyes were prepared for light and electron microscopy within 6 hours after death. RESULTS: Extensive photoreceptor degeneration was revealed in the eyes with retinitis pigmentosa. Some macular cones showed membranous swirls only in the eye with rhodopsin, Glu181Lys. CONCLUSION: The retinal degeneration caused by rhodopsin, Glu181Lys, can feature membranous swirls in the inner segments of cones in the macula. These swirls have not been reported in other cases of dominant retinitis pigmentosa studied so far, and their pathogenesis remains to be defined.

Usher syndrome type I (USH1) is a recessively-inherited disorder consisting of retinitis pigmentosa, profound congenital deafness, and vestibular ataxia. It can be caused by mutations in at least six different loci (USH1A–1F). The gene encoding human myosin VIIA ( MYO7A ) is the USH1B locus. In this study, 66 unrelated patients with USH1 were evaluated for defects in MYO7A using single-strand conformation polymorphism analysis and direct genomic sequencing. Twenty-nine per cent of cases were found to have likely pathogenic MYO7A mutations. A total of 22 likely pathogenic changes were identified, 18 of which were novel. Cosegregation analysis of mutations in five available families showed that the MYO7A changes segregated with the disease in an autosomal recessive fashion. Average visual function as measured by visual acuity, visual field area, and ERG amplitude was not significantly different between the group of patients with likely pathogenic MYO7A changes and the group in which no likely pathogenic MYO7A changes were detected.

The autosomal dominant retinitis pigmentosa (RP) locus, designated RP1, has been mapped through linkage studies to a 4-cM interval at 8q11–13. Here we describe a new photoreceptor-specific gene that maps in this interval and whose expression is modulated by retinal oxygen levels in vivo. This gene consists of at least 4 exons that encode a predicted protein of 2,156 amino acids. A nonsense mutation at codon 677 of this gene is present in approximately 3% of cases of dominant RP in North America. We also detected two deletion mutations that cause frameshifts and introduce premature termination codons in three other families with dominant RP. Our data suggest that mutations in this gene cause dominant RP, and that the encoded protein has an important but unknown role in photoreceptor biology.

Although mosaicism can have important implications for genetic counseling of families with hereditary disorders, information regarding the incidence of mosaicism is available for only a few genetic diseases. Here we describe an evaluation of 156 families with retinoblastoma; the initial oncogenic mutation in the retinoblastoma gene had been identified in these families. In 15 ( approximately 10%) families, we were able to document mosaicism for the initial mutation in the retinoblastoma gene, either in the proband or in one of the proband's parents. The true incidence of mosaicism in this group of 156 families is probably higher than our findings indicate; in some additional families beyond the 15 we identified, mosaicism was likely but could not be proven, because somatic or germ-line DNA from key family members was unavailable. Germ-line DNA from two mosaic fathers was analyzed: in one of these, the mutation was detected in both sperm and leukocyte DNA; in the other, the mutation was detected only in sperm DNA. Our data suggest that mosaicism is more common than is generally appreciated, especially in disorders such as retinoblastoma, in which a high proportion of cases represent new mutations. The possibility of mosaicism should always be considered during the genetic counseling of newly identified families with retinoblastoma. As demonstrated here, genetic tests of germ-line DNA can provide valuable information that is not available through analysis of somatic (leukocyte) DNA.

New germline mutations in the human retinoblastoma gene are known to arise preferentially on paternally derived chromosomes, but the magnitude of that bias has not been measured. We evaluated 49 cases with a new germline mutation and found that in 40 cases (82%) the mutation arose on the paternally derived allele. We also evaluated 48 cases likely to have a somatic initial mutation; in this group the initial mutation arose on paternal or maternal chromosomes with approximately equal frequency. There was no statistically significant difference in the average age of fathers of children with new paternal germline mutations from the average age of fathers of children with new maternal germline mutations or somatic initial mutations. Combining the data with that from previous reports from other groups, the proportion of new germline mutations arising on a paternally derived allele is 85% (based on 72 cases; 95% confidence interval = 76-93%). This number can be useful in the genetic counseling of some families with retinoblastoma.