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RG, B., C. GJ, V. MD, S. SN, S. H-A, and P. - M. D, "A paleoimaging study of human mummies held in the Mother Church of Gangi, Sicily: Implications for mass casualty methodology", Forensic Imaging, vol. 23, pp. 200416, 2020.
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Zaki, M. S., A. Abdel-Aleem, G. Abdel-Salam, S. E. Marsh, J. L. Silhavy, A. J. Barkovich, M. E. Ross, S. N. Saleem, W. B. Dobyns, and J. G. Gleeson, "The molar tooth sign A new Joubert syndrome and related cerebellar disorders classification system tested in Egyptian families", Neurology, vol. 70, no. 7: Lippincott Williams & Wilkins, pp. 556–565, 2008. Abstract

Joubert syndrome and related cerebellar disorders (JSRD) are a group of recessive congenital ataxia conditions usually showing neonatal hypotonia, dysregulated breathing rhythms, oculomotor apraxia, and mental retardation. The pathognomonic finding in JSRD is the unique molar tooth sign (MTS) on brain imaging. There is a tremendously broad spectrum of signs and symptoms mainly including kidney, retina, and liver disease, along with polydactyly and facial dysmorphisms. Here we propose a new diagnostic classification within JSRD that includes four major subtypes. To test this classification, we performed a systematic recruitment and genetic evaluation from a single referral center in Egypt. Thirteen families were identified, four showed evidence of linkage to one of the four known genetic loci, three showed novel AHI1 mutations, and nine were excluded from known loci. Each family could be classified into one of the four subtypes. This classification may thus be useful in the evaluation of patients with JSRD.

GLOSSARY: BUN = blood urinary nitrogen; COACH = cerebellar vermis hypo/aplasia-oligophrenia-ataxia-ocular coloboma-hepatic fibrosis; CORS = cerebello-oculo-renal syndrome; CVH = cerebellar vermis hypoplasia; DAS = Dekaban-Arima syndrome; DWM = Dandy-Walker malformation; JSRD = Joubert syndrome and related cerebellar disorders; LCA = Leber congenital amaurosis; lod = logarithm of odds score; MKS = Meckel-Gruber syndrome; MTS = molar tooth sign; NPH = nephronophthisis; NRC = National Research Center; OFD-VI = oro-facio-digital syndrome type VI; PCH = pontocerebellar hypoplasia; RHO = rhombencephalosynapsis; SLS = Senior-Loken syndrome.

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Escande-Beillard, N., A. Loh, S. N. Saleem, K. Kanata, Y. Hashimoto, U. Altunoglu, A. Metoska, J. Grandjean, F. M. Ng, O. Pomp, et al., "Loss of PYCR2 Causes Neurodegeneration by Increasing Cerebral Glycine Levels via SHMT2.", Neuron, vol. 107, issue 1, pp. 82-94.e6, 2020. Abstract

Patients lacking PYCR2, a mitochondrial enzyme that synthesizes proline, display postnatal degenerative microcephaly with hypomyelination. Here we report the crystal structure of the PYCR2 apo-enzyme and show that a novel germline p.Gly249Val mutation lies at the dimer interface and lowers its enzymatic activity. We find that knocking out Pycr2 in mice phenocopies the human disorder and depletes PYCR1 levels in neural lineages. In situ quantification of neurotransmitters in the brains of PYCR2 mutant mice and patients revealed a signature of encephalopathy driven by excessive cerebral glycine. Mechanistically, we demonstrate that loss of PYCR2 upregulates SHMT2, which is responsible for glycine synthesis. This hyperglycemia could be partially reversed by SHMT2 knockdown, which rescued the axonal beading and neurite lengths of cultured Pycr2 knockout neurons. Our findings identify the glycine metabolic pathway as a possible intervention point to alleviate the neurological symptoms of PYCR2-mutant patients.

Guemez-Gamboa, A., A. O. Çağlayan, V. Stanley, A. Gregor, M. S. Zaki, S. N. Saleem, D. Musaev, J. McEvoy-Venneri, D. Belandres, N. Akizu, et al., "Loss of Protocadherin-12 Leads to Diencephalic-Mesencephalic Junction Dysplasia Syndrome.", Annals of neurology, vol. 84, issue 5, pp. 638-647, 2018 Nov. Abstract

OBJECTIVE: To identify causes of the autosomal-recessive malformation, diencephalic-mesencephalic junction dysplasia (DMJD) syndrome.

METHODS: Eight families with DMJD were studied by whole-exome or targeted sequencing, with detailed clinical and radiological characterization. Patient-derived induced pluripotent stem cells were derived into neural precursor and endothelial cells to study gene expression.

RESULTS: All patients showed biallelic mutations in the nonclustered protocadherin-12 (PCDH12) gene. The characteristic clinical presentation included progressive microcephaly, craniofacial dysmorphism, psychomotor disability, epilepsy, and axial hypotonia with variable appendicular spasticity. Brain imaging showed brainstem malformations and with frequent thinned corpus callosum with punctate brain calcifications, reflecting expression of PCDH12 in neural and endothelial cells. These cells showed lack of PCDH12 expression and impaired neurite outgrowth.

INTERPRETATION: DMJD patients have biallelic mutations in PCDH12 and lack of protein expression. These patients present with characteristic microcephaly and abnormalities of white matter tracts. Such pathogenic variants predict a poor outcome as a result of brainstem malformation and evidence of white matter tract defects, and should be added to the phenotypic spectrum associated with PCDH12-related conditions. Ann Neurol 2018;84:646-655.

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