Neuropathy target esterase activity defines phenotypes among PNPLA6 disorders

Biallelic pathogenic variants in the PNPLA6 gene cause a broad spectrum of disorders leading to gait disturbance, visual impairment, anterior hypopituitarism and hair anomalies. PNPLA6 encodes neuropathy target esterase (NTE), yet the role of NTE dysfunction on affected tissues in the large spectrum of associated disease remains unclear. We present a systematic evidence-based review of a novel cohort of 23 new patients along with 95 reported individuals with PNPLA6 variants that implicate missense variants as a driver of disease pathogenesis. Measuring esterase activity of 46 disease-associated and 20 common variants observed across PNPLA6-associated clinical diagnoses unambiguously reclassified 36 variants as pathogenic and 10 variants as likely pathogenic, establishing a robust functional assay for classifying PNPLA6 variants of unknown significance. Estimating the overall NTE activity of affected individuals revealed a striking inverse relationship between NTE activity and the presence of retinopathy and endocrinopathy. This phenomenon was recaptured in vivo in an allelic mouse series, where a similar NTE threshold for retinopathy exists. Thus, PNPLA6 disorders, previously considered allelic, are a continuous spectrum of pleiotropic phenotypes defined by an NTE genotype:activity:phenotype relationship. This relationship, and the generation of a preclinical animal model, pave the way for therapeutic trials, using NTE as a biomarker.

Panuveitis and optic neuropathy following SARS-COV-2 in the absence of multisystem inflammatory syndrome in a child

Purpose

To describe the presentation of a healthy 8-year-old female referred to a pediatric ophthalmology clinic with blurred vision and concern for bilateral uveitis.

Observations

The patient was diagnosed with COVID-19 two weeks prior to the onset of ocular symptoms. An examination revealed bilateral pan-uveitis and patient underwent an extensive work-up for an underlying cause that was unremarkable. Two years following the initial presentation, she has not had any evidence of recurrence.

Conclusions and Importance

This case highlights the potential for COVID-19 to be temporally associated with ocular inflammation and underscores the importance of recognizing and investigating such manifestations in pediatric patients. The mechanism by which COVID-19 may lead to an immune response that affects the eyes is not fully understood, but it is believed to be related to an overactive immune response triggered by the virus. Further studies are needed to better understand the potential relationship between COVID-19 and ocular manifestations in pediatric patients.

Carbonic anhydrase inhibitors limit complications in X-linked retinoschisis

Purpose

Carbonic anhydrase inhibitors (CAIs) reduce macular schisis in patients with X-linked retinoschisis (XLRS). The purpose of this study was to determine if CAIs reduce the incidence of complications from XLRS, including macular atrophy, retinal tears, and retinal detachment (RD), the most common causes of vision loss in patients with XLRS.

Methods

For this retrospective interventional case series, a chart review of patients examined at Cincinnati Children's Hospital Medical Center [CCHMC] and Cincinnati Eye Institute [CEI] between 1/1/2015 and 1/16/2023 was performed. Male patients were included based on genetically-confirmed RS1 or typical clinical presentation with known family history of XLRS with at least two follow-up visits.

Results

Twenty-eight patients (56 eyes) with XLRS were included. There were 10 RS1 variants among the 21 genotyped patients. Median age at clinical diagnosis was 10.4 years old (range: 0.4-55.7 years) with median follow-up time of 4.7 years (range: 0.2-38.3 years). Median presenting Snellen visual acuity was 20/60 (logMAR 0.48, range: 0.18-3). In 26 eyes of 15 patients treated with CAIs, median CST pre-treatment was 416 microns (range: 198-701 microns), and median percentage decrease in CST on treatment was 21.8% (range: 0-74.5%) from highest pre-treatment CST. Reduction in CST with CAI use was statistically significant (p = 0.02), but not logMAR VA (p = 0.64). There was no significant difference in CST between patients treated with topical vs. oral CAI (p = 0.95) or between patients with partial or complete CAI adherence (p = 0.60). Ten eyes of seven patients had an RD requiring surgical intervention. No treated eyes developed new macular atrophy, peripheral retinoschisis, retinal tears, or RD; two eyes on topical CAIs had spontaneous resolution of bullous peripheral retinoschisis.

Conclusion

During the follow-up period, patients taking CAIs reduced macular schisis and did not experience new complications of macular atrophy, retinal tears, or RD. This is a relatively large cohort with long-term follow-up periods for patients with XLRS. Reduced macular schisis may not require perfect adherence with CAIs. A large, prospective, randomized, controlled clinical trial is needed to determine the potential of CAIs to improve visual function, reduce retinoschisis, and prevent RD.

Dual phenotype: co-occurring Leber congenital amaurosis and familial exudative vitreoretinopathy: a case report

PURPOSE

To report the concurrent presentation and management of IQCB1-associated Leber Congenital Amaurosis and NDP-associated Familial Exudative Vitreoretinopathy (FEVR).

MATERIALS AND METHODS

A 6-month-old Caucasian infant presented with poor visual response, high hypermetropia, and infantile-nystagmus with a provisional diagnosis of Leber Congenital Amaurosis based on clinical findings. Genetic counseling and testing were performed with a 285 gene retinal dystrophy panel (Blueprint Genetics). Clinical characteristics, presentation, ancillary testing results, and management are described.

RESULTS

Two previously reported heterozygous pathogenic variants in ICQB1 were identified (c.1518_1519del (p.His506Glnfs*13) and c.1381C>T, p.Arg461*) segregating in trans. In addition, a variation of uncertain significance (VUS) was found in NDP (c.280C>T; p.His94Tyr). Fluorescein angiography was performed demonstrating peripheral avascularity and retinal telangiectasia without frank neovascularization. Peripheral ablative laser was applied to the avascular zone.

CONCLUSIONS

The NDP VUS likely represents a pathogenic variant given the FEVR phenotype in addition to retinal degeneration, creating a rare dual phenotype. The combination of low oxygen demand from the IQCB1-associated retinal degeneration and NDP variant may have led to a more attenuated FEVR presentation with uncertain prognosis. A molecular diagnosis informed ocular and renal surveillance, as well as the recurrence risk for future offspring.

Alternative Biologic Therapy in Children Failing Conventional TNFα Inhibitors for Refractory, Noninfectious, Chronic Anterior Uveitis

PURPOSE

A significant number of children with noninfectious, chronic anterior uveitis (CAU) fail to respond to conventional therapy; however, successful alternative biologic treatments (ABT) have not been well described. This study aims to review the clinical and treatment characteristics of children with CAU who require ABT.

DESIGN

Retrospective, nonrandomized clinical study.

METHODS

Setting: Tertiary center.

STUDY POPULATION

Children with noninfectious CAU.

OBSERVATION PROCEDURES

Clinical characteristics, uveitis course, complications, and treatment were compared among patients treated with methotrexate (MTX) monotherapy, conventional TNFα inhibitors (cTNFi), and ABT for >3 months.

MAIN OUTCOME MEASURE

Success of ABT (abatacept, tocilizumab, and/or golimumab) in children failing conventional treatment.

RESULTS

Of the 52 children with CAU, 75% had juvenile idiopathic arthritis. CAU was controlled in 15 children receiving MTX monotherapy, 28 receiving cTNFi, and 9 receiving ABT (n = 1, abatacept; n = 3, tocilizumab; n = 5, golimumab). Patients in the ABT group had a greater number of total ocular complications per person before ABT than those in the control groups (3.4 vs 0.7 [MTX], P < .001, and 1.5 [cTNFi], P < .001, respectively). In all 9 children on ABT, treatment led to control of CAU and topical glucocorticoids tapered to ≤2 drops/d with no new ocular complications.

CONCLUSIONS

In this study, alternative biologics (abatacept, golimumab, and tocilizumab) were useful for treating CAU in children who fail MTX and cTNFi therapy. Patients who were controlled on ABT had more disease activity, ocular complications, and anti-cTNFi neutralizing antibodies (before ABT) than those managed with conventional therapy. Larger studies are required to confirm these findings.

The risk of uveitis due to prostaglandin analogs in pediatric glaucoma

PURPOSE

To examine the incidence of uveitis in children prescribed prostaglandin analogs (PGAs) for glaucoma.

METHODS

In this dual-center cohort study, the medical records of consecutive patients <18 years old treated with a PGA between January 1, 2012, and December 31, 2018, were reviewed retrospectively. Patients with all forms of glaucoma, including those with a prior history of uveitis, were included. Patients who had been on a PGA prior to their first recorded visit were excluded. Patient charts were reviewed for new or recurrent uveitis during the first year of PGA therapy.

RESULTS

A total of 103 children (147 eyes) were included, with a total PGA exposure of 1,352 child-months. Ninety-eight children (142 eyes) tolerated the PGA without an episode of uveitis. Five patients with a documented prior history of uveitis experienced a unilateral episode of uveitis. A review of their medical records identified prescribed or unscheduled decrease in topical steroids or immunosuppressive medication as the most likely cause of uveitis recurrence.

CONCLUSIONS

This study provides further evidence that PGAs are unlikely to induce uveitis in children being treated for glaucoma and suggests that this may also be true in those with a history of uveitis. We are unable to evaluate whether PGAs make recurrence more likely or the tapering of steroids more difficult.

Comprehensive assessment of quality of life, functioning and mental health in children with juvenile idiopathic arthritis and non-infectious uveitis

OBJECTIVE

Pediatric uveitis can lead to sight-threatening complications and impact quality of life (QOL) and functioning. We aim to examine health-related QOL (HRQOL), mental health, physical disability, vision-related functioning (VRF), and vision-related QOL (VRQOL) in children with juvenile idiopathic arthritis (JIA), JIA-associated uveitis (JIA-U), and other non-infectious uveitis. We hypothesize that there will be differences based on the presence of eye disease.

METHODS

A multicenter cross-sectional study was conducted at four sites. Patients with JIA, JIA-U, or non-infectious uveitis were enrolled. Patients and parents completed the PedsQL (HRQOL), RCADS (anxiety/depression), CHAQ (physical disability), and EYE-Q (VRF/VRQOL). Clinical characteristics and patient-reported outcome measures (PROMs) were compared by diagnosis.

RESULTS

Of 549 patients, 332 had JIA, 124 JIA-U, and 93 other uveitis. Children with JIA-U had worse EYE-Q scores compared to JIA only. In children with uveitis, those with anterior uveitis (JIA-U and uveitis only) had less ocular complications, better EYE-Q scores, and worse CHAQ and PedsQL physical summary scores compared to those with non-anterior disease. In children with anterior uveitis, those with JIA-U had worse PedsQL physical summary and CHAQ scores than anterior uveitis only. Further, EYE-Q scores were worse in children with bilateral uveitis and more visual impairment. There were no differences in RCADS scores among groups.

CONCLUSION

We provide a comprehensive outcome assessment of children with JIA, JIA-U, and other uveitis diagnoses. Differences in QOL and function were noted based on underlying disease. Our results support the addition of a vision-specific measure to better understand the impact of uveitis.

Assessing the validity and reliability of the Effects of Youngsters' Eyesight on Quality of Life (EYE-Q) questionnaire among children with uveitis

PURPOSE

The Effects of Youngsters' Eyesight on Quality of Life (EYE-Q) questionnaire measures vision-related functioning (VRF) and vision-related quality of life (VRQOL) in children with uveitis. Our aim was to revise the Alpha version of the EYE-Q to refine VRF and VRQOL subscales and assess the validity of the EYE-Q.

METHODS

Children with juvenile idiopathic arthritis (JIA), JIA-associated uveitis, and other non-infectious uveitis were enrolled. Patients and parents completed the EYE-Q, PedsQL (overall QOL), and CHAQ (physical functioning). The Development site completed the Alpha version of the EYE-Q, and the Composite sites completed the Beta version. We compared item-subscale correlations, internal consistency, construct and discriminant validity amongst the different versions.

RESULTS

Of the 644 patients enrolled, 61.6% completed the Alpha version, and 38.4% the Beta version of the EYE-Q. Mean patient age was 11.1 (SD = 4.2) years, and 70% were female. Fewer white patients (73.5%) completed the Alpha version compared to the Beta version (86.2%, p <0.001). With the exception of patient-reported VRF, both versions had similar item-subscale correlations. Version comparisons on scale internal consistencies indicated significant differences for parent- and patient-reported VRF, but each scale had a Cronbach's Alpha >0.80 Beta. When data were combined, the EYE-Q showed significant differences between JIA-only and uveitis patients on all parent and patient scores, except for patient-reported VRF.

CONCLUSION

The EYE-Q appears to be a valid measure of VRF and VRQOL in pediatric uveitis. Our results suggest it may be used as an outcome measure in multi-center pediatric uveitis studies.

Systemic and ocular manifestations of a patient with mosaic ARID1A-associated Coffin-Siris syndrome and review of select mosaic conditions with ophthalmic manifestations

Mosaic genetic mutations may be somatic, germline, or "gonosomal" and have the potential to cause genetic syndromes, disorders, or malformations. Mutations can occur at any point in embryonic development and the timing determines the extent of distribution of the mutation throughout the body and different tissue types. The eye and visual pathway offer a unique opportunity to study somatic and gonosomal mosaic mutations as the eye consists of tissues derived from all three germ layers allowing disease pathology to be assessed with noninvasive imaging. In this review, we describe systemic and ocular manifestations in a child with mosaic Coffin-Siris syndrome. The patient presented with a significant medical history of accommodative esotropia and hyperopia, macrocephaly, polydactyly, global developmental delay, hypotonia, ureteropelvic junction (UPJ) obstruction, and brain MRI abnormalities. The ophthalmic findings in this patient were nonspecific, however, they are consistent with ocular manifestations reported in other patients with Coffin-Siris syndrome. We also review ophthalmic findings of select mosaic chromosomal and single-gene disorders. Ophthalmic assessment alongside clinical genetic testing may play an important role in diagnosis of genetic syndromes as well as understanding disease pathology, particularly when mosaicism plays a role.

Chlamydia Conjunctivitis in 2 Prepubertal Children: An Uncommon Presentation of Child Sexual Abuse

Sexually transmitted infection as the result of child sexual abuse in prepubertal children is uncommon. Chlamydia trachomatis conjunctivitis is an even less common entity in prepubertal children outside the newborn period. This report details the presentation of 2 children with conjunctivitis who were subsequently diagnosed as having C. trachomatis conjunctivitis. One child was also diagnosed as having rectal and pharyngeal C. trachomatis infection, and the other also had genital C. trachomatis infection. Even with multisite C. trachomatis infection as an indication of sexual abuse, neither child gave a detailed disclosure of abuse to account for their infections. The absence of a clear disclosure is not uncommon. Previous literature reports that a disclosure in these circumstances occurs in less than half of cases. In this report, we review the recommendations for diagnosis of C. trachomatis using nucleic acid amplification testing and culture as well as treatment. Specific clinical features should alert the clinician to C. trachomatis conjunctivitis and lead to timely diagnosis and protection of the child from further sexual abuse.

S100 proteins, cytokines, and chemokines as tear biomarkers in children with juvenile idiopathic arthritis-associated uveitis

PURPOSE

Biomarkers for juvenile idiopathic arthritis-associated uveitis (JIA-U) are needed. We aimed to measure inflammatory biomarkers in tears as a non-invasive method to identify biomarkers of uveitis activity.

METHODS

Tears were collected from children with JIA-U (n=20) and pediatric controls (n=20) using Schirmer strips. S100A8, A9, A12, IL-18, IL-8, IP-10, MCP-1, RANTES, and sICAM-1 were measured by ELISA and Luminex assays. Levels of biomarkers were compared between children with JIA-U and controls, and active and inactive JIA-U.

RESULTS

IL-8, sICAM-1, and S100A12 levels were similar between JIA-U and controls, but differed by activity. Active JIA-U had significantly increased S100A12 compared to inactive JIA-U (mean 27,722.5 pg/ML (SE 1.3) vs. 5,937.2 (1.3), p=0.002), IL-8 (73.5 [1.2] vs. 36.2 [1.2], p=0.009), and sICAM-1 (15,822.7 [1.2) vs. 8,778.0 [1.6], p=0.024).

CONCLUSION

We detected inflammatory biomarkers non-invasively in tears of children with JIA-U. IL-8, sICAM-1, and S100A12 are potential biomarkers for uveitis activity.

Effectiveness of long-term infliximab use and impact of treatment adherence on disease control in refractory, non-infectious pediatric uveitis

BACKGROUND

Refractory non-infectious uveitis is a serious condition that leads to ocular complications and vision loss and requires effective systemic treatment to control disease. The effectiveness of long-term infliximab [IFX] in refractory non-infectious childhood uveitis and the impact of treatment adherence on disease control were evaluated.

METHODS

Retrospective, single-center study between December 2002 and April 2016 of 27 children with refractory non-infectious uveitis [17 with juvenile idiopathic arthritis, JIA] treated with long-term IFX [9+ months]. Disease activity was assessed prior to and while on IFX using the Standardization of Uveitis Nomenclature [SUN]. Number of visits per year with active uveitis was analyzed by repeated measures logistic regression analysis from 2 years prior to IFX initiation or from onset of uveitis until most recent visit on IFX. Incomplete treatment adherence was assessed for each visit and defined as any deviance in corticosteroid use, prescribed infusion frequency, and/or follow-up examination frequency.

RESULTS

Primary outcomes were sustained uveitic and systemic disease control prior to and during IFX treatment and the impact of incomplete adherence on uveitic disease control while on IFX. Secondary outcomes included corticosteroid and glaucoma medication requirement, ocular complications and need for surgical intervention. Mean age at IFX initiation was 10.4 ± 4.5 years; initial mean dose was 6.6 ± 2.2 mg/kg [and given at weeks 0, 2, 4 and q4 weeks thereafter for 93%]. Median duration on IFX was 35 [range 9-128] months. Prior to IFX, 14/27 patients had failed adalimumab ± methotrexate [MTX]; 21/27 failed MTX. IFX led to uveitis control in 89% and arthritis control in 76% (13/17). The odds ratio of having controlled disease after IFX was 4.1 (2.6, 6.4) compared to pre-treatment visits. Topical corticosteroids and glaucoma medications were statistically decreased (p = 0.007 right eye [OD], 0.003 left eye [OS] and p = 0.001 OD, p = 0.028 OS respectively). Incomplete adherence to treatment showed 10.3 times greater odds (7.1, 15.0) of having disease activity than full adherence.

CONCLUSIONS

This study adds significantly to the IFX literature by documenting outstanding uveitis control with long-term IFX treatment in non-infectious pediatric uveitis patients. Higher dosage and shorter interval were utilized without adverse effects. Importantly, this is the first study, to our knowledge, to document the significant impact of treatment adherence on uveitis control.

Presentation of TRPM1-Associated Congenital Stationary Night Blindness in Children

IMPORTANCE

Congenital stationary night blindness (CSNB) implies a stable condition, with the major symptom being nyctalopia present at birth. Pediatric clinical presentation and the course of different genetic subtypes of CSNB have not, to our knowledge, been well described in the era of molecular genetic diagnosis.

OBJECTIVE

To describe the presentation and longitudinal clinical characteristics of pediatric patients with molecularly confirmed TRPM1-associated complete CSNB (cCSNB).

DESIGN, SETTING, PARTICIPANTS

This study was conducted at the University of Iowa from January 1, 1990, to July 1, 2015, and was a retrospective, longitudinal case series of 7 children (5 [71.4%] female) with TRPM1-associated cCSNB followed up for a mean (SD) of 11.1 (2.8) years.

MAIN OUTCOMES AND MEASURES

History, ophthalmologic examination findings, full-field electroretinogram (ffERG) results, full-field stimulus threshold testing results, Goldmann visual field results, optical coherence tomography results, and molecular genetic results were evaluated. Presenting symptoms and signs, the correlation of refractive error with electroretinography, and clinical evolution were analyzed.

RESULTS

Seven patients (5 [71.4%] female) presented early in childhood with strabismus (n = 6 [86%]), myopia (n = 5 [71%]), and/or nystagmus (n = 3 [43%]). The mean (SD) age at presentation was 8 (4) months and for receiving a diagnosis by ffERG was 7.3 years, with molecular diagnosis at 9.7 years. The mean (SD) length of follow-up was 11 (2.8) years. The best-corrected visual acuity at the most recent visit averaged 20/30 in the better-seeing eye (range, 20/20-20/60). The mean (SD) initial refraction was -2.80 (4.42) diopters (D) and the mean refraction at the most recent visit was -8.75 (3.53) D (range, -4.00 to -13.75 D), with the greatest rate of myopic shift before age 5 years. Full-field electroretinogram results were electronegative, consistent with cCSNB, without a significant change in amplitude over time. No patient or parent noted night blindness at presentation; however, subjective nyctalopia was eventually reported in 5 of 7 patients (71%). The full-field stimulus threshold testing results were moderately subnormal (-29.7 [3.8] dB; normal -59.8 [4.0] dB). Goldmann visual field results were significant for full I-4e, but constricted I-2e isopter. Eight different mutations or rare variants in TRPM1 predicted to be pathogenic were detected, with 3 novel variants.

CONCLUSIONS AND RELEVANCE

Children with TRPM1-associated cCSNB presented before school age with progressive myopia as well as strabismus and nystagmus (but not nyctalopia), with stable, electronegative ffERG results, mildly subnormal full-field stimulus threshold testing results, and a constricted I2e isopter on perimetry. These findings suggest that ffERG and cCSNB genetic testing should be considered for children who present with early-onset myopia, especially in the presence of strabismus and/or nystagmus, and that TRPM1-associated cCSNB is a channelopathy that may present without complaints of night blindness in childhood.

Pharmacological approaches to restoring lens transparency: Real world applications

Cataract is the most common cause of blindness and a major cause of visual impairment worldwide. As the world's population ages, cataract-induced visual impairment is of increasing prevalence, and treatment is limited to those with access to surgical care. While cataracts are mainly a disease of the elderly, infantile cataracts lead to lifelong visual impairment if untreated. Even in those with surgical treatment early in life, visual prognosis is often guarded. Consequently, there is an increasing impetus for alternative therapeutic modalities. Makley and Zhao utilize two different experimental approaches to identify novel pharmacological substances able to improve lens transparency by reducing aggregation of crystalline proteins. These data support an alternative to surgical correction that may be applied to adult patients without access to surgical care as well as address the unique challenges of infantile cataracts.

Allergic eye disease

Ocular allergy is one of the most common conditions encountered by pediatricians and ophthalmologists and is characterized by bilateral injection with itching as the predominant symptom. Risk factors include history of atopy (asthma, eczema, seasonal allergies). Basic and clinical research have provided insight into the immunologic mechanisms, clinical presentation, differential diagnosis, and pharmacologicmanagement of this condition. New pharmacologic agents have improved the efficacy and safety of ocularallergy treatment. This article discusses the classification of ocular allergy diagnosis and management, and addresses clinical symptoms and signs that indicate more severe allergic disease or alternative diagnosis that should prompt expeditious referral to an ophthalmologist.

Surgical management of lens subluxation in Marfan syndrome

PURPOSE

To review the literature on the surgical management, describe a simplified surgical technique, and to report the postoperative clinical course of ectopia lentis removal in patients with Marfan syndrome.

METHODS

The medical records of patients with a clinical diagnosis of Marfan syndrome and clinically significant lens subluxation were retrospectively reviewed. Patients underwent lens extraction by a single surgeon via a simplified anterior segment approach. The pre- and postoperative best-corrected visual acuity, biometric measurements, intraocular pressure, and incidence of surgery-related complications were reviewed.

RESULTS

A total of 42 eyes of 22 patients were included. Mean postoperative follow-up was 4.9 ± 2.9 years (range, 1-10 years). Average age at surgery was 10.2 ± 9.2 years (range, 2-37 years), with 18 patients (36 eyes) ≤ 18 years of age. The average preoperative best-corrected visual acuity was 20/80, and the average postoperative best-corrected visual acuity at last follow-up was 20/25, with an average improvement of 6 lines on the Snellen chart. All eyes had a best-corrected visual acuity > 20/30 at last follow-up with aphakic correction. One eye of 1 patient developed a retinal detachment following blunt trauma. No other intra- or postoperative complications were reported.

CONCLUSIONS

Anterior lensectomy and limited vitrectomy with aphakic correction is safe and provides a consistent visual outcome in patients with lens subluxation secondary to Marfan syndrome. This is especially important in pediatric patients, in whom long-term follow-up for iris- and scleral-fixated intraocular lenses is limited.

Identification of three ABCA4 sequence variations exclusive to African American patients in a cohort of patients with Stargardt disease

PURPOSE

To describe the clinical and molecular findings in ten unrelated African American patients with Stargardt disease.

DESIGN

Retrospective, observational case series.

METHODS

We reviewed the clinical histories, examinations, and genotypes of 85 patients with molecular diagnoses of Stargardt disease. Three ABCA4 sequence variations identified exclusively in African Americans were evaluated in 300 African American controls and by in silico analysis.

RESULTS

ABCA4 sequence changes were identified in 85 patients from 80 families, of which 11 patients identified themselves as African American. Of these 11 patients, 10 unrelated patients shared 1 of 3 ABCA4 sequence variations: c.3602T>G (p.L1201R); c.3899G>A (p.R1300Q); or c.6320G>A (p.R2107H). The minor allele frequencies in the African American control population for each variation were 7.5%, 6.3%, and 2%, respectively. This is comparable to the allele frequency in African Americans in the Exome Variant Server. In contrast, the allele frequency of all three of these variations was less than or equal to 0.05% in European Americans. Although both c.3602T>G and c.3899G>A have been reported as likely disease-causing variations, one of our control patients was homozygous for each variant, suggesting that these are nonpathogenic. In contrast, the absence of c.6320G>A in the control population in the homozygous state, combined with the results of bioinformatics analysis, support its pathogenicity.

CONCLUSIONS

Three ABCA4 sequence variations were identified exclusively in 10 unrelated African American patients: p.L1201R and p.R1300Q likely represent nonpathogenic sequence variants, whereas the p.R2107H substitution appears to be pathogenic. Characterization of population-specific disease alleles may have important implications for the development of genetic screening algorithms.

Ocular manifestations of the antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease characterised by a heterogenous group of antibodies directed against negatively charged phospholipids including antiphospholipid antibodies (aPL), anticardiolipin antibodies (aCL) and β-2 glycoprotein I (aβ-2-GP1). The major features of this disorder include arterial and venous thrombosis and recurrent fetal loss. The vasculature of the eye is frequently involved and may be the presenting manifestation. A diagnosis of APS should be considered in a young patients without traditional thromboembolic risk factors presenting with ocular vaso-occlusive disease. Management of these patients involves a team-approach with a haematologist/oncologist or rheumatologist to manage the coagulation status of these patients to prevent further systemic vascular occlusions.