Congenital hydrocephalus (CH), featuring markedly enlarged brain ventricles, is thought to arise from failed cerebrospinal fluid (CSF) homeostasis and is treated with lifelong surgical CSF shunting with substantial morbidity. CH pathogenesis is poorly understood. Exome sequencing of 125 CH trios and 52 additional probands identified three genes with significant burden of rare damaging de novo or transmitted mutations: TRIM71 (p = 2.15 × 10), SMARCC1 (p = 8.15 × 10), and PTCH1 (p = 1.06 × 10). Additionally, two de novo duplications were identified at the SHH locus, encoding the PTCH1 ligand (p = 1.2 × 10). Together, these probands account for ∼10% of studied cases. Strikingly, all four genes are required for neural tube development and regulate ventricular zone neural stem cell fate. These results implicate impaired neurogenesis (rather than active CSF accumulation) in the pathogenesis of a subset of CH patients, with potential diagnostic, prognostic, and therapeutic ramifications.
Introduction: Intracranial aneurysms are very rare in children. Although subarachnoidal hemorrhage (SAH) is by far the most common presentation of aneurysms in the majority of the pediatric case series, it is not rare for an unruptured aneurysm to present with a mass effect. Acute hydrocephalus is a common finding following aneurysmal SAH. However, this malady may develop even in the absence of SAH but secondary to direct obstruction by a giant aneurysm. This situation is extremely rare in children, with only a few known case reports in the literature. Case Report: We report the case of a 10-year-old girl who presented with signs and symptoms of acute hydrocephalus; further radiological evaluation revealed obstructive hydrocephalus and a giant posterior cerebral artery aneurysm. Following endovascular treatment of the aneurysm, hydrocephalus was completely resolved, and the patient was symptom free. Conclusion: Although they are very rare, giant intracranial aneurysms must be kept in mind during the differential diagnosis of pediatric acute hydrocephalus cases. Hydrocephalus may resolve spontaneously after the successful treatment of these aneurysms.
INTRODUCTION
Congenital hydrocephalus (CH), with an estimated prevalence of 1 in 1000 births, is the most common disease treated by pediatric neurosurgeons, and exerts a tremendous burden on the United States health care budget, consuming over $2 billion annually. Paradoxically, CH treatments remain inadequate, crude, and primarily symptomatic, comprised largely of surgical shunts riddled with infectious and mechanical complications. Despite evidence that genetic factors play a major role in the pathogenesis of CH an estimated 40% of human CH has a genetic etiology our knowledge of specific CH-causing mutations and their pathogenic mechanisms remains primitive. Understanding critical genetic drivers underlying human CH holds promise for the development of targeted therapies. However, traditional genetic approaches have been limited in their ability to identify causative CH genes because kindreds are rare, small in size, or appear to have sporadic inheritance patterns. Next-generation sequencing, and specifically whole exome sequencing (WES), can overcome these barriers to gene discovery.
METHODS
We performed whole-exome sequencing on DNA isolated from 130 patient-parent trios (affected patient and unaffected parents) and an additional 57 probands for a total of 187 CH patients with non-L1CAM primary CH. Exome-sequencing data from these 447 individuals was then analyzed to identify rare, de novo and transmitted mutations contributing to CH, and candidate mutations were subsequently confirmed by Sanger sequencing.
RESULTS
>Exome sequencing identified multiple novel and recurrent de novo and transmitted loss-of function gene mutations enriched in neurodevelopmental and ciliogenesis pathways. Binomial and case-control analyses confirmed exome-wide statistical significance of candidate genes, and functional modeling in Xenopus established gene causality.
CONCLUSION
These findings reveal novel disease-causing mutations in human CH, thereby providing new opportunities for improved prognostic assessment and non-invasive therapies.
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