Familial arachnoid cysts associated with oculopharyngeal muscular dystrophy

Familial and syndromic forms of arachnoid cyst implicate genetic factors in disease pathogenesis

Arachnoid cysts (ACs) are the most common space-occupying lesions in the human brain and present significant challenges for clinical management. While most cases of ACs are sporadic, nearly 40 familial forms have been reported. Moreover, ACs are seen with increased frequency in multiple Mendelian syndromes, including Chudley-McCullough syndrome, acrocallosal syndrome, and autosomal recessive primary ciliary dyskinesia. These findings suggest that genetic factors contribute to AC pathogenesis. However, traditional linkage and segregation approaches have been limited in their ability to identify causative genes for ACs because the disease is genetically heterogeneous and often presents asymptomatically and sporadically. Here, we comprehensively review theories of AC pathogenesis, the genetic evidence for AC formation, and discuss a different approach to AC genomics that could help elucidate this perplexing lesion and shed light on the associated neurodevelopmental phenotypes seen in a significant subset of these patients.

Familial arachnoid cysts: a review of 35 families

INTRODUCTION

Arachnoid cysts are commonly considered congenital lesions, but this has not been proven. With the development of neuroimaging and DNA testing technology, more cases of familial arachnoid cysts have been reported. Herein, we review such cases.

MATERIALS AND METHODS

The PubMed, Embase, and Web of Science databases were searched for case reports of arachnoid cysts published through April 2018. Case reports were included only if two or more related patients were diagnosed with an arachnoid cyst by neuroimaging or intraoperatively. For each report, the following data were extracted: first author name, date of publication, number of families, number of patients, location of the arachnoid cysts, patient age, patient sex, and genetic mutations and associated disease.

RESULTS

Our searches identified 33 case reports involving 35 families and 115 patients. The locations of arachnoid cysts were similar in 25 of the 35 families. Spinal extradural arachnoid cysts were reported most often, followed by arachnoid cysts in the middle fossa and posterior fossa. A left-sided predominance was noticed for arachnoid cysts of the middle fossa. Mutation of the FOXC2 gene was reported most often, and arachnoid cysts may be associated with mutations on chromosome 16.

CONCLUSIONS

Although the origin of arachnoid cysts is believed to have a genetic component by some researchers, the genes associated with arachnoid cysts remain unknown. Unfortunately, the evidence remains insufficient.

Atypical Features in a Large Turkish Family Affected with Friedreich Ataxia

Here, we describe the clinical features of several members of the same family diagnosed with Friedreich ataxia (FRDA) and cerebral lesions, demyelinating neuropathy, and late-age onset without a significant cardiac involvement and presenting with similar symptoms, although genetic testing was negative for the GAA repeat expansion in one patient of the family. The GAA repeat expansion in the frataxin gene was shown in all of the family members except in a young female patient. MRI revealed arachnoid cysts in two patients; MRI was consistent with both cavum septum pellucidum-cavum vergae and nodular signal intensity increase in one patient. EMG showed demyelinating sensorimotor polyneuropathy in another patient. The GAA expansion-negative 11-year-old female patient had mental-motor retardation, epilepsy, and ataxia. None of the patients had significant cardiac symptoms. Description of FRDA families with different ethnic backgrounds may assist in identifying possible phenotypic and genetic features of the disease. Furthermore, the genetic heterogeneity observed in this family draws attention to the difficulty of genetic counseling in an inbred population and to the need for genotyping all affected members before delivering comprehensive genetic counseling.

Arachnoid cysts

Arachnoid cysts are fluid-filled duplications or splittings of the arachnoid layer with a content which is similar but not equal to the cerebrospinal fluid. Arachnoid cysts are not actual neurodegenerative disorders, rather the underlying defect of the texture of the arachnoid layer is probably congenital in nature. They can occur sporadically or can be associated with other malformations or diseases. Arachnoid cysts may be discovered in early childhood. However, they can develop de novo, grow or decrease in size. They may be diagnosed by ultrasound screening in the fetal period or be discovered during childhood or adulthood. Many arachnoid cysts are asymptomatic.Treatment strategies are discussed controversially. If they are diagnosed incidentally or are correlated with only very mild symptoms, a conservative management with follow-up imaging may be favored. If they grow, they can cause headaches, seizures or other neurological symptoms and require neurosurgical treatment. This chapter addresses aspects of pathogenesis, clinical symptoms, indication for neurosurgical treatment and treatment options.

Mirror-image arachnoid cysts in a pair of monozygotic twins: a case report and review of the literature

Mirror-imaging of arachnoid cysts (ACs) in monozygotic twins (MZ) is extremely rare. We describe a pair of MZ who developed mirror-imaging of ACs in the temporal fossas, and we also review the literature. Brain computer tomography (CT) and Magnetic Resonance Imaging (MRI) of the MZ revealed mirror-imaging of vast lesions of cerebrospinal fluid intensity in their temporal fossas. This is the second ever report of such a case according to the available literature. Unlike the prior case, our patients were 14 months, which is a much younger age than the patients of the previous report. Consequently, our case is better in supporting a genetic origin in the pathogenesis of AC. The findings in our case indicate that early neuroimaging is mandatory in the counterpart of the symptomatic patient with AC, irrespective of the absence of symptoms.

Location, sidedness, and sex distribution of intracranial arachnoid cysts in a population-based sample

Object

The aim of this study was to examine the distribution of intracranial arachnoid cysts in a large and unselected patient population with special emphasis on sidedness and sex distribution.

Methods

In total, 299 patients with 305 arachnoid cysts were studied. These patients were consecutively referred to our department during a 20-year period from a well-defined geographical area with a stable population.

Results

There was a strong predilection (198 patients [66.2%]) for intracranial arachnoid cysts in the temporal fossa. Forty-two patients had cysts overlying the frontal convexity, 36 had cysts in the posterior fossa, and 23 patients had cysts in other, different locations. Of 269 cysts with clearly unilateral distribution, 163 were located on the left side and 106 on the right side. This difference resulted from the marked preponderance of temporal fossa cysts on the left side (left-to-right ratio 2.5:1; p < 0.0001 [adjusted < 0.0005]). For cysts in the cerebellopontine angle (CPA), there was preponderance on the right side (p = 0.001 [adjusted = 0.005]). Significantly more males than females had cysts in the temporal fossa (p = 0.002 [adjusted = 0.004]), whereas in the CPA a significant female preponderance was found (p = 0.016 [adjusted = 0.032]). For all other cyst locations, there was no difference between the 2 sexes.

Conclusions

Arachnoid cysts have a strong predilection for the temporal fossa. There is a sex dependency for some intracranial locations of arachnoid cysts, with temporal cysts occurring more frequently in men, and CPA cysts found more frequently in women. Furthermore, there is a strong location-related sidedness for arachnoid cysts, independent of patient sex. These findings and reports from the literature suggest a possible genetic component in the development of some arachnoid cysts.

Apparently novel genetic syndrome of pachygyria, mental retardation, seizure, and arachnoid cysts

We report on an apparently new syndrome in a consanguineous family with seven members, three of whom have cerebral anomalies including pachygyria and arachnoid cysts along with mental retardation and seizures. The two patients with seizure disorders also had multiple enlarged perivascular spaces seen in the white matter of the centrum semiovale. Our data provide a contribution to the accumulating knowledge on familial cerebral anomalies including arachnoid cysts and lissencephaly. Given the lack of mutation in known lissencephaly genes such as LIS1, 14-3-3epsilon, and DCX, this syndrome may constitute a new phenotype with autosomal recessive inheritance.

Bilateral temporal arachnoid cysts associated with tuberous sclerosis complex

The association between tuberous sclerosis complex and intracranial abnormalities such as hemimegalencephaly, schizencephaly, intracranial arterial aneurysms, and corpus callosum agenesis/dysplasia has been reported in the recent literature. However, the association between tuberous sclerosis complex and bilateral temporal arachnoid cysts has not been reported. A case of an 8-year-old boy with a mental impairment and epileptic seizures that began 5 years earlier is presented. The neuro-radiological findings are consistent with tuberous sclerosis complex associated with bitemporal arachnoid cysts. His epileptic seizures were treated with antiepileptic medications. To the authors' knowledge, this is the first reported case of tuberous sclerosis complex associated with bilateral arachnoid cysts of the temporal region. In such cases, arachnoid cysts may exacerbate the clinical picture.

Oculo-ectodermal syndrome: is arachnoid cyst a common finding?

Oculo-ectodermal syndrome is a rare condition characterized by aplasia cutis and epibulbar dermoids. We present the case of a 6-year-old girl with oculo-ectodermal syndrome, who was found to have an arachnoid cyst by head computed tomography. This is the third case of oculo-ectodermal syndrome with arachnoid cyst reported in the literature, and suggests that arachnoid cyst may be a phenotypic feature of oculo-ectodermal syndrome.

Familial arachnoid cysts

Arachnoid cysts are a relatively common incidental finding on neuroimaging studies of the brain. Although most cases are sporadic, there have been some reports of arachnoid cysts in several members of the same family. This report describes two additional families with three members affected in each one. Both families had members with arachnoid cysts in two consecutive generations. In one of the families, arachnoid cysts were associated with a deletion in the long arm of chromosome 16, an association not described previously. These descriptions suggest that in some cases arachnoid cysts may have a genetic basis.