TY - JOUR
T1 - Stroke-like episodes and cerebellar syndrome in phosphomannomutase deficiency (PMM2-CDG): Evidence for hypoglycosylation-driven channelopathy
AU - Izquierdo-Serra, Mercè
AU - Martínez-Monseny, Antonio F.
AU - López, Laura
AU - Carrillo-García, Julia
AU - Edo, Albert
AU - Ortigoza-Escobar, Juan Darío
AU - García, Óscar
AU - Cancho-Candela, Ramón
AU - Carrasco-Marina, M. Llanos
AU - Gutiérrez-Solana, Luis G.
AU - Cuadras, Daniel
AU - Muchart, Jordi
AU - Montero, Raquel
AU - Artuch, Rafael
AU - Pérez-Cerdá, Celia
AU - Pérez, Belén
AU - Pérez-Dueñas, Belén
AU - Macaya, Alfons
AU - Fernández-Fernández, José M.
AU - Serrano, Mercedes
PY - 2018/2/22
Y1 - 2018/2/22
N2 - © 2018 by the authors. Licensee MDPI, Basel, Switzerland. Stroke-like episodes (SLE) occur in phosphomannomutase deficiency (PMM2-CDG), and may complicate the course of channelopathies related to Familial Hemiplegic Migraine (FHM) caused by mutations in CACNA1A (encoding CaV2.1 channel). The underlying pathomechanisms are unknown. We analyze clinical variables to detect risk factors for SLE in a series of 43 PMM2-CDG patients. We explore the hypothesis of abnormal CaV2.1 function due to aberrant N-glycosylation as a potential novel pathomechanism of SLE and ataxia in PMM2-CDG by using whole-cell patch-clamp, N-glycosylation blockade and mutagenesis. Nine SLE were identified. Neuroimages showed no signs of stroke. Comparison of characteristics between SLE positive versus negative patients’ group showed no differences. Acute and chronic phenotypes of patients with PMM2-CDG or CACNA1A channelopathies show similarities. Hypoglycosylation of both CaV2.1 subunits (α1A and α2α) induced gain-of-function effects on channel gating that mirrored those reported for pathogenic CACNA1A mutations linked to FHM and ataxia. Unoccupied N-glycosylation site N283 at α1A contributes to a gain-of-function by lessening CaV2.1 inactivation. Hypoglycosylation of the α2δ subunit also participates in the gain-of-function effect by promoting voltage-dependent opening of the CaV2.1 channel. CaV2.1 hypoglycosylation may cause ataxia and SLEs in PMM2-CDG patients. Aberrant CaV2.1 N-glycosylation as a novel pathomechanism in PMM2-CDG opens new therapeutic possibilities.
AB - © 2018 by the authors. Licensee MDPI, Basel, Switzerland. Stroke-like episodes (SLE) occur in phosphomannomutase deficiency (PMM2-CDG), and may complicate the course of channelopathies related to Familial Hemiplegic Migraine (FHM) caused by mutations in CACNA1A (encoding CaV2.1 channel). The underlying pathomechanisms are unknown. We analyze clinical variables to detect risk factors for SLE in a series of 43 PMM2-CDG patients. We explore the hypothesis of abnormal CaV2.1 function due to aberrant N-glycosylation as a potential novel pathomechanism of SLE and ataxia in PMM2-CDG by using whole-cell patch-clamp, N-glycosylation blockade and mutagenesis. Nine SLE were identified. Neuroimages showed no signs of stroke. Comparison of characteristics between SLE positive versus negative patients’ group showed no differences. Acute and chronic phenotypes of patients with PMM2-CDG or CACNA1A channelopathies show similarities. Hypoglycosylation of both CaV2.1 subunits (α1A and α2α) induced gain-of-function effects on channel gating that mirrored those reported for pathogenic CACNA1A mutations linked to FHM and ataxia. Unoccupied N-glycosylation site N283 at α1A contributes to a gain-of-function by lessening CaV2.1 inactivation. Hypoglycosylation of the α2δ subunit also participates in the gain-of-function effect by promoting voltage-dependent opening of the CaV2.1 channel. CaV2.1 hypoglycosylation may cause ataxia and SLEs in PMM2-CDG patients. Aberrant CaV2.1 N-glycosylation as a novel pathomechanism in PMM2-CDG opens new therapeutic possibilities.
KW - Ataxia
KW - CaV2.1 voltage-gated calcium channel
KW - Cerebellum
KW - Congenital disorders of glycosylation
KW - Magentic resonance Imaging (MRI)
KW - Stroke-like
U2 - 10.3390/ijms19020619
DO - 10.3390/ijms19020619
M3 - Article
VL - 19
IS - 2
M1 - 619
ER -