@article {986, title = {Dual activating FGFR1 mutations in pediatric pilomyxoid astrocytoma.}, journal = {Mol Genet Genomic Med}, volume = {9}, year = {2021}, month = {2021 02}, pages = {e1597}, abstract = {

BACKGROUND: Pilomyxoid astrocytomas are an aggressive subtype of astrocytoma, not graded by WHO, frequently located in hypothalamic/chiasmatic region, affecting diencephalic structures, and characterized by shorter survival and high recurrence rates. Pilomyxoid astrocytoma management remains controversial, with pathologic tissue diagnosis and relief of mass effect being the main goals of surgery while avoiding treatment-related morbidity, including vision loss, panhypopituitarism, and hypothalamic dysfunction. Chemotherapy (typically vincristine and carboplatin) in all pediatric patients and radiation therapy in pediatric patients over 5~years of age are used for treatment.

METHODS: We report clinical presentation, surgical management, and whole exome sequencing results in a pediatric patient with the subtotally resected pilomyxoid astrocytoma.

RESULTS: We identified two somatic activating missense mutations affecting FGFR1, including FGFR1 p.K656E and FGFR1 p.V561M. While the former is a known hotspot mutation that is both activating and transforming, the latter has been described as a gatekeeper mutation imparting resistance to FGFR inhibitors. Interestingly, both mutations were present with similar variant allele frequency within the tumor.

CONCLUSION: Similar variant allele frequencies of FGFR1 p.K656E and FGFR1 p.V561M mutations in our patient{\textquoteright}s tumor suggest that these mutations may have occurred at similar time points. Use of FGFR inhibitors in addition to STAT3 or PI3K/mTOR inhibition may prove a useful strategy in targeting our patient{\textquoteright}s pilomyxoid astrocytoma.

}, issn = {2324-9269}, doi = {10.1002/mgg3.1597}, author = {Fomchenko, Elena I and Reeves, Benjamin C and Sullivan, William and Marks, Asher M and Huttner, Anita and Kahle, Kristopher T and Erson-Omay, E Zeynep} } @article {96, title = {A patient with a novel homozygous missense mutation in FTO and concomitant nonsense mutation in CETP.}, journal = {J Hum Genet}, volume = {61}, year = {2016}, month = {2016 May}, pages = {395-403}, abstract = {

The fat mass and obesity associated (FTO) gene has previously been associated with a variety of diseases and conditions, notably obesity, acute coronary syndrome and metabolic syndrome. Reports describing mutations in FTO as well as in FTO animal models have further demonstrated a role for FTO in the development of the brain and other organs. Here, we describe a patient born of consanguineous union who presented with microcephaly, developmental delay, behavioral abnormalities, dysmorphic facial features, hypotonia and other various phenotypic abnormalities. Whole-exome sequencing revealed a novel homozygous missense mutation in FTO and a nonsense mutation in the cholesteryl ester transfer protein (CETP). Exome copy number variation analysis revealed no disease-causing large duplications or deletions within coding regions. Patient{\textquoteright}s, her parents{\textquoteright} and non-related control{\textquoteright} fibroblasts were analyzed for morphologic defects, abnormal proliferation, apoptosis and transcriptome profile. We have shown that FTO is located in the nucleus of cells from each tested sample. Western blot analysis demonstrated no changes in patient FTO. Quantitative (qPCR) analysis revealed slightly decreased levels of FTO expression in patient cells compared with controls. No morphological or proliferation differences between the patient and control fibroblasts were observed. There is still much to be learned about the molecular mechanisms by which mutations in FTO contribute to such severe phenotypes.

}, keywords = {Alpha-Ketoglutarate-Dependent Dioxygenase FTO, Apoptosis, Biopsy, Child, Preschool, Cholesterol Ester Transfer Proteins, Computational Biology, Consanguinity, DNA Copy Number Variations, DNA Mutational Analysis, Exome, Female, Gene Expression, Gene Expression Profiling, Genetic Association Studies, Genotype, High-Throughput Nucleotide Sequencing, Homozygote, Humans, Mutation, Missense, Phenotype, Transcriptome}, issn = {1435-232X}, doi = {10.1038/jhg.2015.160}, author = {{\c C}a{\u g}layan, Ahmet O and Tuysuz, Beyhan and Co{\c s}kun, S{\"u}leyman and Quon, Jennifer and Harmanc{\i}, Akdes S and Baranoski, Jacob F and Baran, Bur{\c c}in and Erson-Omay, E Zeynep and Henegariu, Octavian and Mane, Shrikant M and Bilguvar, Kaya and Yasuno, Katsuhito and G{\"u}nel, Murat} } @article {203, title = {Mutations in KATNB1 cause complex cerebral malformations by disrupting asymmetrically dividing neural progenitors.}, journal = {Neuron}, volume = {84}, year = {2014}, month = {2014 Dec 17}, pages = {1226-39}, abstract = {

Exome sequencing analysis of over 2,000 children with complex malformations of cortical development identified five independent (four homozygous and one compound heterozygous) deleterious mutations in KATNB1, encoding the regulatory subunit of the microtubule-severing enzyme Katanin. Mitotic spindle formation is defective in patient-derived fibroblasts, a consequence of disrupted interactions of mutant KATNB1 with KATNA1, the catalytic subunit of Katanin, and other microtubule-associated proteins. Loss of KATNB1 orthologs in zebrafish (katnb1) and flies (kat80) results in microcephaly, recapitulating the human phenotype. In the developing Drosophila optic lobe, kat80 loss specifically affects the asymmetrically dividing neuroblasts, which display supernumerary centrosomes and spindle abnormalities during mitosis, leading to cell cycle progression delays and reduced cell numbers. Furthermore, kat80 depletion results in dendritic arborization defects in sensory and motor neurons, affecting neural architecture. Taken together, we provide insight into the mechanisms by which KATNB1 mutations cause human cerebral cortical malformations, demonstrating its fundamental role during brain development.

}, keywords = {Adenosine Triphosphatases, Animals, Brain, Cell Count, Cell Division, Dendrites, Drosophila, Drosophila Proteins, Humans, Katanin, Mice, Microcephaly, Microtubule-Associated Proteins, Mutation, Neural Stem Cells, Neurogenesis, Optic Lobe, Nonmammalian, Spindle Apparatus, Zebrafish}, issn = {1097-4199}, doi = {10.1016/j.neuron.2014.12.014}, author = {Mishra-Gorur, Ketu and {\c C}a{\u g}layan, Ahmet Okay and Schaffer, Ashleigh E and Chabu, Chiswili and Henegariu, Octavian and Vonhoff, Fernando and Akg{\"u}m{\"u}{\c s}, G{\"o}zde Tu{\u g}ce and Nishimura, Sayoko and Han, Wenqi and Tu, Shu and Baran, Bur{\c c}in and G{\"u}m{\"u}{\c s}, Hakan and Dilber, Cengiz and Zaki, Maha S and Hossni, Heba A A and Rivi{\`e}re, Jean-Baptiste and Kayserili, H{\"u}lya and Spencer, Emily G and Rosti, Rasim O and Schroth, Jana and Per, H{\"u}seyin and Caglar, Caner and {\c C}a{\u g}lar, {\c C}a{\u g}ri and D{\"o}len, Duygu and Baranoski, Jacob F and Kumanda{\c s}, Sefer and Minja, Frank J and Erson-Omay, E Zeynep and Mane, Shrikant M and Lifton, Richard P and Xu, Tian and Keshishian, Haig and Dobyns, William B and Chi, Neil C and {\v S}estan, Nenad and Louvi, Angeliki and Bilguvar, Kaya and Yasuno, Katsuhito and Gleeson, Joseph G and G{\"u}nel, Murat} }