TY - JOUR
T1 - Clinical, neuroradiological, and biochemical features of SLC35A2-CDG patients
AU - EPGEN Study
AU - Vals, Mari-Anne
AU - Ashikov, Angel
AU - Ilves, Pilvi
AU - Loorits, Dagmar
AU - Zeng, Qiang
AU - Barone, Rita
AU - Huijben, Karin
AU - Sykut-Cegielska, Jolanta
AU - Diogo, Luísa
AU - Elias, Abdallah F.
AU - Greenwood, Robert S.
AU - Grunewald, Stephanie
AU - van Hasselt, Peter M.
AU - van de Kamp, Jiddeke M.
AU - Mancini, Grazia
AU - Okninska, Agnieszka
AU - Pajusalu, Sander
AU - Rudd, Pauline M.
AU - Rustad, Cecilie F.
AU - Salvarinova, Ramona
AU - de Vries, Bert B. A.
AU - Wolf, Nicole I.
AU - Lefeber, Dirk J.
AU - Õunap, Katrin
PY - 2019/5/1
Y1 - 2019/5/1
N2 - SLC35A2-CDG is caused by mutations in the X-linked SLC35A2 gene encoding the UDP-galactose transporter. SLC35A2 mutations lead to hypogalactosylation of N-glycans. SLC35A2-CDG is characterized by severe neurological symptoms and, in many patients, early-onset epileptic encephalopathy. In view of the diagnostic challenges, we studied the clinical, neuroradiological, and biochemical features of 15 patients (11 females and 4 males) with SLC35A2-CDG from various centers. We describe nine novel pathogenic variations in SLC35A2. All affected individuals presented with a global developmental delay, and hypotonia, while 70% were nonambulatory. Epilepsy was present in 80% of the patients, and in EEG hypsarrhythmia and findings consistent with epileptic encephalopathy were frequently seen. The most common brain MRI abnormality was cerebral atrophy with delayed myelination and multifocal inhomogeneous abnormal patchy white matter hyperintensities, which seemed to be nonprogressive. Thin corpus callosum was also common, and all the patients had a corpus callosum shorter than normal for their age. Variable dysmorphic features and growth deficiency were noted. Biochemically, normal mucin type O-glycosylation and lipid glycosylation were found, while transferrin mass spectrometry was found to be more specific in the identification of SLC35A2-CDG, as compared to routine screening tests. Although normal glycosylation studies together with clinical variability and genetic results complicate the diagnosis of SLC35A2-CDG, our data indicate that the combination of these three elements can support the pathogenicity of mutations in SLC35A2.
AB - SLC35A2-CDG is caused by mutations in the X-linked SLC35A2 gene encoding the UDP-galactose transporter. SLC35A2 mutations lead to hypogalactosylation of N-glycans. SLC35A2-CDG is characterized by severe neurological symptoms and, in many patients, early-onset epileptic encephalopathy. In view of the diagnostic challenges, we studied the clinical, neuroradiological, and biochemical features of 15 patients (11 females and 4 males) with SLC35A2-CDG from various centers. We describe nine novel pathogenic variations in SLC35A2. All affected individuals presented with a global developmental delay, and hypotonia, while 70% were nonambulatory. Epilepsy was present in 80% of the patients, and in EEG hypsarrhythmia and findings consistent with epileptic encephalopathy were frequently seen. The most common brain MRI abnormality was cerebral atrophy with delayed myelination and multifocal inhomogeneous abnormal patchy white matter hyperintensities, which seemed to be nonprogressive. Thin corpus callosum was also common, and all the patients had a corpus callosum shorter than normal for their age. Variable dysmorphic features and growth deficiency were noted. Biochemically, normal mucin type O-glycosylation and lipid glycosylation were found, while transferrin mass spectrometry was found to be more specific in the identification of SLC35A2-CDG, as compared to routine screening tests. Although normal glycosylation studies together with clinical variability and genetic results complicate the diagnosis of SLC35A2-CDG, our data indicate that the combination of these three elements can support the pathogenicity of mutations in SLC35A2.
KW - CDG
KW - SLC35A2
KW - congenital glycosylation disorders
KW - epileptic encephalopathy
KW - infantile spasms
UR - https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85064848845&origin=inward
UR - https://www.ncbi.nlm.nih.gov/pubmed/30746764
U2 - https://doi.org/10.1002/jimd.12055
DO - https://doi.org/10.1002/jimd.12055
M3 - Article
C2 - 30746764
SN - 0141-8955
VL - 42
SP - 553
EP - 564
JO - Journal of Inherited Metabolic Disease
JF - Journal of Inherited Metabolic Disease
IS - 3
ER -