Resolving the dark matter of ABCA4 for 1054 Stargardt disease probands through integrated genomics and transcriptomics.

PURPOSE: Missing heritability in human diseases represents a major challenge, and this is particularly true for ABCA4-associated Stargardt disease (STGD1). We aimed to elucidate the genomic and transcriptomic variation in 1054 unsolved STGD and STGD-like probands. METHODS: Sequencing of the complete 128-kb ABCA4 gene was performed using single-molecule molecular inversion probes (smMIPs), based on a semiautomated and cost-effective method. Structural variants (SVs) were identified using relative read coverage analyses and putative splice defects were studied using in vitro assays. RESULTS: In 448 biallelic probands 14 known and 13 novel deep-intronic variants were found, resulting in pseudoexon (PE) insertions or exon elongations in 105 alleles. Intriguingly, intron 13 variants c.1938-621G>A and c.1938-514G>A resulted in dual PE insertions consisting of the same upstream, but different downstream PEs. The intron 44 variant c.6148-84A>T resulted in two PE insertions and flanking exon deletions. Eleven distinct large deletions were found, two of which contained small inverted segments. Uniparental isodisomy of chromosome 1 was identified in one proband. CONCLUSION: Deep sequencing of ABCA4 and midigene-based splice assays allowed the identification of SVs and causal deep-intronic variants in 25% of biallelic STGD1 cases, which represents a model study that can be applied to other inherited diseases.

Anterior uveitis: a manifestation of graft-versus-host disease.

PURPOSE: To describe the occurrence of anterior uveitis along with systemic manifestations of chronic graft-versus-host disease (GVHD) after nonmyeloablative allogeneic hematopoietic stem cell transplantation (HSCT) in 3 patients with hematologic malignancies. DESIGN: Retrospective small case series. PARTICIPANTS: Three patients who underwent HSCT and 4 age- and gender-matched controls for cytokine analysis in ocular fluid. METHODS: Interventional study of patients who underwent HSCT. Screening for evidence of infectious causes and immunological analysis of ocular fluid samples. MAIN OUTCOME MEASURES: Clinical features of uveitis and results of aqueous analysis. RESULTS: Anterior uveitis developed during an exacerbation of chronic GVHD in 3 patients after allogeneic HSCT for hematologic malignancies. Patients exhibited no abnormalities on extensive uveitis screening, and in addition, serologic and wide-ranging aqueous analysis showed no evidence of recent infections. We observed signs of inflammation in the ocular fluid in 2 of 3 patients by the determination of different cytokines. No other explanation for uveitis was found except the exacerbation of GVHD. Treatment, both systemic and topical, directed to chronic GVHD induced remission of uveitis in all patients along with amelioration of other signs of GVHD. CONCLUSIONS: Anterior uveitis occurred in the wake of the acute exacerbation of chronic GVHD after HSCT and may represent an ocular manifestation of chronic GVHD.

The value of measuring urinary ß2-microglobulin and serum creatinine for detecting tubulointerstitial nephritis and uveitis syndrome in young patients with uveitis.

IMPORTANCE: Tubulointerstitial nephritis and uveitis (TINU) syndrome is characterized by tubulointerstitial and ocular inflammation. Thus far, the value of noninvasive diagnostic tests is not known. OBJECTIVE: To determine whether urinary ß2-microglobulin (ß2M), urinary protein, and serum creatinine have predictive value for detecting TINU syndrome in young patients with uveitis. DESIGN, SETTING, AND PARTICIPANTS: This prospective cohort study was conducted July 2010 through February 2013 at a tertiary care referral center in Utrecht, the Netherlands. Forty-five consecutive new patients with uveitis aged 22 years or younger were enrolled. EXPOSURES: Urinary ß2M, urinary protein, and serum creatinine were measured prospectively, and the estimated glomerular filtration rate was calculated. MAIN OUTCOMES AND MEASURES: A post hoc analysis was performed to determine whether urinary ß2M, urinary protein, serum creatinine, estimated glomerular filtration rate, and/or pyuria were correlated with definitive and probable cases of TINU syndrome. RESULTS: Eighteen of the 45 patients (40%) in our cohort had elevated urinary ß2M levels, and 10 patients (22%) had elevated serum creatinine levels. Twenty of 43 patients (47%) had proteinuria. Eight of the 45 patients were diagnosed by a pediatric nephrologist as having renal dysfunction that suggested acute interstitial nephritis. Of these 8 patients, 2 were definitively diagnosed as having TINU syndrome (confirmed by renal biopsy). After excluding other causes of renal dysfunction, the remaining 6 patients with uveitis and renal dysfunction fulfilled the criteria of probable TINU syndrome. The 8 patients with definitive or probable TINU syndrome had higher urinary ß2M levels than patients with normal renal function (median ß2M, 1.95 mg/L; 95% CI, 1.26-5.16 mg/L vs 0.20 mg/L; 95% CI, 0.19-0.21 mg/L; P < .001; Mann-Whitney U test). Our analysis revealed that the positive predictive value of increased ß2M combined with increased serum creatinine was 100% for detecting definitive and/or probable TINU syndrome. CONCLUSIONS AND RELEVANCE: These data suggest that urinary ß2M and serum creatinine levels are sensitive and relatively simple diagnostic screening tools for detecting renal dysfunction to diagnose TINU syndrome in young patients with uveitis similar to those evaluated in this study.

Characteristics of childhood uveitis leading to visual impairment and blindness in the Netherlands.

PURPOSE: To investigate the clinical characteristics of childhood uveitis leading to visual impairment or blindness. METHODS: In this descriptive study, we reviewed data from the medical records of 58 children with visual impairment or blindness due to childhood uveitis, which were seen at an institute for visually impaired patients (Bartiméus) between January 1981 and December 2012, in a retrospective, cross-sectional manner. RESULTS: Thirty-two of the 58 children (55%) were visually impaired and 26 (45%) were legally blind. Uveitis was posterior in 76% of all cases. Infectious uveitis represented 74% of all cases, of which 86% was congenital. Five patients (9%) had uveitis related to a systemic disease, and ten patients (17%) had idiopathic uveitis. There was a decrease in infectious causes over the last decades (p = 0.04) and an increase in idiopathic uveitis (p < 0.01), but the rate of children with posterior uveitis remained constant. There was an overall decrease in the number of children with uveitis referred to Bartiméus. The number of ocular complications at the time of intake was higher in children with acquired disease compared with congenital diseases (p < 0.01), as it was in children with non-infectious uveitis compared with infectious uveitis (p = 0.04). Most comorbidities that were noted were seen in children with infectious uveitis. CONCLUSION: Most patients suffering from visual impairment or blindness due to childhood uveitis had posterior and/or infectious uveitis, mostly congenital. There is a shift in causes which shows a decrease in infectious causes and an increase in idiopathic causes.