@article {514, title = {Loss of Protocadherin-12 Leads to Diencephalic-Mesencephalic Junction Dysplasia Syndrome.}, journal = {Ann Neurol}, volume = {84}, year = {2018}, month = {2018 Nov}, pages = {638-647}, 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.

}, issn = {1531-8249}, doi = {10.1002/ana.25327}, author = {Guemez-Gamboa, Alicia and {\c C}a{\u g}layan, Ahmet Okay and Stanley, Valentina and Gregor, Anne and Zaki, Maha S and Saleem, Sahar N and Musaev, Damir and McEvoy-Venneri, Jennifer and Belandres, Denice and Akizu, Naiara and Silhavy, Jennifer L and Schroth, Jana and Rosti, Rasim Ozgur and Copeland, Brett and Lewis, Steven M and Fang, Rebecca and Issa, Mahmoud Y and Per, H{\"u}seyin and G{\"u}m{\"u}{\c s}, Hakan and Bayram, Ayse Kacar and Kumanda{\c s}, Sefer and Akg{\"u}m{\"u}{\c s}, G{\"o}zde Tu{\u g}ce and Erson-Omay, Emine Z and Yasuno, Katsuhito and Bilguvar, Kaya and Heimer, Gali and Pillar, Nir and Shomron, Noam and Weissglas-Volkov, Daphna and Porat, Yuval and Einhorn, Yaron and Gabriel, Stacey and Ben-Zeev, Bruria and G{\"u}nel, Murat and Gleeson, Joseph G} }