@article {935, title = {Genotypic diversity and phenotypic spectrum of infantile liver failure syndrome type 1 due to variants in LARS1.}, journal = {Genet Med}, volume = {22}, year = {2020}, month = {2020 11}, pages = {1863-1873}, abstract = {

PURPOSE: Biallelic variants in LARS1, coding for the cytosolic leucyl-tRNA synthetase, cause infantile liver failure syndrome 1 (ILFS1). Since its description in 2012, there has been no systematic analysis of the clinical spectrum and genetic findings.

METHODS: Individuals with biallelic variants in LARS1 were included through an international, multicenter collaboration including novel and previously published patients. Clinical variables were analyzed and functional studies were performed in patient-derived fibroblasts.

RESULTS: Twenty-five individuals from 15 families were ascertained including 12 novel patients with eight previously unreported variants. The most prominent clinical findings are recurrent elevation of liver transaminases up to liver failure and encephalopathic episodes, both triggered by febrile illness. Magnetic resonance image (MRI) changes during an encephalopathic episode can be consistent with metabolic stroke. Furthermore, growth retardation, microcytic anemia, neurodevelopmental delay, muscular hypotonia, and infection-related seizures are prevalent. Aminoacylation activity is significantly decreased in all patient cells studied upon temperature elevation in vitro.

CONCLUSION: ILFS1 is characterized by recurrent elevation of liver transaminases up to liver failure in conjunction with abnormalities of growth, blood, nervous system, and musculature. Encephalopathic episodes with seizures can occur independently from liver crises and may present with metabolic stroke.

}, keywords = {Humans, Liver Failure, Muscle Hypotonia, Mutation, Seizures}, issn = {1530-0366}, doi = {10.1038/s41436-020-0904-4}, author = {Lenz, Dominic and Smith, Desir{\'e}e E C and Crushell, Ellen and Husain, Ralf A and Salomons, Gajja S and Alhaddad, Bader and Bernstein, Jonathan A and Bianzano, Alyssa and Biskup, Saskia and Brennenstuhl, Heiko and Caldari, Dominique and Dikow, Nicola and Haack, Tobias B and Hanson-Kahn, Andrea and Harting, Inga and Horn, Denise and Hughes, Joanne and Huijberts, Maya and Isidor, Bertrand and Kathemann, Simone and Kopajtich, Robert and Kotzaeridou, Urania and K{\"u}ry, S{\'e}bastien and Lainka, Elke and Laugwitz, Lucia and Lupski, James R and Posey, Jennifer E and Reynolds, Claire and Rosenfeld, Jill A and Schr{\"o}ter, Julian and Vansenne, Fleur and Wagner, Matias and Wei{\ss}, Claudia and Wolffenbuttel, Bruce H R and Wortmann, Saskia B and K{\"o}lker, Stefan and Hoffmann, Georg F and Prokisch, Holger and Mendes, Marisa I and Staufner, Christian} } @article {720, title = {Xq22 deletions and correlation with distinct neurological disease traits in females: Further evidence for a contiguous gene syndrome.}, journal = {Hum Mutat}, volume = {41}, year = {2020}, month = {2020 01}, pages = {150-168}, abstract = {

Xq22 deletions that encompass PLP1 (Xq22-PLP1-DEL) are notable for variable expressivity of neurological disease traits in females ranging from a mild late-onset form of spastic paraplegia type 2 (MIM$\#$ 312920), sometimes associated with skewed X-inactivation, to an early-onset neurological disease trait (EONDT) of severe developmental delay, intellectual disability, and behavioral abnormalities. Size and gene content of Xq22-PLP1-DEL vary and were proposed as potential molecular etiologies underlying variable expressivity in carrier females where two smallest regions of overlap (SROs) were suggested to influence disease. We ascertained a cohort of eight unrelated patients harboring Xq22-PLP1-DEL and performed high-density array comparative genomic hybridization~and breakpoint-junction sequencing. Molecular characterization of Xq22-PLP1-DEL from 17 cases (eight herein and nine published) revealed an overrepresentation of breakpoints that reside within repeats (11/17, ~65\%) and the clustering of ~47\% of proximal breakpoints in a genomic instability hotspot with characteristic non-B DNA density. These findings implicate a potential role for genomic architecture in stimulating the formation of Xq22-PLP1-DEL. The correlation of Xq22-PLP1-DEL gene content with neurological disease trait in female cases enabled refinement of the associated SROs to a single genomic interval containing six genes. Our data support the hypothesis that genes contiguous to PLP1 contribute to EONDT.

}, keywords = {Child, Child, Preschool, Chromosome Breakpoints, Chromosome Deletion, Chromosome Mapping, Chromosomes, Human, X, Comparative Genomic Hybridization, Female, Genetic Association Studies, Genetic Predisposition to Disease, Humans, Male, Nervous System Diseases, Pedigree, Phenotype, Quantitative Trait, Heritable, Repetitive Sequences, Nucleic Acid, Sex Factors, Syndrome, X Chromosome Inactivation}, issn = {1098-1004}, doi = {10.1002/humu.23902}, author = {Hijazi, Hadia and Coelho, Fernanda S and Gonzaga-Jauregui, Claudia and Bernardini, Laura and Mar, Soe S and Manning, Melanie A and Hanson-Kahn, Andrea and Naidu, Sakkubai and Srivastava, Siddharth and Lee, Jennifer A and Jones, Julie R and Friez, Michael J and Alberico, Thomas and Torres, Barbara and Fang, Ping and Cheung, Sau Wai and Song, Xiaofei and Davis-Williams, Angelique and Jornlin, Carly and Wight, Patricia A and Patyal, Pankaj and Taube, Jennifer and Poretti, Andrea and Inoue, Ken and Zhang, Feng and Pehlivan, Davut and Carvalho, Claudia M B and Hobson, Grace M and Lupski, James R} } @article {547, title = {Autosomal recessive Stickler syndrome resulting from a COL9A3 mutation.}, journal = {Am J Med Genet A}, volume = {176}, year = {2018}, month = {2018 Dec}, pages = {2887-2891}, abstract = {

Stickler syndrome is a connective tissue disorder characterized by hearing loss, ocular anomalies, palatal defects, and skeletal abnormalities. The autosomal dominant form is the most common, but autosomal recessive forms have also been described. We report the second case of autosomal recessive Stickler syndrome due to homozygosity for a loss of function mutation in COL9A3, which encodes the α3 chain of type IX procollagen. The clinical features were similar to the previously described COL9A3 Stickler syndrome family, including moderate to severe sensorineural hearing loss, high myopia, and both tibial and femoral bowing at birth. Radiographs demonstrated abnormal capital femoral epiphyses and mild irregularities of the vertebral endplates. This case further establishes the phenotype associated with mutations in this gene. We suggest that loss of the α3 chain of type IX collagen results in a Stickler syndrome phenotype similar to that of the other autosomal recessive forms caused by mutations in genes encoding the α1 and α2 chains of type IX collagen.

}, issn = {1552-4833}, doi = {10.1002/ajmg.a.40647}, author = {Hanson-Kahn, Andrea and Li, Bing and Cohn, Daniel H and Nickerson, Deborah A and Bamshad, Michael J and Hudgins, Louanne} } @article {558, title = {MACF1 Mutations Encoding Highly Conserved Zinc-Binding Residues of the GAR Domain Cause Defects in Neuronal Migration and Axon Guidance.}, journal = {Am J Hum Genet}, volume = {103}, year = {2018}, month = {2018 12 06}, pages = {1009-1021}, abstract = {

To date, mutations in 15 actin- or microtubule-associated genes have been associated with the cortical malformation lissencephaly and variable brainstem hypoplasia. During a multicenter review, we recognized a rare lissencephaly variant with a complex brainstem malformation in three unrelated children. We searched our large brain-malformation databases and found another five children with this malformation (as well as one with a less severe variant), analyzed available whole-exome or -genome sequencing data, and tested ciliogenesis in two affected individuals. The brain malformation comprised posterior predominant lissencephaly and midline crossing defects consisting of absent anterior commissure and a striking W-shaped brainstem malformation caused by small or absent pontine crossing fibers. We discovered heterozygous de novo missense variants or an in-frame deletion involving highly conserved zinc-binding residues within the GAR domain of MACF1 in the first eight subjects. We studied cilium formation and found a higher proportion of mutant cells with short cilia than of control cells with short cilia. A ninth child had similar lissencephaly but~only subtle brainstem dysplasia associated with a heterozygous de novo missense variant in the spectrin repeat domain of MACF1. Thus, we report variants of the microtubule-binding GAR domain of MACF1 as the cause of a distinctive and most likely pathognomonic brain malformation. A~gain-of-function or dominant-negative mechanism appears likely given that many heterozygous mutations leading to protein truncation are included in the ExAC Browser. However, three de novo variants in MACF1 have been observed in large schizophrenia cohorts.

}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2018.10.019}, author = {Dobyns, William B and Aldinger, Kimberly A and Ishak, Gisele E and Mirzaa, Ghayda M and Timms, Andrew E and Grout, Megan E and Dremmen, Marjolein H G and Schot, Rachel and Vandervore, Laura and van Slegtenhorst, Marjon A and Wilke, Martina and Kasteleijn, Esmee and Lee, Arthur S and Barry, Brenda J and Chao, Katherine R and Szcza{\l}uba, Krzysztof and Kobori, Joyce and Hanson-Kahn, Andrea and Bernstein, Jonathan A and Carr, Lucinda and D{\textquoteright}Arco, Felice and Miyana, Kaori and Okazaki, Tetsuya and Saito, Yoshiaki and Sasaki, Masayuki and Das, Soma and Wheeler, Marsha M and Bamshad, Michael J and Nickerson, Deborah A and Engle, Elizabeth C and Verheijen, Frans W and Doherty, Dan and Mancini, Grazia M S} }