Corneal transplantation in Maroteaux-Lamy syndrome

Ocular Manifestations of Hurler-Scheie Syndrome: Recurrence of Host Disease in the Corneal Transplant

Introduction

Hurler-Scheie syndrome is a type of mucopolysaccharidosis I (MPS). In MPS I the decreased activity of alpha-L-iduronidase lysosomal enzyme leads to glycosaminoglycan (GAG) deposition in the intra- and extracellular matrix. Excessive amounts of GAG can accumulate in most layers of the cornea, including epithelial cells, stromal keratocytes, and endothelial cells.

Case Presentation

A 25-year-old female patient suffering from Hurler-Scheie syndrome with multiple ocular manifestations is reported. Due to significant bilateral corneal opacification, penetrating keratoplasty was performed on both eyes. Histopathologic examination of the corneal buttons showed disorganized collagen fibers with heterogenous thickness and many granule-containing keratocytes with excessive cytoplasm. Despite receiving enzyme replacement therapy, in vivo confocal microscopy revealed characteristic vacuoles in the basal epithelium and corneal stroma 96 months after transplantation. High resolution anterior segment optical coherence tomography demonstrated hyperreflective opacities superficial and deeper in the stroma which was consistent with recurrence of host disease in the graft.

Conclusion

To the best of our knowledge, this is the first documented Hurler-Scheie syndrome case of recurrence after penetrating keratoplasty demonstrated by in vivo confocal microscopy. Additionally, this patient manifested severe ocular involvement of MPS which might be an explanation of the progressive course of corneal opacification after transplantation.

Deep Anterior Lamellar Keratoplasty in a Case of Hurler-Scheie Syndrome Undergoing Enzyme Replacement Therapy

PURPOSE

To report successful management of corneal clouding associated with Hurler-Scheie syndrome with deep anterior lamellar keratoplasty (DALK) undergoing concurrent enzyme replacement therapy (ERT).

METHODS

A 13-year-old boy with Hurler-Scheie syndrome (MPS I-HS) presented with corneal clouding in both eyes. He was on ERT with laronidase (Aldurazyme; Genzyme, Cambridge, MA) and had a visual acuity of 20/32 in both eyes. Seven years later, visual acuity in his left eye decreased to counting fingers and DALK was performed for vision recovery. Two years later, visual acuity in his right eye decreased to 20/100 and DALK was performed.

RESULTS

At his last visit, which was 3 years after right eye DALK and 5 years after left eye DALK, the grafts were clear and the corrected visual acuity in his right and left eyes was 20/30 and 20/25, respectively.

CONCLUSIONS

The present case highlights the possible effectiveness of DALK in patients with mucopolysaccharidosis (MPS)-related corneal stromal opacification, treated with ERT.

Outcomes of keratoplasty in the mucopolysaccharidoses: an international perspective

OBJECTIVE

To describe visual outcomes after penetrating keratoplasty and deep anterior lamellar keratoplasty in patients with mucopolysaccharidoses.

METHODS

This is a retrospective review of keratoplasty in consecutive patients from Brazil, England, Finland, Germany, Portugal, Sweden and the USA. All patients had corneal clouding due to mucopolysaccharidoses. Preoperative and postoperative visual outcome and ocular comorbidities were identified. Success was arbitrarily defined as any improvement in visual acuity or best-corrected visual acuity better than logarithm of the minimum angle of resolution 0.30 (20/40). Statistical analysis included only data from first operated eyes in the 16 patients who underwent bilateral keratoplasty.

RESULTS

Forty-eight eyes from 32 patients with mucopolysaccharidoses I, IV or VI are reported. Mean follow-up was 70 months (range: 5-186). Penetrating keratoplasty was performed in 45 eyes and deep anterior lamellar keratoplasty in 3 eyes. At last follow-up, a successful visual outcome for penetrating keratoplasty in first operated/only operated eyes was found in 63%. Rejection episodes occurred in 23% of grafts; however, a clear graft was recorded at last follow-up in 94%. Ocular pathway comorbidities were identified in 63% of eyes transplanted.

CONCLUSIONS

Clear corneal grafts can be obtained for patients with corneal clouding due to mucopolysaccharidosis with improvement in visual acuity in the majority.

Gene Therapy and Gene Editing for the Corneal Dystrophies

Despite ever-increasing understanding of the genetic underpinnings of many corneal dystrophies, gene therapy designed to ameliorate disease has not yet been reported in any human patient. In this review, we explore the likely reasons for this apparent failure of translation. We identify the requirements for success: the genetic defect involved must have been identified and mapped, vision in the affected patient must be significantly impaired or likely to be impaired, no better or equivalently effective treatment must be available, the treatment must be capable of modulating corneal pathology, and delivery of the construct to the appropriate cell must be practicable. We consider which of the corneal dystrophies might be amenable to treatment by genetic manipulations, summarize existing therapeutic options for treatment, and explore gene editing using clustered regularly interspaced short palindromic repeat/Cas and other similar transformative technologies as the way of the future. We then summarize recent laboratory-based advances in gene delivery and the development of in vitro and in vivo models of the corneal dystrophies. Finally, we review recent experimental work that has increased our knowledge of the pathobiology of these conditions.

Spectral domain optical coherence tomography imaging of mucopolysaccharidoses I, II, and VI A

PURPOSE

The purpose of this study was to describe the spectral domain optical coherence tomography (SD-OCT) characteristics of patients with retinal manifestations of mucopolysaccharidoses (MPSs) I, II, and IV A.

DESIGN

The research was a prospective, observational study.

METHODS

Fourteen consecutive patients with variants of MPS and 15 healthy subjects underwent ophthalmic assessments including fundus examinations and SD-OCT.

RESULTS

The fundus examinations revealed that four patients (two MPS I and two MPS II) had pigmented retinopathy in both eyes. In addition, one MPS II patient had cystoid macular edema and two MPS II patients had abnormal disc morphology. SD-OCT revealed thinning of the parafoveal photoreceptor inner segment/outer segment (IS/OS; two MPS I and one MPS II) and perifoveal photoreceptor IS/OS (two MPS I and five MPS II). All MPS I and II patients exhibited thickening of the central foveal external limiting membrane (ELM). Fundus and SD-OCT findings were normal in MPS IV A and healthy subjects. The foveal ELM was significantly thicker in MPS I and II patients than in healthy subjects (P =0 .000 and P =0 .000, respectively). The foveal IS/OS was significantly thinner in MPS I, II, and IV A patients than in healthy subjects (P = 0.000, P = 0.000, and P = 0.030, respectively). The foveal retinal pigment epithelium layer was also thinner in MPS II patients than in healthy subjects (P = 0.007) CONCLUSIONS: In MPS, accumulation of glycosaminoglycans in retinal tissue induced retinal degeneration and pigmentary retinopathy. SD-OCT was a useful tool for detecting retinal pathology, particularly changes in ELM and IS/OS.

Indications for and outcomes of deep anterior lamellar keratoplasty in mucopolysaccharidoses

PURPOSE

To describe the outcome of deep anterior lamellar keratoplasty (DALK) for visually significant corneal clouding in patients with mucopolysaccharidoses (MPS).

METHODS

A retrospective consecutive case series of patients with MPS and corneal clouding were analyzed at a tertiary eye hospital. A review of the English literature regarding MPS and DALK was performed. The main outcomes measures of the study were intraoperative surgical complications, change in visual acuity, and postoperative DALK-related complications.

RESULTS

Four eyes from 2 patients with MPS I (Hurler's syndrome and Hurler-Scheie syndrome) and a history of DALK met inclusion criteria for the case series. Using the "big-bubble" technique, DALK was performed successfully in all eyes. Completed Descemet's membrane baring was achieved in 3 or 4 eyes and a pre-Descemet's membrane dissection in 1 eye. The mean age at the time of DALK was 17.3 years (range: 15.4 to 19.5 years). Mean follow-up time after DALK was 16.7 months (range: 6 to 31 months). Mean visual acuity before DALK was 20/80 (0.59 ± 0.12 logMAR). Mean visual acuity at the last visit for all 4 eyes was 20/50 (0.41 ± 0.17 logMAR). Visual acuity improved in all eyes. Recurrence of MPS corneal clouding was not noted in any of the corneal grafts.

CONCLUSIONS

DALK is a beneficial and preferable intervention in appropriate patients with significant corneal clouding due to MPS I. Improvement in vision can be obtained with stable, clear corneal grafts, although other ophthalmic manifestations may limit vision.

Gene therapy for diseases of the cornea - a review

The cornea is particularly suited to gene therapy. The cornea is readily accessible, normally transparent, and is somewhat sequestrated from the general circulation and the systemic immune system. The principle of genetic therapy for the cornea is to use an appropriate vector system to transfer a gene to the cornea itself, or to the ocular environs, or systemically, so that a transgenic protein will be expressed that will modulate congenital or acquired disease. The protein may be structural such as a collagen, or functionally active such as an enzyme, cytokine or growth factor that may modulate a pathological process. Alternatively, gene expression may be silenced by the use of modalities such as antisense oligonucleotides. Interestingly, despite a very considerable amount of work in animal models, clinical translation directed to gene therapy of the human cornea has been minimal. This is in contrast to gene therapy for monogenic inherited diseases of the retina, where promising early results of clinical trials for Leber's congenital amaurosis have already been published and a number of other trials are ongoing.

Does enzyme replacement therapy influence the ocular changes in type VI mucopolysaccharidosis?

BACKGROUND

To describe the ocular changes noted in seven patients with type VI mucopolysaccharidosis (MPS VI) during 44 months of follow-up while on enzyme replacement therapy (ERT).

METHODS

One male and six female patients with MPS VI were followed-up for a mean period of 44 months while undergoing enzyme replacement therapy (ERT) with recombinant arylsulfatase B (Naglazyme). They were examined annually for visual acuity, corneal clouding, intraocular pressure (IOP), optic nerve head and fundus morphology. Corneal clouding was documented by photography. We acknowledge that our methodology may not have been sensitive enough to detect extremely mild ocular changes, including minimal increases in corneal thickness or clouding. Nevertheless, this limitation has been considered in the interpretation of our findings.

RESULTS

Ophthalmological findings remained stable in 5/7 patients. One patient experienced a modest improvement in visual acuity of more than 2 Snellen lines in one eye, while another patient suffered a deterioration in visual acuity of more than 2 Snellen lines in both eyes. Five out of seven patients showed optic nerve pathology: two of these exhibited optic nerve head swelling, while the other three showed variable degrees of optic nerve atrophy. All seven patients suffered from the typical corneal stromal opacities, however, to variable extents.

CONCLUSION

Visual function and ocular findings did not deteriorate in six out of seven MPS VI patients during a mean follow-up period of 3 and a half years on ERT.

Mucopolysaccharidoses and the eye

The mucopolysaccharidoses (MPSs) are a group of disorders caused by inherited defects in lysosomal enzymes resulting in widespread intra- and extra-cellular accumulation of glycosaminoglycans. They have been subdivided according to enzyme defect and systemic manifestations and include MPS IH (Hurler), MPS IS (Scheie), MPS IH/S (Hurler/Sheie), MPS II (Hunter), MPS III (Sanfilippo), MPS IV (Morquio), MPS VI (Maroteaux-Lamy), MPS VII (Sly) and MPS IX (Natowicz). The mucopolysaccharidoses have a spectrum of systemic manifestations, including airway and respiratory compromise, skeletal deformities, intellectual and neurological impairment, cardiac abnormalities, and gastrointestinal problems. Ocular manifestations are common in the mucopolysaccharidoses and may result in significant visual impairment. Corneal opacification of varying severity is frequently seen, as well as retinopathy, optic nerve swelling and atrophy, ocular hypertension, and glaucoma. New treatment modalities for the systemic manifestations of the mucopolysaccharidoses include bone marrow transplant and enzyme replacement therapy, and have resulted in an improved prognosis in many cases. This article reviews the systemic and ocular manifestations of the mucopolysaccharidoses, as well as new treatment options, and discusses the ophthalmic management of mucopolysaccharidosis patients.

Congenital Corneal Opacities in a Cornea Referral Practice

PURPOSE

To address the primary causes of the congenital corneal opacities seen on the Cornea Service at Wills Eye Hospital (Philadelphia, PA), the associated systemic anomalies and their management.

METHODS

Retrospective review of the medical records of all patients with the diagnosis of congenital corneal opacities seen at the Cornea Service from January 1, 1992 to June 30, 2003. Children 12 years old or younger at the first visit to our department were included in the study. We classified the location and extent of corneal pathology. We divided the management into medical and surgical.

RESULTS

Seventy-two eyes of 47 patients were included in the study. The mean follow-up time from the first to the last visit was 33.1 months. The most common primary cause of congenital corneal abnormalities was Peters anomaly (40.3%), followed by sclerocornea (18.1%), dermoid (15.3%), congenital glaucoma (6.9%), microphthalmia (4.2%), birth trauma, and metabolic disease (2.8%). Seven eyes (9.7%) were classified as idiopathic. Ten patients had systemic abnormalities associated with their ocular condition. The management was medical in 38 eyes (52.7%). Twenty-four eyes (32.4%) underwent only 1 penetrating keratoplasty (PK). Only 1 eye received a regraft during the follow-up period. Eight grafts failed during the follow-up period.

CONCLUSION

The importance of this study is to share our experience with this rare entity, congenital corneal opacities, describing their clinical presentation and their management.

Adenovirus-mediated gene therapy for corneal clouding in mice with mucopolysaccharidosis type VII

Recent advances in systemic treatments for mucopolysaccharidosis have led to therapies that improve the multiple somatic features of this disease, but the therapeutic effect on ocular manifestations such as corneal clouding is not satisfactory. Here, we administered an adenovirus expressing human beta-glucuronidase (AxCAhGUS) into the anterior chamber or intrastromal region of the cornea in mice with mucopolysaccharidosis type VII (B6/MPSVII), and successfully treated corneal clouding of MPSVII. When we injected AxCAhGUS into the anterior chamber of the eyes, cells expressing beta-glucuronidase (GUSB) were located mainly in the trabecular meshwork as well as in all corneal regions, and subsequent pathological corrections in the cornea were achieved. Widespread transgene expression was also observed when we administered AxCAhGUS inside the cornea after lamellar keratotomy, and rapid elimination of the lysosomal storage in the corneal keratocytes occurred. Furthermore, intrastromal vector administration did not generate significant levels of anti-adenovirus neutralizing antibodies, and secondary vector administration was effective. Based on these observations, we conclude that it is worth developing a treatment strategy for corneal clouding in mucopolysaccharidosis based on direct intraocular administration of adenoviral vectors.