Ocular abnormalities in neurofibromatosis 2

K, Baral A. Bilateral vestibular schwannoma with a cooccurring meningioma in a child: a case report and review of literature

Introduction

Meningioma and vestibular schwannoma (VS) are the first and second most common benign central nervous system tumors. The coexistence of VS and meningioma presents a rare clinical scenario, particularly in pediatric patients. This report presents a case of bilateral VS with a cooccurring meningioma in a Nepali child and provides an overview of the literature on this condition.

Case report

A 15-year-old male presented with bilateral sensorineural hearing loss, seizures, and neurological deficits and was ultimately diagnosed with concomitant bilateral acoustic neuroma and meningioma. The patient underwent radiosurgery for bilateral VS and nonoperative management of the meningioma. Long-term follow-up revealed symptomatic improvement, emphasizing the importance of a multidisciplinary approach in managing such complex cases. The management of these tumors requires tailored treatment strategies guided by tumor characteristics and associated risks.

Discussion

Meningioma and VS are common tumors of the central nervous system. Their coexistence is possible in neurofibromatosis type 2 but is exceedingly rare in pediatric age group. The tumors, often coexisting, pose diagnostic challenges. Diagnosis relies on clinical and genetic features, with multidisciplinary management involving various specialists. Treatment aims to preserve function and quality of life, utilizing approaches such as bevacizumab and surgical intervention. The role of radiation therapy remains uncertain. Genetic testing and regular monitoring are vital for early detection and intervention.

Conclusion

The cooccurrence of acoustic neuromas and meningiomas is poorly understood, with limited reported cases and unclear pathophysiological mechanisms. Further research into the genetic and molecular mechanisms underlying the coexistence of these tumors is needed to optimize patient outcomes in this rare clinical entity.

Gene Therapy for Neurofibromatosis Type 2-Related Schwannomatosis: Recent Progress, Challenges, and Future Directions

Neurofibromatosis type 2 (NF2)-related schwannomatosis is a rare autosomal dominant monogenic disorder caused by mutations in the NF2 gene. The hallmarks of NF2-related schwannomatosis are bilateral vestibular schwannomas (VS). The current treatment options for NF2-related schwannomatosis, such as observation with serial imaging, surgery, radiotherapy, and pharmacotherapies, have shown limited effectiveness and serious complications. Therefore, there is a critical demand for novel effective treatments. Gene therapy, which has made significant advancements in treating genetic diseases, holds promise for the treatment of this disease. This review covers the genetic pathogenesis of NF2-related schwannomatosis, the latest progress in gene therapy strategies, current challenges, and future directions of gene therapy for NF2-related schwannomatosis.

Structural Abnormalities of the Central Retina in Neurofibromatosis Type 2

INTRODUCTION

This case-control study seeks to systematically characterize the central retinal findings in a large cohort of patients with neurofibromatosis type 2 (NF2) using spectral domain optical coherence tomography (SD-OCT) as well as the examination of the potential use of this technique as a diagnostic tool in NF2.

METHODS

Fifty-four patients with an NF2 diagnosis seen in a quaternary national service were age- and gender-matched to 55 controls from the normal population. Two masked assessors categorized SD-OCT images using predefined abnormalities: retinal tufts, epiretinal membrane (ERM) appearance, retinal hamartoma, and foveal contour. Specificity, sensitivity, and positive and negative predictive values were calculated for each retinal abnormality. Trends of retinal abnormalities with NF2 genetic severity groups (1. tissue mosaic; 2A. mild classic; 2B. moderate classic; and 3. severe) were investigated.

RESULTS

We found retinal abnormalities in 26 patients with NF2 (48%) and 2 control patients (4%); retinal tufts were the most common abnormality therein (43%) and were not seen in controls. The specificity and sensitivity of the graded abnormalities on OCT scans in NF2 were 96% and 48%, respectively, with a positive predictive value of 93%. In our cohort, retinal tufts had a specificity of 100%, a sensitivity of 43%, and a positive predictive value of 100%. Retinal hamartomas were seen only in NF2 patients (35% sensitivity and 100% specificity). ERMs had 96% specificity and 13% sensitivity. The proportion of patients with retinal abnormalities increased statistically significantly with NF2 genetic severity; all patients within the 3. severe genetic severity had an abnormal SD-OCT.

DISCUSSION/CONCLUSION

We present a systematic study of central retinal abnormalities in an NF2 population as seen on SD-OCT imaging. Our results show a high frequency of retinal abnormalities that are readily detected by SD-OCT imaging. The presence of retinal tufts may be a novel marker of NF2 with both high specificity and a positive predictive value for NF2, compared to other well-known ocular features of NF2, and may have a place in the NF2 diagnostic criteria.

The Role of Neuro-Ophthalmologists in the Care of Patients With Neurofibromatosis Type 2

Neurofibromatosis type 2 (NF2) is a rare genetic disorder, affecting the central nervous system and leading to various degrees of disability. Its hallmark is bilateral vestibular schwannomas that invariably lead to progressive hearing loss. Specific ophthalmic abnormalities in patients with NF2 may help to establish an early diagnosis. These include juvenile cataract, epiretinal membrane, combined hamartoma of the retina and the retinal pigment epithelium, optic disc glioma, and optic nerve sheath meningioma. In addition, intracranial tumors may produce a variety of neuro-ophthalmic abnormalities that have the potential to impair visual function, such as postpapilledema optic atrophy, compression of the visual pathways, keratopathy, ocular motor cranial nerve palsies, and amblyopia. Care of NF2 patients is best provided by interdisciplinary medical teams including a neuro-ophthalmologist.

Magnetic resonance imaging (MRI) features of cataracts in pediatric and young adult patients

Background

The goal of this study is to systematically evaluate the magnetic resonance imaging (MRI) signal characteristics and size of cataracts that may be encountered in pediatric and young adult patients.

Methods

A retrospective analysis of the MRI features with cataracts in a series of cases, including characterization of signal intensity on T2-weighted and T1-weighted sequences, as well as measuring the thickness of the lens.

Results

Among nine cataracts in seven patients, three lenses were thickened and hyperintense on T2-weighted sequences, presumably related to osmotic effects. The rest of the lenses were either normal in size and signal characteristics, such as in the cases of neurofibromatosis type 2 or small in cases of microphthalmos, with signal characteristics related to calcifications.

Conclusions

There are several different types of cataracts that can occur in pediatric and young adult patients, which may or may not be conspicuous on MRI. The findings in this study can serve as a guide for what abnormalities of the lens may be encountered on MRI.

A CASE OF NEUROFIBROMATOSIS TYPE 2 WITH UNUSUAL CLINICAL FEATURES

PURPOSE

To report a case of a neurofibromatosis Type 2 with unusual clinical features.

METHODS

Observational clinical case report.

RESULTS

A 22-year-old woman was referred with bilateral blurred vision and macular "scars." Ocular examination revealed bilateral posterior subcapsular and cortical cataract, optic disk swelling, hyperpigmented macular lesions, epiretinal membrane, and macular temporal dragging. Spectral-domain optical coherence tomographic imaging showed bilateral epiretinal membranes, peripapillary nerve fiber layer thickening, and vitreoretinal tractional bands. In the right eye, focal choroidal excavation was noted at the site of the macular lesion. In fluorescein angiography, mild vascular leakage, capillary nonperfusion, and ground glass hyperfluorescence was seen in temporal periphery of the right eye. Brain imaging showed intracranial calcification and vestibular schwannoma, which was removed by a neurosurgeon. A clinical diagnosis of neurofibromatosis Type 2 was made.

CONCLUSION

A case of neurofibromatosis Type 2 with some possibly novel or rare findings, namely, focal choroidal excavation, ash leaf spots, and intracranial calcifications was presented.

Successful surgical management of bilateral epiretinal membrane in a child with only café-au-lait spots

A 6-year-old boy diagnosed as anisometropic amblyopia, with only café-au-lait spots and a family history of neurofibromatosis, presented with decrease in vision in the both eyes. Dilated fundus examination showed epiretinal membrane in both eyes over the macula. He underwent successful surgical management of the epiretinal membrane.

The molecular pathogenesis of schwannomatosis, a paradigm for the co-involvement of multiple tumour suppressor genes in tumorigenesis

Schwannomatosis is characterized by the predisposition to develop multiple schwannomas and, less commonly, meningiomas. Despite the clinical overlap with neurofibromatosis type 2 (NF2), schwannomatosis is not caused by germline NF2 gene mutations. Instead, germline mutations of either the SMARCB1 or LZTR1 tumour suppressor genes have been identified in 86% of familial and 40% of sporadic schwannomatosis patients. In contrast to patients with rhabdoid tumours, which are due to complete loss-of-function SMARCB1 mutations, individuals with schwannomatosis harbour predominantly hypomorphic SMARCB1 mutations which give rise to the synthesis of mutant proteins with residual function that do not cause rhabdoid tumours. Although biallelic mutations of SMARCB1 or LZTR1 have been detected in the tumours of patients with schwannomatosis, the classical two-hit model of tumorigenesis is insufficient to account for schwannoma growth, since NF2 is also frequently inactivated in these tumours. Consequently, tumorigenesis in schwannomatosis must involve the mutation of at least two different tumour suppressor genes, an occurrence frequently mediated by loss of heterozygosity of large parts of chromosome 22q harbouring not only SMARCB1 and LZTR1 but also NF2. Thus, schwannomatosis is paradigmatic for a tumour predisposition syndrome caused by the concomitant mutational inactivation of two or more tumour suppressor genes. This review provides an overview of current models of tumorigenesis and mutational patterns underlying schwannomatosis that will ultimately help to explain the complex clinical presentation of this rare disease.

Diagnosis, Management, and New Therapeutic Options in Childhood Neurofibromatosis Type 2 and Related Forms

Neurofibromatosis type 2 (NF2; MIM # 101000) is an autosomal dominant disorder characterized by the development of vestibular schwannomas (VSs); schwannomas of other cranial, spinal, and cutaneous nerves; cranial and spinal meningiomas or other central nervous system tumors (eg, ependymomas and astrocytomas) or both. Additional features include eye (eg, early onset cataracts, optic nerve sheath meningiomas, retinal or pigment epithelial hamartomas or both, and epithelial retinal membranes) and skin abnormalities (eg, flat dermal [NF2 plaques] or spherical subcutaneous nodular schwannomas or both, and few, atypical café-au-lait spots). Clinically, children with NF2 fall into 2 main groups: (1) congenital NF2 with bilateral VSs detected as early as the first days to months of life, which can be stable or asymptomatic for 1-2 decades and suddenly progress; and (2) severe prepubertal (Wishart type) NF2 with multiple (and rapidly progressive) central nervous system tumors other-than-VS, which usually presents first, years before VSs, both associated with more marked skin and eye involvement (vs the classical mild adult [Gardner type] NF2, with bilateral VSs presenting in young adulthood, sometimes as the only disease feature). Individuals manifesting unilateral VS associated with ipsilateral meningiomas or multiple schwannomas localized to a part of the peripheral nervous system have mosaic or segmental NF2; individuals developing multiple nonVS, nonintradermal cranial, spinal, and peripheral schwannomas (histologically proven) have schwannomatosis (SWNTS). NF2 is caused by mutations in the NF2 gene at chromosome 22q12.1, which encodes for a protein called merlin or schwannomin, most similar to the exrin-readixin-moesin proteins; mosaic or segmental NF2 is because of mosaic phenomena for the NF2 gene, whereas SWNTS is caused by germline and possibly mosaic mutations either in the SMARCB1 gene (SWNTS1; MIM # 162091) or the LZTR1 gene (SWNTS2; MIM # 615670), both falling within the 22q region. Data driven from in vitro and animal studies on the merlin pathway allowed biologically targeted treatment strategies (employing Lapatinib, Erlotinib, Everolimus, Picropodophyllin, OSU.03012, Imatinib, Sorafenib, and Bevacizumab) aimed at multiple tumor shrinkage or regression or both and tumor arrest of progression with functional improvement.

Extracranial orbital meningioma extending into the nasosinus in neurofibromatosis type 2

PURPOSE

The purpose of this study was to report a rare case of neurofibromatosis type 2 (NF2) with extracranial orbital meningioma extending into the frontal and ethmoidal sinuses.

METHODS

This is clinical report of a 17-year-old male patient with NF2. Results of an ocular examination, computed tomography scan, and pathological findings of space-occupied orbital and nasosinus lesions are presented.

RESULTS

Computed tomography scan revealed a high-density soft tissue mass occupying the right superionasal orbit extending into the frontal and ethmoidal sinuses and bilateral acoustic schwannomas in the brain. Biopsy of the right orbital lesion demonstrated a typical meningioma as indicated with routine hematoxylin-eosin staining and immunohistochemical evaluation.

CONCLUSIONS

In this patient, an extracranial orbital meningioma, rather than optic nerve sheath meningioma extending into nasosinus, designates a diagnosis of NF2. Ophthalmologists should be aware of the possibility that patients with an extracranial orbital meningioma may also have NF2.

[Type 2 neurofibromatosis: intergenerational differences in genetic and clinical expression]

INTRODUCTION

Neurofibromatosis type 2 (NF2) is a rare dominantly inherited disease. Its clinical presentation can be completely different in children and adults and early diagnosis is often difficult. The NF2 gene molecular analysis can help for diagnosis, but its result can be negative in case of NF2 mosaicism.

OBSERVATIONS

We report the case of a 43-year-old man who had developed a severe phenotype with bilateral vestibular schwannomas at 19 years of age. His son presented a retinal hamartoma with loss of vision in his right eye at 2 months of age. At 9 years of age, asymptomatic schwannomas of the cranial nerves were discovered: cranial nerves X (left), XI (left), and VIII (bilateral). Partial constitutional NF2 deletion (from exons 2-7) was detected in his son. The deletion was not detectable in the DNA blood of his father and we strongly suspect a mosaic form of NF2.

CONCLUSION

Ophthalmological manifestations can be the initial sign of NF2 in childhood. These features must be actively sought during the first year of life in individuals at risk of NF2. NF2 mosaicism is often described as a mild form of NF2 with a very low risk of transmission to the carrier's children. We show that NF2 mosaicism can sometimes develop severe NF2 symptoms and we confirm that the transmission risk to the offspring depends on the proportion of zygotes carrying the mutation. NF2 remains a life-limiting and life-spoiling condition. Early diagnosis is necessary to prevent complications and the follow-up of NF2 patients must be organized throughout life in specialty centers.

Astrocytic hamartoma of the optic disc and multiple café-au-lait macules in a child with neurofibromatosis type 2

Neurofibromatosis type 2 (NF2) is a heritable syndrome characterized by multifocal proliferation of neural crest-derived cells. The characteristic and diagnostic finding of NF2 is bilateral vestibular nerve schwannomas (acoustic neuromas). In addition to other tumors involving the central and peripheral nervous systems, ophthalmic manifestations, including posterior subcapsular and peripheral cortical cataracts, optic nerve meningiomas, epiretinal membrane, and combined pigment epithelial and retinal hamartomas, are common to NF2. Herein we present an 8-year-old girl with NF2 and astrocytic hamartoma of the optic disc. This patient had been previously diagnosed with NF1 on the basis of multiple CAL macules and suspected subcutaneous neurofibromas. However, neuroimaging revealed bilateral acoustic neuromas, leading to a clinical diagnosis of NF2. Subsequent molecular genetic analysis confirmed the NF2 diagnosis. Multiple CAL macules and astrocytic hamartomas, while associated with NF1, are rarely associated with NF2. Specifically, we are not aware of any reported cases of optic disc astrocytic hamartoma in the setting of NF2.

Retinal disorders

The retina represents part of the central nervous system (CNS). After modifying the neural signal, the axon of the last neuron enters the optic nerve and leaves the eye. In most cases of retinal disease leading to visual loss, the diagnosis will be made by an ophthalmologist after examining the ocular fundus. Some retinal disorders, however, might not be detectable at the time of examination. Those patients will be referred to a neurologist for "unexplained visual loss" when suspecting a lesion behind the optic nerve. Moreover, knowledge of potential retinal abnormalities is useful for the neurologist when seeing patients with CNS disease, which can manifest itself also in the retina. This chapter aims to give an overview about retinal disorders causing no or only few retinal abnormalities, those associated with neurological diseases, as well as the most important retinal diseases involving the tissues of the ocular fundus (vitreous body, retina, pigment epithelium, and the choroid). The most frequently used examination techniques and diagnostic tools are described. Tumors, vascular disease, especially diabetic retinopathy, age-related macular degeneration, chorioretinal inflammatory and toxic disorders, paraneoplastic retinopathies, inherited retinal dystrophies, and retinal involvement in CNS disease such as phakomatoses and multiple sclerosis are discussed.

Neurofibromatosis 2 [Bilateral acoustic neurofibromatosis, central neurofibromatosis, NF2, neurofibromatosis type II]

Neurofibromatosis 2 is a dominantly inherited tumor predisposition syndrome caused by mutations in the NF2 gene on chromosome 22. Affected individuals inevitably develop schwannomas typically affecting both vestibular nerves leading to deafness. Rehabilitation with brainstem implants is improving this outcome. Schwannomas also occur on other cranial nerves, on spinal nerve roots, and on peripheral nerves. Meningiomas and ependymomas are other tumor features. In excess of 50% of patients represent new mutations and as many as one third are mosaic for the underlying disease causing mutation. Although truncating mutations (nonsense and frameshifts) are the most frequent germline event and cause the most severe disease, single and multiple exon deletions are common. A strategy for detection of the latter is vital for a sensitive analysis. NF2 represents a difficult management problem with most patients facing substantial morbidity and reduced life expectancy. Surgery remains the focus of current management, although watchful waiting and occasionally radiation treatment have a role. In the future, the development of tailored drug therapies aimed at the genetic level are likely to provide huge improvements for this devastating, life limiting condition.

Neurofibromatosis type II presenting as vertical diplopia

Neurofibromatosis type II (NF II) is rare and most commonly presents with hearing loss, tinnitus and/or vestibular disturbance in the third decade of life. The authors describe a rare case presenting with NF II with vertical diplopia due to IV(th) nerve palsy. The patient was otherwise asymptomatic despite multiple extensive lesions on MRI.

Management of the patient and family with neurofibromatosis 2: a consensus conference statement

A consensus conference on neurofibromatosis 2 (NF2) was held in 2002 at the request of the United Kingdom (UK) Neurofibromatosis Association, with particular emphasis on vestibular schwannoma (VS) surgery. NF2 patients should be managed at specialty treatment centres, whose staff has extensive experience with the disease. All NF2 patients and their families should have access to genetic testing because presymptomatic diagnosis improves the clinical management of the disease. Some clinical manifestations of NF2, such as ocular abnormalities, can be detected in infancy; therefore, clinical screening for at-risk members of NF2 families can start at birth, with the first magnetic resonance (MRI) scan at 10-12 years of age. Minimal interference, maintenance of quality of life, and conservation of function or auditory rehabilitation are the cornerstones of NF2 management, and the decision points to achieve these goals for patients with different clinical presentations are discussed.

Neurofibromatosis type 2

Neurofibromatosis type 2 is an autosomal-dominant multiple neoplasia syndrome that results from mutations in the NF2 tumour suppressor gene located on chromosome 22q. It has a frequency of one in 25,000 livebirths and nearly 100% penetrance by 60 years of age. Half of patients inherit a germline mutation from an affected parent and the remainder acquire a de novo mutation for neurofibromatosis type 2. Patients develop nervous system tumours (schwannomas, meningiomas, ependymomas, astrocytomas, and neurofibromas), peripheral neuropathy, ophthalmological lesions (cataracts, epiretinal membranes, and retinal hamartomas), and cutaneous lesions (skin tumours). Optimum treatment is multidisciplinary because of the complexities associated with management of the multiple, progressive, and protean lesions associated with the disorder. We review the molecular pathogenesis, genetics, clinical findings, and management strategies for neurofibromatosis type 2.

Neurofibromatosis type 2: optic nerve sheath meningioma in one orbit, intramuscular schwannoma in the other

A highly unusual patient with neurofibromatosis type 2 (NF2) presenting with simultaneous bilateral orbital tumors is described. A 12-year-old girl with a family history of NF2 was examined because of bilateral proptosis. Visual acuities were light perception RE and 20/40 LE. Magnetic resonance imaging studies showed bilateral cerebellopontine angle tumors, a tumor surrounding the right intraorbital optic nerve, and a large left lateral orbital mass mixed with the lateral rectus muscle. The histopathological diagnoses following incisional biopsies were right optic nerve sheath meningioma and left intramuscular schwannoma. The left-sided orbital schwannoma and the right-sided vestibular schwannoma were treated with fractionated stereotactic radiotherapy. This patient enlarges the spectrum of clinical presentations that can be encountered at young age in patients with NF2.

Neurofibromatosis 2 leads to higher incidence of strabismological and neuro-ophthalmological disorders

PURPOSE

Ophthalmic features of neurofibromatosis 2 (NF2) include juvenile cataract, retinal hamartomas and tumours of the cranial nerves. We hypothesize that these tumours lead to strabismological and neuro-ophthalmological symptoms, including palsies of cranial nerves III, IV and VI, nystagmus and gaze palsies.

METHODS

We carried out a retrospective review of 73 patients with known genotype. They underwent ophthalmic, neuro-ophthalmological and strabismological examination. Statistical analysis was performed by calculating odds ratios and their 95% confidence intervals.

RESULTS

Mean best corrected visual acuity was 0.85. Strabismus was found in 38 of 73 patients (52%). A deviation based on a cranial nerve palsy was found in 16 patients (22%) and three had supranuclear palsies. Eleven of 73 patients had a nystagmus, mostly caused by peripheral-vestibular disturbance. Binocular single vision was normal in 41 (58%), subnormal in six (8%) and not present in 24 (34%) patients. The average refractive error was - 0.57 D. Myopia of >or= 0.5 D was present in 47 (33%) eyes and hyperopia of >or= 2.0 D was measured in 11 (8%) eyes. In the subgroup analysis of NF2 mutation types, the relative risk for cranial nerve palsies and negative stereopsis was statistically significantly increased for the nonsense mutation group. The mosaicism group had a statistically significant decreased relative risk for concomitant squint, as did patients with unfound mutations for strabismus and poor stereopsis.

CONCLUSIONS

The present study is, to our knowledge, the first to examine a larger collection of NF2 patients for strabismological and neuro-ophthalmological lesions. Compared with the normal population, our sample showed a higher amount of strabismus, refractive errors and an increased incidence of vestibular nystagmus.

Forensic considerations in cases of neurofibromatosis--an overview

Neurofibromatosis types 1 and 2 are inherited neurocutaneous disorders characterized by a variety of manifestations that involve the circulatory system, the central and peripheral nervous systems, the skin, and the skeleton. Significant reduction in lifespan occurs in both conditions often related to complications of malignancy and hypertension. Individuals with these conditions may also be the subject of medicolegal autopsy investigation if sudden death occurs. Unexpected lethal events may be associated with intracranial neoplasia and hemorrhage or brainstem compression. Vasculopathy with fibrointimal proliferation may result in critical reduction in blood flow within the coronary or cerebral circulations, and aneurysmal dilatation may be associated with rupture and life-threatening hemorrhage. An autopsy approach to potential cases should include review of the history/hospital record, liaison with a clinical geneticist (to include family follow-up), a full external examination with careful documentation of skin lesions and nodules, measurement of the head circumference in children, photography, possible radiologic examination, a standard internal autopsy examination, documentation of the effects of previous surgery and/or chemo/radiotherapy, examination for specific tumors, specific examination and sampling of vasculature (renal, cerebral, and cardiac), formal neuropathologic examination of brain and spinal cord, possible examination of the eyeballs, examination of the gastrointestinal tract, histology to include tumors, vessels, gut, and bone marrow, toxicological testing for anticonvulsants, and sampling of blood and tissue for possible cytogenetic/molecular evaluation if required.

Neurofibromatosis 2 leads to choroidal hyperfluorescence in fluorescein angiography

BACKGROUND

For the diagnosis of NF 2, ocular findings like juvenile cataract, retinal and combined hamartomas of the retinal pigment epithelium and the retina as well as tumours of the optic nerve play an important role. An early diagnosis is essential in order to inhibit deafness from bilateral vestibular schwannoma. But sometimes the Manchester diagnostic criteria for NF2 are not completely fulfilled. Frequently, suspicious macular anatomy is found in neurofibromatosis 2 (NF2) patients. We hypothesise that the underlying retinal pigment epithelium or the retina of the macular region alters in NF2 patients. Therefore, we have tested by fluorescence angiography whether NF2 is associated with chorioretinal changes.

METHODS AND PATIENTS

In a prospective study, 48 patients matching the criteria for NF2 with known genotype underwent a complete ophthalmic examination including funduscopy and fluorescence angiography. The influence of the genotype was statistically analysed by odds ratios and their 95% confidence intervals.

RESULTS

Eleven eyes of nine patients showed choroidal hyperfluorescence in the macular region on fluorescence angiography. There was staining spreading from grainy hyperfluorescence to minor variants of a combined hamartoma of the retina and the retinal pigment epithelium. All of these manifestations presented without leakage in the late angiographic phases. These choroidal findings were present in one patient with frameshift mutation, in two patients with nonsense mutations and in six patients with splice site mutations of the NF2 gene. The statistical analysis showed a significant lower risk of choroidal alterations in patients with somatic mosaicism, deletions and unfound mutations.

CONCLUSION

Using fluorescence angiography pathological changes of the macular region can be detected in NF2 patients. The ophthalmic examination, which often is limited to the anterior eye segment, may play a role in finding the diagnosis in incomplete NIH criteria. The presented study shows chorioretinal hyperfluorecences without leakage of the macular region, which might be considered as a forme fruste of a hamartoma. Choroidal hyperfluorescences add to the spectrum of genotype-phenotype correlations in NF2.

A new locus for autosomal dominant posterior polar cataract in Moroccan Jews maps to chromosome 14q22-23

BACKGROUND

Posterior polar cataract is a clinically distinctive opacity located at the back of the lens. It is commonly acquired in age related cataract, and may infrequently occur in pedigrees with congenital cataract. To date, five loci for autosomal dominant congenital posterior polar cataract have been identified. These include two genes, CRYAB and PITX3, on chromosomes 11q and 10q respectively, and three loci with as yet unknown genes on chromosomes 1p, 16q and 20p.

PURPOSE

To find the chromosomal location of a gene causing autosomal dominant congenital posterior polar cataract in three Moroccan Jewish families.

METHODS

A whole genome scan was performed using microsatellite markers spaced at approximately 10 cM intervals. For fine mapping, five additional microsatellite markers were genotyped. Two-point lod scores were calculated using MLINK software, from the LINKAGE program package. After linkage was established, several positional candidate genes were assessed by PCR based DNA sequencing.

RESULTS

The new cataract locus was mapped to an 11.3 cM interval between D14S980 and D14S1069 on chromosome 14q22-23. A maximum two point lod score of 5.19 at theta = 0 was obtained with the markersD14S274. The positional and functional candidate genes SIX1, SIX4, SIX6, OTX2, and ARHJ were excluded as the cause of cataract in these families.

CONCLUSION

An as yet unidentified gene associated with posterior polar cataract maps to the long arm of chromosome 14q22-23.

Ophthalmologic manifestations of cutaneous conditions

Many cutaneous conditions have associated ophthalmologic findings, which are important to recognize for both dermatologists and ophthalmologists. This review highlights some important ophthalmologic manifestations associated with neurocutaneous syndromes and inherited connective tissue diseases.

Ophthalmologic findings and long-term course in patients with neurofibromatosis type 2

PURPOSE

To evaluate ophthalmologic findings and long-term course in patients with neurofibromatosis type 2 (NF2).

DESIGN

Retrospective observational case series.

METHODS

SETTING

Single-center institutional practice.

STUDY POPULATION

Thirty referred patients with NF2 were enrolled from 1991 to 2003 and underwent at least one thorough neuroophthalmologic examination. Follow-up of 23 patients ranged from 4.3 to 12.5 years.

MAIN OUTCOME MEASURES

Visual function, structural ocular abnormalities, onset and type of presenting NF2-related symptoms, and number of central nervous system tumors.

RESULTS

Initial symptoms for patients with early-onset NF2 mostly comprised ophthalmologic symptoms (n = 7) and lower motor neuron extremity weakness (n = 6), as opposed to eighth nerve impairment (n = 11) in late disease onset. NF2-specific ocular findings were noted in 83% of all patients (94% childhood onset; 67% adult onset): 67% had cataracts, 40% epiretinal membranes, 3% hamartoma, 13% disk gliomas, and 27% optic nerve sheath meningiomas. Only 14% in the childhood-onset group-as opposed to 78% in the adult-onset group-sustained visual acuity of 1.0 in both eyes at final examination. Significantly more patients with early onset of symptoms developed multiple central nervous system tumors (P = .004) and showed a higher amount of NF2-specific findings (P = .015).

CONCLUSIONS

Initial manifestations of NF2 differ between children and adults. NF2-specific ophthalmologic findings can help establish the diagnosis. Symptom onset at a young age is clearly a risk factor for marked disease progression. These patients should be carefully followed because survival rates have increased, and vision becomes increasingly important as the disease progresses.

Neurofibromatosis types 1 and 2

BACKGROUND

Neurofibromatosis types 1 and 2 (NF1 and NF2) are autosomal dominant neurocutaneous disorders with some similarities and many differences. They are frequently discussed together and often confused for one another by clinicians. Both disorders have widely variable presentations and degrees of severity. A thorough understanding of these complex disorders is essential for proper medical management, anticipatory care, and patient education.

REVIEW SUMMARY

In this article, the clinical features, genetics, pathogenesis, and management of neurofibromatosis types 1 and 2 are reviewed and compared.

CONCLUSIONS

NF1 and NF2 are complex genetic disorders with numerous manifestations and wide phenotypic variability. The complex nature of these disorders requires coordinated multidisciplinary care.

Renal vascular disease in neurofibromatosis type 2: association or coincidence?

Neurofibromatosis type 2 (NF2) remains a challenging diagnosis in childhood where there may be no neurological involvement. A 12-month-old male in whom NF2 was suspected because of characteristic ophthalmological and cutaneous lesions is reported. Cranial MRI showed no tumours. A pathogenic mutation was identified on NF2 gene analysis. The child developed hypertension due to renal vascular disease. Although renal vascular disease is a recognized complication of neurofibromatosis type 1 (NF1), it has not been reported in NF2.

Persistent hyperplastic primary vitreous in association with neurofibromatosis 2

We describe a father and son with persistent hyperplastic primary vitreous occurring in association with neurofibromatosis 2. This report demonstrates rare vertical transmission compatible with autosomal dominant inheritance and the uncommon association of the autosomal dominant systemic disorder neurofibromatosis 2.

[Dragged disc syndrome in a patient presenting neurofibromatosis type II: a case study]

We report a case of dragged disc syndrome associated with neurofibromatosis type II (NF2). A 5-year-old girl with amblyopia (right eye, 20/200; left eye, 20/40) presented with dragged disk syndrome and a posterior subcapsular cataract in the left eye associated with an epiretinal membrane in the right eye. Five years later, she developed exophthalmos in the right eye associated with a cervical mass. MRI revealed schwannoma developing in the left optic nerve sheath associated with a cervicothoracic schwannoma. The child was diagnosed with NF2. Association of posterior subcapsular cataract with macular epiretinal membranes is highly suggestive of NF2, although the dragged disk syndrome has not been previously reported in NF2 to our knowledge. It may also be an ocular feature of this disease.

Vestibular schwannoma growth rates in neurofibromatosis type 2 natural history consortium subjects

OBJECTIVE

To determine the amount of growth in vestibular schwannomas in Neurofibromatosis type 2 (NF2) patients from diagnosis through short-term (up to 2 yr) and long-term (up to 4 yr) follow-up.

STUDY DESIGN

Retrospective magnetic resonance imaging (MRI) films were obtained on subjects enrolled in the NF2 Natural History study and examined for changes in vestibular schwannoma size over time.

SETTING

Data were collected from nine foreign and domestic NF2 centers, including hospital-based, academic, and tertiary care centers.

SUBJECTS

NF2 patients with MRI data and at least one follow-up examination within 9 months to 2 years of diagnosis were included; n=56 patients with 84 lesions for evaluation of growth.

INTERVENTION

Routine, clinically obtained, magnetic resonance images were digitized and measured using image management software. Short-term follow-up was defined as up to 2 years (n=84 lesions), and long-term follow-up was defined as 3 to 4 years (n=29 lesions).

OUTCOME MEASURES

Vestibular schwannoma size was assessed using anterior-posterior, medial-lateral, and greatest diameter linear measurements.

RESULTS

Vestibular schwannomas increased in size (at least 5 mm) in 8% of the vestibular schwannomas across short-term follow-up. At long-term follow-up, 13% of the tumors had increased in size. On average, schwannomas increased in greatest diameter 1.3 mm per year across short-term follow-up.

CONCLUSION

Slightly greater than 1 in 10 diagnosed NF2-related vestibular schwannomas increased in size by at least 5 mm by 4 years of follow-up, if still untreated at that time.

The morphology and natural history of childhood cataracts

The morphology of congenital cataract reflects a combination of the timing and nature of the cause, the anatomy of the lens including its capsule, its development, and changes that take place with time. Morphology may variably affect prognosis, give a clue to the etiology and the age of onset and, in an isolated case, sometimes suggest heritability. The spectrum of morphological variations is enormous and can be complex. A comprehensive approach is to classify the variations according to the area of the lens involved, and sub-dividing them by a detailed description of the shape and appearance. Each specific morphological type is then analyzed determining the etiology, visual prognosis, and management. The use of gene markers has allowed many of these variations to be identified and categorized. Cataracts in childhood can involve the whole lens, in which case they are called total, Morgagnian, or disk-like. They can affect only the center of the lens: lamellar, nuclear, oil droplet, cortical, or coronary. They can be anterior: anterior polar, anterior subcapsular, or anterior lenticonus. The posterior aspect of the lens can also be affected in different fashions: Mittendorf's dot, posterior lenticonus, posterior cortical cataracts, or posterior subcapsular. There are five more forms that must be described separately: punctuate lens opacities, sutural cataracts, coralliform or crystalline, wedge-shaped, and persistent hyperplastic primary vitreous.

A comparative cDNA microarray analysis reveals a spectrum of genes regulated by Pax6 in mouse lens

BACKGROUND

Pax6 is a transcription factor that is required for induction, growth, and maintenance of the lens; however, few direct target genes of Pax6 are known.

RESULTS

In this report, we describe the results of a cDNA microarray analysis of lens transcripts from transgenic mice over-expressing Pax6 in lens fibre cells in order to narrow the field of potential direct Pax6 target genes. This study revealed that the transcript levels were significantly altered for 508 of the 9700 genes analysed, including five genes encoding the cell adhesion molecules beta1-integrin, JAM1, L1 CAM, NCAM-140 and neogenin. Notably, comparisons between the genes differentially expressed in Pax6 heterozygous and Pax6 over-expressing lenses identified 13 common genes, including paralemmin, GDIbeta, ATF1, Hrp12 and Brg1. Immunohistochemistry and Western blotting demonstrated that Brg1 is expressed in the embryonic and neonatal (2-week-old) but not in 14-week adult lenses, and confirmed altered expression in transgenic lenses over-expressing Pax6. Furthermore, EMSA demonstrated that the BRG1 promoter contains Pax6 binding sites, further supporting the proposition that it is directly regulated by Pax6.

CONCLUSIONS

These results provide a list of genes with possible roles in lens biology and cataracts that are directly or indirectly regulated by Pax6.

Loss of heterozygosity for the NF2 gene in retinal and optic nerve lesions of patients with neurofibromatosis 2

Individuals affected with the neurofibromatosis 2 (NF2) cancer predisposition syndrome develop specific ocular lesions. To determine whether these lesions result from altered NF2 gene expression, microdissection and PCR were used to investigate 40 ocular lesions from seven eyes of four NF2 patients for LOH, with markers that flank the NF2 gene on chromosome 22q. NF2 protein (merlin) expression was also evaluated in these lesions, using immunohistochemistry. Retinal hamartoma was observed in all seven eyes, including one with combined pigment epithelial and retinal hamartoma (CPERH). Retinal tufts were present in four eyes (three patients), retinal dysplasia in two eyes (two patients), optic nerve neurofibroma in one eye, iris naevoid hyperplasia in two eyes (two patients) and pseudophakia in all eyes. Markers were informative in three patients (six eyes from three unrelated families). One patient was non-informative due to prolonged decalcification. All retinal and optic nerve, but not iris lesions, demonstrated consistent LOH for the NF2 gene. Merlin was not expressed in the retina, optic nerve, or iris lesions. These results suggest that inactivation of the NF2 gene is associated with the formation of a variety of retinal and optic nerve lesions in NF2 patients.

Presymptomatic diagnosis for children of sporadic neurofibromatosis 2 patients: a method based on tumor analysis

PURPOSE

To provide presymptomatic diagnosis for children of sporadic neurofibromatosis 2 patients in whom no NF2-mutations were found by screening their blood-DNA.

METHODS

Tumors of four patients were analyzed for NF2 allele losses and mutations.

RESULTS

Nonsense NF2 mutations and NF2 allele losses were found in all tumors. None of these alterations was found in any of eight children examined, suggesting that these children did not inherit the disease.

CONCLUSIONS

Finding two genetic alterations of a tumor suppressor gene in associated tumors is useful for presymptomatic diagnosis. Identification of the lost allele in tumors alone also enables exclusion of disease transmission in 50% of cases.

Monocular elevator paresis in neurofibromatosis type 2

A retrospective review of 29 consecutive unselected patients referred for neuro-ophthalmic evaluation after the diagnosis of neurofibromatosis type 2 (NF2) showed that four of them had a monocular elevator paresis. In two of the four MRI demonstrated lesions, presumed to be schwannomas, of the third nerve. These findings indicate that monocular elevator paresis is a common neuro-ophthalmic finding in NF2, which the authors suspect is probably a sign of third nerve infiltration or compression by a schwannoma.

Neuro-ophthalmology of the phacomatoses

The phacomatoses are a group of disorders that feature multiple hamartomas of the central and peripheral nervous system, eye, skin, and viscera. Most of these disorders have a well-defined Mendelian pattern of inheritance because of a mutation in a single gene which has been identified. In other instances, no clear patterns of inheritance or genetic susceptibility have been recognized. The combination of ocular and central nervous system manifestations in patients with phacomatoses makes neuro-ophthalmologic evaluation particularly important in diagnosis and management. This review provides an overview of the phacomatoses with emphasis on recent reports of significance to neuro-ophthalmology.

Neurofibromatosis type 2

Neurofibromatosis type 2 is an often devastating autosomal dominant disorder which, until relatively recently, was confused with its more common namesake neurofibromatosis type 1. Subjects who inherit a mutated allele of the NF2 gene inevitably develop schwannomas, affecting particularly the superior vestibular branch of the 8th cranial nerve, usually bilaterally. Meningiomas and other benign central nervous system tumours such as ependymomas are other common features. Much of the morbidity from these tumours results from their treatment. It is now possible to identify the NF2 mutation in most families, although about 20% of apparently sporadic cases are actually mosaic for their mutation. As a classical tumour suppressor, inactivation of the NF2 gene product, merlin/schwannomin, leads to the development of both NF2 associated and sporadic tumours. Merlin/schwannomin associates with proteins at the cell cytoskeleton near the plasma membrane and it inhibits cell proliferation, adhesion, and migration.

Restoration of hearing with an auditory brainstem implant in a patient with neurofibromatosis type 2--case report

A 25-year-old male with neurofibromatosis type 2 had hearing restored with an auditory brainstem implant (ABI) after removal of an acoustic schwannoma. The ABI allows the patient to discern many different environment sounds and is a significant adjunct to lip-reading, enabling conversation with people who have clear pronunciation without the necessity for writing.

Calpain-dependent proteolysis of NF2 protein: involvement in schwannomas and meningiomas

The neurofibromatosis type 2 (NF2) protein, known as merlin or schwannomin, is a tumor suppressor, and the NF2 gene has been found to be mutated in the majority of schwannomas and meningiomas, including both sporadically occurring and familial NF2 cases. Although the development of these tumors depends on the loss of merlin, the presence of tumors lacking detectable NF2 mutations suggests different mechanisms for inactivating merlin. Recent studies have demonstrated cleavage of merlin by calpain, a calcium-dependent neutral cysteine protease, and marked activation of the calpain system resulting in the degradation of merlin in these tumors. Increased turnover of merlin by calpain in some schwannomas and meningiomas exemplifies tumorigenesis linked to the calpain-mediated proteolytic pathway.