Xp22.2 Chromosomal Duplication in Familial Intracranial Arachnoid Cyst

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.

Fetal arachnoid cyst: characteristics, management in pregnancy, and neurodevelopmental outcomes

Arachnoid cysts are rarely found during the prenatal period and can exist in any part of the brain as extra-axial cysts. These cysts are usually found after the second trimester and should be differentiated from other types of brain cysts and tumors using ultrasonography and magnetic resonance imaging. Serial sonographic examinations are necessary to evaluate associated central nervous system (CNS) or extra-CNS anomalies and changes in size or shape during pregnancy. If there are other associated anomalies, prenatal genetic evaluations are strongly recommended. Surgical procedures are necessary after birth in approximately 30-60% of the patients. Most isolated cysts have favorable neurodevelopmental outcomes, although information on their prognosis is limited.

Intracranial Venous Sinus Stenting in Idiopathic Intracranial Hypertension: A Case Report and Review of the Literature

We describe a case of severe headaches, double vision, and progressive vision loss secondary to a ruptured intracranial cyst (IAC) in a 31-year-old woman with no relevant past medical history. The case is peculiar because drainage of the subdural hygroma led to a minimal improvement in vision with persistent elevated intracranial pressure (ICP). Further exploration revealed transverse sinus stenosis necessitating stenting. Evaluation post-stenting showed marked reduction of ICP and improvement in symptoms. This report underscores the importance of comprehensive work-up and suspicion of multiple underlying etiologies that may be crucial to complete resolution of presenting symptoms in some cases. We provide an overview of the clinical indications and evidence for venous sinus stenting in treating idiopathic intracranial hypertension (IIH).

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.

Familial intracranial arachnoid cysts with a missense mutation (c.2576C > T) in RERE: A case report

RATIONALE

Arachnoid cysts are relatively common intracranial space-occupying lesions; nevertheless, familial intracranial arachnoid cysts are extremely rare, with only a few cases having been reported.

PATIENT CONCERNS

The proband was a 7-year-old girl who had experienced generalized tonic-clonic seizures 5 times in the 8 days prior to admission. Nine months later, her 6-year-old younger female cousin presented to us with a 3-day history of headache.

DIAGNOSES

Brain magnetic resonance imaging (MRI) confirmed the diagnosis of arachnoid cyst for both of the girls.

INTERVENTIONS

A cyst-peritoneal shunting and cyst fenestration were performed for the 7-year-old girl and her cousin separately. Sanger sequencing revealed a heterozygous missense mutation (c.2576C > T) in the Arginine-Glutamic Acid Dipeptide Repeats gene (RERE).

OUTCOMES

The outcome was favorable and the follow-up was uneventful.

LESSONS

We hypothesize that the mutation in RERE may be associated with the pathogenesis of familial intracranial arachnoid cysts.