@article {916, title = {Biallelic variants in HPDL, encoding 4-hydroxyphenylpyruvate dioxygenase-like protein, lead to an infantile neurodegenerative condition.}, journal = {Genet Med}, volume = {23}, year = {2021}, month = {2021 03}, pages = {524-533}, abstract = {

PURPOSE: Dioxygenases are oxidoreductase enzymes with roles in metabolic pathways necessary for aerobic life. 4-hydroxyphenylpyruvate dioxygenase-like protein (HPDL), encoded by HPDL, is an orphan paralogue of 4-hydroxyphenylpyruvate dioxygenase (HPD), an iron-dependent dioxygenase involved in tyrosine catabolism. The function and association of HPDL with human diseases remain unknown.

METHODS: We applied exome sequencing in a cohort of over 10,000 individuals with neurodevelopmental diseases. Effects of HPDL loss were investigated in vitro and in vivo, and through mass spectrometry analysis. Evolutionary analysis was performed to investigate the potential functional separation of HPDL from HPD.

RESULTS: We identified biallelic variants in HPDL in eight families displaying recessive inheritance. Knockout mice closely phenocopied humans and showed evidence of apoptosis in multiple cellular lineages within the cerebral cortex. HPDL is a single-exonic gene that likely arose from a retrotransposition event at the base of the tetrapod lineage, and unlike HPD, HPDL is mitochondria-localized. Metabolic profiling of HPDL mutant cells and mice showed no evidence of altered tyrosine metabolites, but rather notable accumulations in other metabolic pathways.

CONCLUSION: The mitochondrial localization, along with its disrupted metabolic profile, suggests HPDL loss in humans links to a unique neurometabolic mitochondrial infantile neurodegenerative condition.

}, keywords = {4-Hydroxyphenylpyruvate Dioxygenase, Animals, Dioxygenases, Exons, Mice, Mice, Knockout, Phenotype}, issn = {1530-0366}, doi = {10.1038/s41436-020-01010-y}, author = {Ghosh, Shereen G and Lee, Sangmoon and Fabunan, Rudy and Chai, Guoliang and Zaki, MAH S and Abdel-Salam, Ghada and Sultan, Tipu and Ben-Omran, Tawfeg and Alvi, Javeria Raza and McEvoy-Venneri, Jennifer and Stanley, Valentina and Patel, Aakash and Ross, Danica and Ding, Jeffrey and Jain, Mohit and Pan, Daqiang and L{\"u}bbert, Philipp and Kammerer, Bernd and Wiedemann, Nils and Verhoeven-Duif, Nanda M and Jans, Judith J and Murphy, David and Toosi, Mehran Beiraghi and Ashrafzadeh, Farah and Imannezhad, Shima and Karimiani, Ehsan Ghayoor and Ibrahim, Khalid and Waters, Elizabeth R and Maroofian, Reza and Gleeson, Joseph G} } @article {924, title = {Mutations in Spliceosomal Genes PPIL1 and PRP17 Cause Neurodegenerative Pontocerebellar Hypoplasia with Microcephaly.}, journal = {Neuron}, volume = {109}, year = {2021}, month = {2021 01 20}, pages = {241-256.e9}, abstract = {

Autosomal-recessive cerebellar hypoplasia and ataxia constitute a group of heterogeneous brain disorders caused by disruption of several fundamental cellular processes. Here, we identified 10 families showing a neurodegenerative condition involving pontocerebellar hypoplasia with microcephaly (PCHM). Patients harbored biallelic mutations in genes encoding the spliceosome components Peptidyl-Prolyl Isomerase Like-1 (PPIL1) or Pre-RNA Processing-17 (PRP17). Mouse knockouts of either gene were lethal in early embryogenesis, whereas PPIL1 patient mutation knockin mice showed neuron-specific apoptosis. Loss of either protein affected splicing integrity, predominantly affecting short and high GC-content introns and genes involved in brain disorders. PPIL1 and PRP17 form an active isomerase-substrate interaction, but we found that isomerase activity is not critical for function. Thus, we establish disrupted splicing integrity and "major spliceosome-opathies" as a new mechanism underlying PCHM and neurodegeneration and uncover a non-enzymatic function of a spliceosomal proline isomerase.

}, keywords = {Amino Acid Sequence, Animals, Cell Cycle Proteins, Cerebellar Diseases, Cohort Studies, Female, Gene Knockout Techniques, HEK293 Cells, Heredodegenerative Disorders, Nervous System, Humans, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Microcephaly, Mutation, Pedigree, Peptidylprolyl Isomerase, Protein Structure, Secondary, Protein Structure, Tertiary, RNA Splicing Factors, Spliceosomes}, issn = {1097-4199}, doi = {10.1016/j.neuron.2020.10.035}, author = {Chai, Guoliang and Webb, Alice and Li, Chen and Antaki, Danny and Lee, Sangmoon and Breuss, Martin W and Lang, Nhi and Stanley, Valentina and Anzenberg, Paula and Yang, Xiaoxu and Marshall, Trevor and Gaffney, Patrick and Wierenga, Klaas J and Chung, Brian Hon-Yin and Tsang, Mandy Ho-Yin and Pais, Lynn S and Lovgren, Alysia Kern and VanNoy, Grace E and Rehm, Heidi L and Mirzaa, Ghayda and Leon, Eyby and Diaz, Jullianne and Neumann, Alexander and Kalverda, Arnout P and Manfield, Iain W and Parry, David A and Logan, Clare V and Johnson, Colin A and Bonthron, David T and Valleley, Elizabeth M A and Issa, Mahmoud Y and Abdel-Ghafar, Sherif F and Abdel-Hamid, Mohamed S and Jennings, Patricia and Zaki, MAH S and Sheridan, Eamonn and Gleeson, Joseph G} }