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Congenital microcephaly causes smaller than average head circumference relative to age, sex and ethnicity and is most usually associated with a variety of neurodevelopmental disorders. The underlying etiology is highly heterogeneous and can be either environmental or genetic. Disruption of any one of multiple biological processes, such as those underlying neurogenesis, cell cycle and division, DNA repair or transcription regulation, can result in microcephaly. This etiological heterogeneity manifests in a clinical variability and presents a major diagnostic and therapeutic challenge, leaving an unacceptably large proportion of over half of microcephaly patients without molecular diagnosis. To elucidate the clinical and genetic landscapes of congenital microcephaly, we sequenced the exomes of 191 clinically diagnosed patients with microcephaly as one of the features. We established a molecular basis for microcephaly in 71 patients (37%), and detected novel variants in five high confidence candidate genes previously unassociated with this condition. We report a large number of patients with mutations in tubulin-related genes in our cohort as well as higher incidence of pathogenic mutations in MCPH genes. Our study expands the phenotypic and genetic landscape of microcephaly, facilitating differential clinical diagnoses for disorders associated with most commonly disrupted genes in our cohort.

Optic pathway gliomas represent 2 to 5% of brain tumors in children. Frequently asymptomatic, sometimes they demonstrate rapid growth, causing considerable visual dysfunction, neurologic deficits, and endocrine disturbances. Most optic pathway gliomas are diagnosed in patients with neurofibromatosis 1. Little is known about their natural course; therefore, there are no clear and widely accepted guidelines for their treatment. This study compared the clinical manifestations and natural history of sporadic and neurofibromatosis 1-associated optic pathway gliomas with regard to age at diagnosis, gender, and findings on neurologic, ophthalmologic, and neuroradiologic examinations in 83 children with optic pathway gliomas: 51 children with neurofibromatosis 1 and 32 children without any symptoms or signs of neurofibromatosis 1. A prospective study was performed in 21 patients with neurofibromatosis 1. In the rest of the patients with neurofibromatosis 1 and in 32 children with sporadic tumors, the analysis was carried out retrospectively. There was an increased incidence of females in the group of patients with neurofibromatosis 1 with optic pathway gliomas compared with the entire group of patients with neurofibromatosis 1 remaining for follow-up (P = .013). All optic pathway gliomas were found in children below 10 years of age, slightly earlier in the group without neurofibromatosis 1 (median age 4.6 vs 4.8 years). Children with optic pathway gliomas associated with neurofibromatosis 1 had predominantly multifocal lesions (P = .0001), whereas in the group without neurofibromatosis 1, isolated chiasmal involvement was more common (P = .002). Children with sporadic gliomas had significantly more frequently increased intracranial pressure, decreased visual acuity, and abnormalities of fundus of the eye at the time of diagnosis. The radiologic progression, visual deterioration, and endocrinologic complications were documented on follow-up more commonly in children with sporadic tumors. Our findings support the concept that there is an earlier and more severe clinical presentation of optic pathway gliomas in children with sporadic tumors than in those associated with neurofibromatosis 1.

The authors present an analysis of brain tumors diagnosed in the pediatric ward of the voivodship hospital in Rzeszów between 1988 and 1992. Age, sex and clinical manifestation leading to hospitalisation, localisation and histopathology of the tumors were assessed.