@article {857, title = {Heterozygous Gene Deficiency and Risk of Coronary Artery Disease.}, journal = {Circ Genom Precis Med}, volume = {13}, year = {2020}, month = {2020 10}, pages = {417-423}, abstract = {

BACKGROUND: Familial sitosterolemia is a rare Mendelian disorder characterized by hyperabsorption and decreased biliary excretion of dietary sterols. Affected individuals typically have complete genetic deficiency-homozygous loss-of-function (LoF) variants-in the or genes and have substantially elevated plasma sitosterol and LDL (low-density lipoprotein) cholesterol (LDL-C) levels. The impact of partial genetic deficiency of or -as occurs in heterozygous carriers of LoF variants-on LDL-C and risk of coronary artery disease (CAD) has remained uncertain.

METHODS: We first recruited 9 sitosterolemia families, identified causative LoF variants in or , and evaluated the associations of these or LoF variants with plasma phytosterols and lipid levels. We next assessed for LoF variants in or in CAD cases (n=29 321) versus controls (n=357 326). We tested the association of rare LoF variants in or with blood lipids and risk for CAD. Rare LoF variants were defined as protein-truncating variants with minor allele frequency <0.1\% in or .

RESULTS: In sitosterolemia families, 7 pedigrees harbored causative LoF variants in and 2 pedigrees in . Homozygous LoF variants in either or led to marked elevations in sitosterol and LDL-C. Of those sitosterolemia families, heterozygous carriers of LoF variants exhibited increased sitosterol and LDL-C levels compared with noncarriers. Within large-scale CAD case-control cohorts, prevalence of rare LoF variants in and in was ≈0.1\% each. heterozygous LoF variant carriers had significantly elevated LDL-C levels (25 mg/dL [95\% CI, 14-35]; =1.1{\texttimes}10) and were at 2-fold increased risk of CAD (odds ratio, 2.06 [95\% CI, 1.27-3.35]; =0.004). By contrast, heterozygous LoF carrier status was not associated with increased LDL-C or risk of CAD.

CONCLUSIONS: Although familial sitosterolemia is traditionally considered as a recessive disorder, we observed that heterozygous carriers of an LoF variant in had significantly increased sitosterol and LDL-C levels and a 2-fold increase in risk of CAD.

}, issn = {2574-8300}, doi = {10.1161/CIRCGEN.119.002871}, author = {Nomura, Akihiro and Emdin, Connor A and Won, Hong Hee and Peloso, Gina M and Natarajan, Pradeep and Ardissino, Diego and Danesh, John and Schunkert, Heribert and Correa, Adolfo and Bown, Matthew J and Samani, Nilesh J and Erdmann, Jeanette and McPherson, Ruth and Watkins, Hugh and Saleheen, Danish and Elosua, Roberto and Kawashiri, Masa-Aki and Tada, Hayato and Gupta, Namrata and Shah, Svati H and Rader, Daniel J and Gabriel, Stacey and Khera, Amit V and Kathiresan, Sekar} } @article {928, title = {Novel congenital disorder of O-linked glycosylation caused by GALNT2 loss of function.}, journal = {Brain}, volume = {143}, year = {2020}, month = {2020 04 01}, pages = {1114-1126}, abstract = {

Congenital disorders of glycosylation are a growing group of rare genetic disorders caused by deficient protein and lipid glycosylation. Here, we report the clinical, biochemical, and molecular features of seven patients from four families with GALNT2-congenital disorder of glycosylation (GALNT2-CDG), an O-linked glycosylation disorder. GALNT2 encodes the Golgi-localized polypeptide N-acetyl-d-galactosamine-transferase 2 isoenzyme. GALNT2 is widely expressed in most cell types and directs initiation of mucin-type protein O-glycosylation. All patients showed loss of O-glycosylation of apolipoprotein C-III, a non-redundant substrate for GALNT2. Patients with GALNT2-CDG generally exhibit a syndrome characterized by global developmental delay, intellectual disability with language deficit, autistic features, behavioural abnormalities, epilepsy, chronic insomnia, white matter changes on brain MRI, dysmorphic features, decreased stature, and decreased high density lipoprotein cholesterol levels. Rodent (mouse and rat) models of GALNT2-CDG recapitulated much of the human phenotype, including poor growth and neurodevelopmental abnormalities. In behavioural studies, GALNT2-CDG mice demonstrated cerebellar motor deficits, decreased sociability, and impaired sensory integration and processing. The multisystem nature of phenotypes in patients and rodent models of GALNT2-CDG suggest that there are multiple non-redundant protein substrates of GALNT2 in various tissues, including brain, which are critical to normal growth and development.

}, keywords = {Adolescent, Animals, Apolipoprotein C-III, Child, Child, Preschool, Developmental Disabilities, Female, Glycosylation, Humans, Loss of Function Mutation, Male, Mice, N-Acetylgalactosaminyltransferases, Pedigree, Rats, Young Adult}, issn = {1460-2156}, doi = {10.1093/brain/awaa063}, author = {Zilmer, Monica and Edmondson, Andrew C and Khetarpal, Sumeet A and Alesi, Viola and Zaki, MAH S and Rostasy, Kevin and Madsen, Camilla G and Lepri, Francesca R and Sinibaldi, Lorenzo and Cusmai, Raffaella and Novelli, Antonio and Issa, Mahmoud Y and Fenger, Christina D and Abou Jamra, Rami and Reutter, Heiko and Briuglia, Silvana and Agolini, Emanuele and Hansen, Lars and Pet{\"a}j{\"a}-Repo, Ulla E and Hintze, John and Raymond, Kimiyo M and Liedtke, Kristen and Stanley, Valentina and Musaev, Damir and Gleeson, Joseph G and Vitali, Cecilia and O{\textquoteright}Brien, W Timothy and Gardella, Elena and Rubboli, Guido and Rader, Daniel J and Schjoldager, Katrine T and M{\o}ller, Rikke S} }