@article {708, title = {Genetic and molecular mechanism for distinct clinical phenotypes conveyed by allelic truncating mutations implicated in FBN1.}, journal = {Mol Genet Genomic Med}, volume = {8}, year = {2020}, month = {2020 01}, pages = {e1023}, abstract = {

BACKGROUND: The molecular and genetic mechanisms by which different single nucleotide variant alleles in specific genes, or at the same genetic locus, cause distinct disease phenotypes often remain unclear. Allelic truncating mutations of FBN1 could cause either classical Marfan syndrome (MFS) or a more complicated phenotype associated with Marfanoid-progeroid-lipodystrophy syndrome (MPLS).

METHODS: We investigated a small cohort, encompassing two classical MFS and one MPLS subjects~from China, whose clinical presentation included scoliosis potentially requiring surgical intervention. Targeted next generation sequencing was performed on all the participants. We analyzed the molecular diagnosis, clinical features, and the potential molecular mechanism involved in the MPLS subject in our cohort.

RESULTS: We report a novel de novo FBN1 mutation for the first Chinese subject~with MPLS, a more complicated fibrillinopathy, and two subjects~with more classical MFS. We further predict that the MPLS truncating mutation, and others previously reported, is prone to escape the nonsense-mediated decay (NMD), while MFS mutations are predicted to be subjected to NMD. Also, the MPLS mutation occurs within the glucogenic hormone asprosin domain of FBN1. In vitro experiments showed that the single MPLS mutation p.Glu2759Cysfs*9 appears to perturb proper FBN1 protein aggregation as compared with the~classical MFS mutation p.Tyr2596Thrfs*86. Both mutations appear to upregulate SMAD2 phosphorylation in vitro.

CONCLUSION: We provide direct evidence that a dominant-negative interaction of FBN1 potentially explains the complex MPLS phenotypes through genetic and functional analysis. Our study expands the mutation spectrum of FBN1 and highlights the potential molecular mechanism for MPLS.

}, keywords = {Adolescent, Adult, Child, Female, Fibrillin-1, HEK293 Cells, Humans, Lipodystrophy, Marfan Syndrome, Mutation, Phenotype, Progeria, Protein Domains, Smad2 Protein}, issn = {2324-9269}, doi = {10.1002/mgg3.1023}, author = {Lin, Mao and Liu, Zhenlei and Liu, Gang and Zhao, Sen and Li, Chao and Chen, Weisheng and Coban Akdemir, Zeynep and Lin, Jiachen and Song, Xiaofei and Wang, Shengru and Xu, Qiming and Zhao, Yanxue and Wang, Lianlei and Zhang, Yuanqiang and Yan, Zihui and Liu, Sen and Liu, Jiaqi and Chen, Yixin and Zuo, Yuzhi and Yang, Xu and Sun, Tianshu and Yang, Xin-Zhuang and Niu, Yuchen and Li, Xiaoxin and You, Wesley and Qiu, Bintao and Ding, Chen and Liu, Pengfei and Zhang, Shuyang and Carvalho, Claudia M B and Posey, Jennifer E and Qiu, Guixing and Lupski, James R and Wu, Zhihong and Zhang, Jianguo and Wu, Nan} } @article {548, title = {Analyses of LMNA-negative juvenile progeroid cases confirms biallelic POLR3A mutations in Wiedemann-Rautenstrauch-like syndrome and expands the phenotypic spectrum of PYCR1 mutations.}, journal = {Hum Genet}, volume = {137}, year = {2018}, month = {2018 Dec}, pages = {921-939}, abstract = {

Juvenile segmental progeroid syndromes are rare, heterogeneous disorders characterized by signs of premature aging affecting more than one tissue or organ starting in childhood. Hutchinson-Gilford progeria syndrome (HGPS), caused by a recurrent de novo synonymous LMNA mutation resulting in aberrant splicing and generation of a mutant product called progerin, is a prototypical example of such disorders. Here, we performed a joint collaborative study using massively parallel sequencing and targeted Sanger sequencing, aimed at delineating the underlying genetic cause of 14 previously undiagnosed, clinically heterogeneous, non-LMNA-associated juvenile progeroid patients. The molecular diagnosis was achieved in 11 of 14 cases (~ 79\%). Furthermore, we firmly establish biallelic mutations in POLR3A as the genetic cause of a recognizable, neonatal, Wiedemann-Rautenstrauch-like progeroid syndrome. Thus, we suggest that POLR3A mutations are causal for a portion of under-diagnosed early-onset segmental progeroid syndromes. We additionally expand the clinical spectrum associated with PYCR1 mutations by showing that they can somewhat resemble HGPS in the first year of life. Moreover, our results lead to clinical reclassification in one single case. Our data emphasize the complex genetic and clinical heterogeneity underlying progeroid disorders.

}, keywords = {Adolescent, Alternative Splicing, Child, Female, Fetal Growth Retardation, Genetic Predisposition to Disease, Humans, Infant, Lamin Type A, Male, Mutation, Phenotype, Progeria, Pyrroline Carboxylate Reductases, RNA Polymerase III}, issn = {1432-1203}, doi = {10.1007/s00439-018-1957-1}, author = {Lessel, Davor and Ozel, Ayse Bilge and Campbell, Susan E and Saadi, Abdelkrim and Arlt, Martin F and McSweeney, Keisha Melodi and Plaiasu, Vasilica and Szakszon, Katalin and Sz{\H o}ll{\H o}s, Anna and Rusu, Cristina and Rojas, Armando J and Lopez-Valdez, Jaime and Thiele, Holger and N{\"u}rnberg, Peter and Nickerson, Deborah A and Bamshad, Michael J and Li, Jun Z and Kubisch, Christian and Glover, Thomas W and Gordon, Leslie B} } @article {66, title = {Asprosin, a Fasting-Induced Glucogenic Protein Hormone.}, journal = {Cell}, volume = {165}, year = {2016}, month = {2016 Apr 21}, pages = {566-79}, abstract = {

Hepatic glucose release into the circulation is vital for brain function and survival during periods of fasting and is modulated by an array of hormones that precisely regulate plasma glucose levels. We have identified a fasting-induced protein hormone that modulates hepatic glucose release. It is the C-terminal cleavage product of profibrillin, and we name it Asprosin. Asprosin is secreted by white adipose, circulates at nanomolar levels, and is recruited to the liver, where it activates the G protein-cAMP-PKA pathway, resulting in rapid glucose release into the circulation. Humans and mice with insulin resistance show pathologically elevated plasma asprosin, and its loss of function via immunologic or genetic means~has a profound glucose- and insulin-lowering effect secondary to reduced hepatic glucose release. Asprosin represents a glucogenic protein hormone, and therapeutically targeting it may be beneficial in type II diabetes and metabolic syndrome.

}, keywords = {Adipose Tissue, White, Amino Acid Sequence, Animals, Antibodies, Circadian Rhythm, Cyclic AMP, Cyclic AMP-Dependent Protein Kinases, Fasting, Female, Fetal Growth Retardation, Glucose, Humans, Insulin, Liver, Male, Mice, Mice, Inbred C57BL, Mice, Obese, Microfilament Proteins, Molecular Sequence Data, Peptide Fragments, Peptide Hormones, Progeria, Recombinant Proteins, Sequence Alignment}, issn = {1097-4172}, doi = {10.1016/j.cell.2016.02.063}, author = {Romere, Chase and Duerrschmid, Clemens and Bournat, Juan and Constable, Petra and Jain, Mahim and Xia, Fan and Saha, Pradip K and Del Solar, Maria and Zhu, Bokai and York, Brian and Sarkar, Poonam and Rendon, David A and Gaber, M Waleed and LeMaire, Scott A and Coselli, Joseph S and Milewicz, Dianna M and Sutton, V Reid and Butte, Nancy F and Moore, David D and Chopra, Atul R} }