Blepharotomy Versus Levator Recession With Adjustable Sutures for Correction of Upper Eyelid Retraction in Thyroid Eye Disease.

PURPOSE: To compare outcome, complications and surgical time of blepharotomy versus levator recession with adjustable sutures (LRWAS) for correction of upper eyelid retraction in thyroid eye disease. METHODS: In the period 2019-2023, we performed a prospective randomized comparative study between blepharotomy and LRWAS. We examined patients, recorded time consumption, and obtained photographs preoperatively, 1 day, 1 week, 3 months, and 6 months after surgery. Outcome was categorized according to Mourits and Sasim`s classification from 1999 (perfect-acceptable-unacceptable). RESULTS: A total of 30 patients (25 women) with a median (range) age of 51.5 (34-74) years at surgery were included. A significant different (p < 0.01) median operation time was found between blepharotomy (41.5 (17-105) minutes) and LRWAS (68 (35-101) minutes). Median time from operation to last examination was 6 (6-18) months. Fifteen patients (24 eyelids) were operated with blepharotomy and 15 patients (25 eyelids) with LRWAS. Preoperative median margin reflex distance 1 was 6.5 (5-8) mm, and at final visit, median margin reflex distance 1 was 3.5 (3-4) mm after blepharotomy and 3.5 (2-5.5) mm after LRWAS. Reoperation was performed in 11 eyelids, 10 due to overcorrection and 1 because of a residual retraction. Significantly more eyelids needed reoperation after LRWAS (n = 9) compared with blepharotomy (n = 2). At final examination, a perfect or acceptable result was found in 14 (93%) patients after both procedures. Significantly shorter total duration of all visits was observed after treatment with blepharotomy (50 (35-70) minutes) compared with LRWAS (65 (40-115) minutes). Wound dehiscence occurred in 1 patient after blepharotomy, and 1 postoperative infection was observed after LRWAS. CONCLUSION: We demonstrate equally high success rates after blepharotomy and LRWAS for correcting upper eyelid retraction in thyroid eye disease, but blepharotomy is less time-consuming and implies fewer reoperations.

Molecular Biomarkers in Thyroid Eye Disease: A Literature Review.

PURPOSE: Thyroid eye disease (TED) is the most common extrathyroidal manifestation of Graves disease. Patients may be severely affected with eyelid retraction, exophthalmos, diplopia, pain, and threatened vision. Autoantibodies against thyroid-stimulating hormone receptor and insulin-like growth factor 1 receptor have shown associations with pathophysiological and clinical traits. Autoantibodies against thyroid-stimulating hormone receptor is in current clinical use as biomarker, but not with unambiguous diagnostic performance. A biomarker with high diagnostic accuracy and/or prognostic capability would be of immense value in diagnosing TED, especially in subclinical cases or when TED precedes the thyroid dysfunction. This article is a literature review on molecular biomarkers of TED. METHODS: A literature search was performed using PubMed and Embase. Studies on molecular biomarkers in blood, tear fluid, and urine were included in the review. RESULTS: Forty-six papers were included, of which 30, 14, and 2 studies on biomarkers in blood, tears, and urine, respectively. Fourteen of the papers evaluated the diagnostic performance of various biomarkers, 12 in blood and 2 in tears. Most studies evaluated single biomarkers, but 3 tested a panel of several markers. Except for autoantibodies against thyroid-stimulating hormone receptor, the reported diagnostic performances for the biomarkers were not confirmed in independent cohorts. In 32 studies, no or insufficient performance data were given, but the findings indicated involvement of various biologic mechanisms in TED including inflammation, oxidative stress, fibrosis, lipid metabolism, and ocular surface microflora. CONCLUSIONS: Currently, serum autoantibodies against thyroid-stimulating hormone receptor is the only molecular biomarker with clinical utility in patients with TED. Several potential biomarkers have been investigated, and particularly panels of multiple biomarkers in tears are promising. To improve patient care, biomarkers in TED should be studied further.

Corneal Vascularization Associated With a Novel PDGFRB Variant.

Purpose: The purpose of this study was to identify the genetic cause of aggressive corneal vascularization in otherwise healthy children in one family. Further, to study molecular consequences associated with the identified variant and implications for possible treatment. Methods: Exome sequencing was performed in affected individuals. HeLa cells were transduced with the identified c.1643C>A, p.(Ser548Tyr) variant in the platelet-derived growth factor receptor beta gene (PDGFRB) or wild-type PDGFRB. ELISA and immunoblot analysis were used to detect the phosphorylation levels of PDGFRß and downstream signaling proteins in untreated and ligand-stimulated cells. Sensitivity to various receptor tyrosine kinase inhibitors (TKIs) was determined. Results: A novel c.1643C>A, p.(Ser548Tyr) PDGFRB variant was found in affected family members. HeLa cells transduced with this variant did not have increased baseline levels of phosphorylated PDGFRß. However, upon stimulation with ligand, excessive activation of PDGFRß was observed compared to cells transduced with the wild-type variant. PDGFRß with the p.(Ser548Tyr) amino acid substitution was successfully inhibited with tyrosine kinase inhibitors (axitinib, dasatinib, imatinib, and sunitinib) in vitro. Conclusions: A novel c.1643C>A, p.(Ser548Tyr) PDGFRB variant was found in family members with isolated corneal vascularization. Cells transduced with the newly identified variant showed increased phosphorylation of PDGFRß upon ligand stimulation. This suggests that PDGF-PDGFRß signaling in these patients leads to overactivation of PDGFRß, which could lead to abnormal wound healing of the cornea. The examined TKIs prevented such overactivation, introducing the possibility for targeted treatment in these patients.

Functional characterization of all-trans retinoic acid-induced differentiation factor (ATRAID).

All-trans retinoic acid-induced differentiation (ATRAID) factor was first identified in HL60 cells. Several mRNA isoforms exist, but the respective proteins have not been fully characterized. In transfected cells expressing Myc-Flag-tagged ATRAID Isoform (Iso) A, B, and C, Iso C was found to be expressed at high levels, Iso A was found to be expressed at low levels due to rapid degradation, and the predicted protein expressed from Iso B was not detected. Iso C was present mainly in an N-glycosylated form. In subcellular fractionation experiments, Iso C localized to the membranous and nuclear fractions, while immunofluorescence analysis revealed that Iso C is located close to the plasma membrane, mainly in cytoplasmic vesicles and in the Golgi area. We confirm that Iso C colocalizes to some extent with endosomal/lysosomal markers LAMP1 and LAMP2. Furthermore, we show that ATRAID co-localizes with RAB11, a GTPase associated with recycling endosomes and implicated in regulating vesicular trafficking.

A Pellino-2 variant is associated with constitutive NLRP3 inflammasome activation in a family with ocular pterygium-digital keloid dysplasia.

Ocular pterygium-digital keloid dysplasia (OPDKD) is a rare hereditary disease characterized by corneal ingrowth of vascularized conjunctival tissue early in life. Later, patients develop keloids on fingers and toes but are otherwise healthy. In a recently described family with OPDKD, we report the presence of a de novo c.770C > T, p.(Thr257Ile) variant in PELI2 in the affected individual. PELI2 encodes for the E3 ubiquitin ligase Pellino-2. In transgenic U87MG cells overexpressing Pellino-2 with the p.(Thr257Ile) amino acid substitution, constitutive activation of the NLRP3 inflammasome was observed. However, the Thr257Ile variant did not affect Pellino-2 intracellular localization, its binding to known interaction partners, nor its stability. Our findings indicate that constitutive autoactivation of the NLRP3 inflammasome contributes to the development of PELI2-associated OPDKD.

Systemic Activation of the Kynurenine Pathway in Graves Disease With and Without Ophthalmopathy.

CONTEXT: Graves disease (GD) is one of the most common autoimmune disorders. Recent literature has shown an immune response involving several different inflammatory related proteins in these patients. OBJECTIVE: This work aimed to characterize the kynurenine pathway, activated during interferon-γ (IFN-γ)-mediated inflammation and cellular (T-helper type 1 [Th1] type) immunity, in GD patients with and without thyroid eye disease (TED). METHODS: We analyzed 34 biomarkers by mass spectrometry in serum samples from 100 patients with GD (36 with TED) and 100 matched healthy controls. The analytes included 10 metabolites and 3 indices from the kynurenine pathway, 6 microbiota-derived metabolites, 10 B-vitamers, and 5 serum proteins reflecting inflammation and kidney function. RESULTS: GD patients showed significantly elevated levels of 7 biomarkers compared with healthy controls (omega squared [ω2] > 0.06; P < .01). Of these 7, the 6 biomarkers with the strongest effect size were all components of the kynurenine pathway. Factor analysis showed that biomarkers related to cellular immunity and the Th1 responses (3-hydroxykynurenine, kynurenine, and quinolinic acid with the highest loading) were most strongly associated with GD. Further, a factor mainly reflecting acute phase response (C-reactive protein and serum amyloid A) showed weaker association with GD by factor analysis. There were no differences in biomarker levels between GD patients with and without TED. CONCLUSION: This study supports activation of IFN-γ inflammation and Th1 cellular immunity in GD, but also a contribution of acute-phase reactants. Our finding of no difference in systemic activation of the kynurenine pathway in GD patients with and without TED implies that the local Th1 immune response in the orbit is not reflected systemically.

Novel inflammatory biomarkers in thyroid eye disease.

Purpose: The aim of this study is to identify biochemical inflammatory markers predicting the presence or risk of developing thyroid eye disease (TED) in patients with Graves' disease (GD). Methods: Patients with GD (n = 100, 77 females) were included from the National Norwegian Registry of Organ-Specific Diseases. Serum samples were analysed for 92 different inflammatory biomarkers using the proximity extension assay. Biomarker levels were compared between groups of patients with and without TED and healthy subjects (HS) (n = 120). Results: TED was found in 36 of 100 GD patients. Significant (P < 0.05) differences in the levels of 52 inflammatory biomarkers were found when GD patients and HS were compared (42 elevated and 10 decreased). Out of the 42 elevated biomarkers, a significantly higher serum level of interleukin-6 (IL6) (P = 0.022) and macrophage colony-stimulating factor (CSF1) (P = 0.015) were found in patients with TED compared to patients without TED. Patients with severe TED also had significantly elevated levels of Fms-related tyrosine kinase 3 ligand (FLT3LG) (P = 0.009). Furthermore, fibroblast growth factor 21 (FGF21) was significantly increased (P = 0.008) in patients with GD who had no signs of TED at baseline but developed TED later. Conclusion: We demonstrate an immunologic fingerprint of GD, as serum levels of several inflammation-related proteins were elevated, while others were decreased. Distinctly increased levels of IL6, CSF1, FLT3LG, and FGF21 were observed in TED, suggesting that these inflammatory proteins could be important in the pathogenesis, and therefore potential new biomarkers for clinical use.

Pellino-2 in nonimmune cells: novel interaction partners and intracellular localization.

Pellino-2 is an E3 ubiquitin ligase that mediates intracellular signaling in innate immune pathways. Most studies of endogenous Pellino-2 have been performed in macrophages, but none in nonimmune cells. Using yeast two-hybrid screening and co-immunoprecipitation, we identified six novel interaction partners of Pellino-2, with various localizations: insulin receptor substrate 1, NIMA-related kinase 9, tumor necrosis factor receptor-associated factor 7, cyclin-F, roundabout homolog 1, and disheveled homolog 2. Pellino-2 showed cytoplasmic localization in a wide range of nonimmune cells under physiological potassium concentrations. Treatment with the potassium ionophore nigericin resulted in nuclear localization of Pellino-2, which was reversed by the potassium channel blocker tetraethylammonium. Live-cell imaging revealed intracellular migration of GFP-tagged Pellino-2. In summary, Pellino-2 interacts with proteins at different cellular locations, taking part in dynamic processes that change its intracellular localization influenced by potassium efflux.

K+ regulates relocation of Pellino-2 to the site of NLRP3 inflammasome activation in macrophages.

Pellino proteins are E3 ubiquitin ligases involved in the innate immune system. Recently, Pellino-2 was reported to modulate the activation of the mouse Nlrp3 inflammasome. We examined the intracellular localization of human Pellino-2 in THP1-derived macrophages during activation with LPS and ATP. We observed that Pellino-2 changed intracellular localization and colocalized with the inflammasome proteins NLRP3 and ASC late in the assembly of the inflammasome. Colocalization with NLRP3 and ASC was also seen in cells maintained in potassium-free medium. The colocalization and inflammasome activation were abrogated by several potassium channel inhibitors, supporting a role for potassium efflux in modulating intracellular localization of Pellino-2. The data suggest that Pellino-2 is essential for mediating the effect of potassium efflux on inflammasome activation.

Temperature-dependent autoactivation associated with clinical variability of PDGFRB Asn666 substitutions.

Ocular pterygium-digital keloid dysplasia (OPDKD) presents in childhood with ingrowth of vascularized connective tissue on the cornea leading to severely reduced vision. Later the patients develop keloids on digits but are otherwise healthy. The overgrowth in OPDKD affects body parts that typically have lower temperature than 37°C. We present evidence that OPDKD is associated with a temperature sensitive, activating substitution, p.(Asn666Tyr), in PDGFRB. Phosphorylation levels of PDGFRB and downstream targets were higher in OPDKD fibroblasts at 37°C but were further greatly increased at the average corneal temperature of 32°C. This suggests that the substitution cause significant constitutive autoactivation mainly at lower temperature. In contrast, a different substitution in the same codon, p.(Asn666Ser), is associated with Penttinen type of premature aging syndrome. This devastating condition is characterized by widespread tissue degeneration, including pronounced chronic ulcers and osteolytic resorption in distal limbs. In Penttinen syndrome fibroblasts, equal and high levels of phosphorylated PDGFRB was present at both 32°C and 37°C. This indicates that this substitution causes severe constitutive autoactivation of PDGFRB regardless of temperature. In line with this, most downstream targets were not affected by lower temperature. However, STAT1, important for tissue wasting, did show further increased phosphorylation at 32°C. Temperature-dependent autoactivation offers an explanation to the strikingly different clinical outcomes of substitutions in the Asn666 codon of PDGFRB.

Clinical features and molecular genetics of patients with ABCA4-retinal dystrophies.

PURPOSE: Pathogenic variations in the ABCA4 gene are a leading cause of vision loss in patients with inherited retinal diseases. ABCA4-retinal dystrophies are clinically heterogeneous, presenting with mild to severe degeneration of the retina. The purpose of this study was to clinically and genetically characterize patients with ABCA4-retinal dystrophies in Norway and describe phenotype-genotype associations. METHODS: ABCA4 variants were detected in 111 patients with inherited retinal disease undergoing diagnostic genetic testing over a period of 12 years. In patients where only a single ABCA4 variant was found, whole-gene ABCA4 sequencing was performed and intronic variants were investigated by mRNA analyses in fibroblasts. Medical journals were used to obtain a clinical description and ultrawidefield autofluorescence images were used to analyse retinal degeneration patterns. RESULTS: The genetic diagnostic yield was 89%. The intronic splice variant c.5461-10T>C was the most prevalent disease-causing variant (27%). Whole-gene ABCA4 sequencing detected two novel intronic variants (c.6729+81G>T and c.6817-679C>A) that we showed affected mRNA splicing. Peripheral retinal degeneration was identified in 33% of patients and was associated with genotypes that included severe loss of function variants. By contrast, peripheral degeneration was not found in patients with a disease duration over 20 years and genotypes including p.(Asn1868lle), c.4253+43G>A or p.(Gly1961Glu) in trans with a loss of function variant. CONCLUSION: This study demonstrates the clinical and genetic heterogeneity of ABCA4-retinal dystrophies in Norway. Further, the study presents novel variants and increases our knowledge on phenotype-genotype associations and the presence of peripheral retinal degeneration in ABCA4-retinal dystrophy patients.

Vision-related quality of life in patients with occipital stroke.

OBJECTIVES: The aim of this study was to detect visual field defects (VFDs) after occipital infarction, investigate the rate of recovery and the impact of VFD upon vision-related quality of life (QoL). MATERIALS AND METHODS: Multicenter, prospective study including patients with MRI verified acute occipital infarction (NOR-OCCIP project). Ophthalmological examination including perimetry was performed within 2 weeks and after 6 months. Vision-related QoL was assessed by the National Eye Institute Visual Function Questionnaire 25 (VFQ-25) at one and 6 months post-stroke. RESULTS: We included 76 patients, reliable perimetry results were obtained in 66 patients (87%) at a median of 8 days after admittance and VFD were found in 52 cases (79%). Evaluation of VFD after 6 months revealed improvement in 52%. Patients with VFD had significantly lower composite score in VFQ-25 at both test points (77 vs 96, P = .001 and 87 vs 97, P = .009), in nine out of eleven subscales of VFQ-25 at 1 month and seven subscales after 6 months, including mental health, dependency, near and distance activities. Milder VFD had better results on VFQ-25 modified composite score (95 vs 74, P = .002).VFD improvement was related to improved VFQ-25 modified composite score (9.6 vs 0.8, P = .018). About 10% of patients with VFD reported driving 1 month post-stroke and 38% after 6 months. CONCLUSION: VFD substantially reduces multiple aspects of vision-related QoL. Severity of VFD is related to QoL and VFD improvement results in better QoL. Neglecting visual impairment after stroke may result in deterioration of rehabilitation efforts. Driving post-stroke deserves particular attention.

Primary Sjögren's syndrome and the eye.

Primary Sjögren syndrome is an autoimmune disease that mainly affects exocrine glands such as the salivary and lacrimal glands. In addition, systemic involvement is common. Primary Sjögren syndrome is of particular interest to ophthalmologists as it constitutes an important differential diagnosis in conditions with dry eye disease. In addition, ocular tests for more precisely diagnosing and monitoring primary Sjögren syndrome have become increasingly important, and new therapeutics for local and systemic treatment evolve as a result of increased understanding of immunological mechanisms and molecular pathways in the pathogenesis of primary Sjögren syndrome. We provide an update of interest to ophthalmologists regarding pathogenesis, diagnosis, investigative procedures, and treatment options.

Absence of the proteoglycan decorin reduces glucose tolerance in overfed male mice.

Studies have implicated the extracellular matrix (ECM) of adipose tissue in insulin resistance. The proteoglycan decorin, a component of ECM, has been associated with glucose tolerance, but possible causal effects on metabolism remain to be explored. We here sought to determine metabolic consequences of loss of decorin in mice (DcnKO). DcnKO mice were fed a low-fat (LF) or high-fat (HF) diet for 10 weeks and body weight and food intake was recorded. An intraperitoneal glucose tolerance test was performed after eight weeks. Blood samples and adipose, liver and muscle tissues were collected at sacrifice. Global gene expression was measured in adipose tissue, and expression of decorin was also analyzed in human adipose samples. DcnKO mice showed increased feed efficiency during overfeeding and impaired glucose tolerance. Adipose leptin mRNA and circulating leptin levels were elevated in DcnKO mice, along with a downregulation of genes involved in ECM organization and triglyceride biosynthesis, and an upregulation of adipose genes involved in complement and coagulation cascades. Consistent with a protective metabolic role for decorin, in obese patients we found increased adipose decorin expression after profound fat loss, particularly in the stromal vascular fraction. Loss of decorin in mice caused impaired glucose tolerance in association with increased feed efficiency and altered gene expression in adipose tissue. Our data provide evidence that decorin is an important factor for maintaining glucose tolerance.

Hyaluronic acid is superior to autologous fat for treatment of temporal hollowing after lateral orbital wall decompression: A prospective interventional trial.

PURPOSE: To compare injections of hyaluronic acid (HA) and autologous fat (AF) for the treatment of unsightly temporal hollowing after lateral orbital wall decompression in thyroid eye disease. METHODS: In this nonblinded prospective comparative interventional study, patients received injections of HA in the right temple and AF in the left temple. Additional injections were given when needed at follow-up after 6, 12, 18, and 24 months. Follow-up included an interview; clinical examination with an evaluation of symmetry, contour, and skin surface; and ultrasound measurements. From photographs, the temporal hollowing was graded 1-3. The main endpoints were grading of temporal hollowing and temporal soft tissue thickness. RESULTS: Seventeen patients were treated bilaterally and 12 unilaterally (five received HA and seven AF). Injection(s) of HA and AF administered at each site were a median (range) of 1 (1-4) and 2 (1-5), respectively. The total combined volume of HA injected per site was 0.9 (0.2-2.0) ml and that of AF was 3.1 (0.5-9.6) ml. At the final examination, a statistically significant difference in mean (SD) grading scores of temporal hollowing due to HA (1.18 (0.26)) compared to those of AF (1.85 (0.44)) was observed (p < 0.001). Six months after administering an injection of HA, the temporal soft tissue thickness was 2.35 (0.24) cm compared to 2.19 (0.28) cm obtained with an injection of AF (p < 0.001). By using a linear mixed-effect model and adjusting for baseline values, age, sex, and refill, the difference in favor of HA persisted at all later follow-ups. Increased fibrosis of the subcutaneous tissue developed at 5/24 sites that received AF. CONCLUSION: Injection of HA is superior to that of AF for treating temporal hollowing after lateral orbital wall decompression.

A tyrosine kinase-activating variant Asn666Ser in PDGFRB causes a progeria-like condition in the severe end of Penttinen syndrome.

Missense variants located to the "molecular brake" in the tyrosine kinase hinge region of platelet-derived growth factor receptor-ß, encoded by PFGFRB, can cause Penttinen-type (Val665Ala) and Penttinen-like (Asn666His) premature ageing syndromes, as well as infantile myofibromatosis (Asn666Lys and Pro660Thr). We have found the same de novo PDGFRB c.1997A>G p.(Asn666Ser) variants in two patients with lipodystrophy, acro-osteolysis and severely reduced vision due to corneal neovascularisation, reminiscent of a severe form of Penttinen syndrome with more pronounced connective tissue destruction. In line with this phenotype, patient skin fibroblasts were prone to apoptosis. Both in patient fibroblasts and stably transduced HeLa and HEK293 cells, autophosphorylation of PDGFRß was observed, as well as increased phosphorylation of downstream signalling proteins such as STAT1, PLCγ1, PTPN11/SHP2-Tyr580 and AKT. Phosphorylation of MAPK3 (ERK1) and PTPN11/SHP2-Tyr542 appeared unaffected. This suggests that this missense change not only weakens tyrosine kinase autoinhibition, but also influences substrate binding, as both PTPN11 tyrosines (Tyr542 and Tyr580) usually are phosphorylated upon PDGFR activation. Imatinib was a strong inhibitor of phosphorylation of all these targets, suggesting an option for precision medicine based treatment.

Recurrent, Activating Variants in the Receptor Tyrosine Kinase DDR2 Cause Warburg-Cinotti Syndrome.

We have investigated a distinct disorder with progressive corneal neovascularization, keloid formation, chronic skin ulcers, wasting of subcutaneous tissue, flexion contractures of the fingers, and acro-osteolysis. In six affected individuals from four families, we found one of two recurrent variants in discoidin domain receptor tyrosine kinase 2 (DDR2): c.1829T>C (p.Leu610Pro) or c.2219A>G (p.Tyr740Cys). DDR2 encodes a collagen-responsive receptor tyrosine kinase that regulates connective-tissue formation. In three of the families, affected individuals comprise singleton adult individuals, and parental samples were not available for verification of the de novo occurrence of the DDR2 variants. In the fourth family, a mother and two of her children were affected, and the c.2219A>G missense variant was proven to be de novo in the mother. Phosphorylation of DDR2 was increased in fibroblasts from affected individuals, suggesting reduced receptor autoinhibition and ligand-independent kinase activation. Evidence for activation of other growth-regulatory signaling pathways was not found. Finally, we found that the protein kinase inhibitor dasatinib prevented DDR2 autophosphorylation in fibroblasts, suggesting an approach to treatment. We propose this progressive, fibrotic condition should be designated as Warburg-Cinotti syndrome.

Iris Malformation and Anterior Segment Dysgenesis in Mice and Humans With a Mutation in PI 3-Kinase.

Purpose: To determine the ocular consequences of a dominant-negative mutation in the p85α subunit of phosphatidylinositol 3-kinase (PIK3R1) using a knock-in mouse model of SHORT syndrome, a syndrome associated with short stature, lipodystrophy, diabetes, and Rieger anomaly in humans. Methods: We investigated knock-in mice heterozygous for the SHORT syndrome mutation changing arginine 649 to tryptophan in p85α (PIK3R1) using physical examination, optical coherence tomography (OCT), tonometry, and histopathologic sections from paraffin-embedded eyes, and compared the findings to similar investigations in two human subjects with SHORT syndrome heterozygous for the same mutation. Results: While overall eye development was normal with clear cornea and lens, normal anterior chamber volume, normal intraocular pressure, and no changes in the retinal structure, OCT images of the knock-in mouse eyes revealed a significant decrease in thickness and width of the iris resulting in increased pupil area and irregularity of shape. Both human subjects had Rieger anomaly with similar defects including thin irides and irregular pupils, as well as a prominent ring of Schwalbe, goniosynechiae, early cataract formation, and glaucoma. Although the two subjects had had diabetes for more than 30 years, there were no signs of diabetic retinopathy. Conclusions: A dominant-negative mutation in the p85α regulatory subunit of PI3K affects development of the iris, and contributes to changes consistent with anterior segment dysgenesis in both humans and mice.

Mutations in MAPKBP1 Cause Juvenile or Late-Onset Cilia-Independent Nephronophthisis.

Nephronophthisis (NPH), an autosomal-recessive tubulointerstitial nephritis, is the most common cause of hereditary end-stage renal disease in the first three decades of life. Since most NPH gene products (NPHP) function at the primary cilium, NPH is classified as a ciliopathy. We identified mutations in a candidate gene in eight individuals from five families presenting late-onset NPH with massive renal fibrosis. This gene encodes MAPKBP1, a poorly characterized scaffolding protein for JNK signaling. Immunofluorescence analyses showed that MAPKBP1 is not present at the primary cilium and that fibroblasts from affected individuals did not display ciliogenesis defects, indicating that MAPKBP1 may represent a new family of NPHP not involved in cilia-associated functions. Instead, MAPKBP1 is recruited to mitotic spindle poles (MSPs) during the early phases of mitosis where it colocalizes with its paralog WDR62, which plays a key role at MSP. Detected mutations compromise recruitment of MAPKBP1 to the MSP and/or its interaction with JNK2 or WDR62. Additionally, we show increased DNA damage response signaling in fibroblasts from affected individuals and upon knockdown of Mapkbp1 in murine cell lines, a phenotype previously associated with NPH. In conclusion, we identified mutations in MAPKBP1 as a genetic cause of juvenile or late-onset and cilia-independent NPH.