Congenital glycosylation disorder type Ⅱm caused by SLC35A2 mutations: a report of 3 cases and literature review / 中华神经科杂志

Objective:To summarize the clinical manifestations, gene variations, diagnosis and treatment of 3 cases with SLC35A2 variations characterized by congenital glycosylation disorder Ⅱm (CDG Ⅱm). Methods:A total of 3 patients admitted to the Department of Pediatrics of Xiangya Hospital of Central South University in China from 2018 to 2020 were examined in detail. The studies till January 2022 were searched with key words of "congenital disorders of glycosylation Ⅱm", " SLC35A2" and "CDG Ⅱm" in both English and Chinese in the databases of China National Knowledge Infrast Ructure (CNKI), Wanfang, Online Mendelian Inheritance in Man and PubMed, and the clinical manifestations, genetic variation, treatments and prognosis of patients with SLC35A2 mutation were summarized. Results:The patients all presented with intractable infantile spasm and global developmental delay, onset in infancy. A variety of antiepileptic treatments had temporary and partial efficacy. Otherwise, proband 2 and 3 presented with abnormal glutamic-pyruvic transaminase and increased platelets. Funduscopy showed dysplasia of the retinal pigment epithelium in both eyes, and they both received D-galactose treatment. A total of 22 relevant case reports, including 99 patients, were collected. The 99 patients all were heterozygous mutations, and a total of 75 different variation sites were reported. The clinical manifestations were characterized by global developmental delay or mental retardation ( n=89), epileptic seizure ( n=75), hypotonia ( n=57), facial deformity ( n=57), skeletal abnormality ( n=50), visual impairment ( n=42), elevated glutamic-pyruvic transaminase ( n=31), gastrointestinal symptoms ( n=28), skin deformity ( n=26), microcephaly ( n=23) and congenital heart disease ( n=12). Craniocerebral magnetic resonance imaging may be normal in the early stage. With age, magnetic resonance imaging may show abnormal white matter signals, brain atrophy, dysplasia of corpus callosum, delayed myelination, enlargement of lateral ventricle, brain stem atrophy and so on. Studies have shown that galactose treatment may be effective. Conclusions:SLC35A2 variants lead to CDG Ⅱm, whose clinical manifestations mainly include epileptic encephalopathy and global developmental delay. Multiple antiepileptic therapies can temporarily or partially control seizures, while oral galactose may improve the clinical symptoms, showing its prospect as a dietary therapy.

Clinical and genetic features of a patient with COG5-CDG caused by COG5 gene variation / 中华检验医学杂志

The patient in this study was a 3 years 8 month old boy. The patient presented with facial dysmorphism including wide eye distance and flat nose. The major clinical manifestations were poor response, backward language and motor development; and his fingers cannot be bent. Moreover, the patient′s hands were also uncoordinated. In addition the patient suffered from congenital myopia and nystagmus; and the teeth were fall off easily. The abnormal reproductive system was characterized by small penis and small testicle. No obvious abnormality was found in liver and kidney function and serum immunoglobulin level through laboratory biochemical test. The results of the spine X-Ray examination indicates scoliosis. Results from brain MRI showed cerebellar dysplasia. Compound heterozygous variants in COG5 gene (c.1039C>T and c.928+3A>G), each inheranted from his parents were found in this patient by high-throughput sequencing and Sanger sequencing. After a clear diagnosis, the patient received language rehabilitation training and motor rehabilitation training. In this study, we found two new variants in COG5 gene and increased the mutation spectrum of this gene.

Transferrin isoelectric focusing for the investigation of congenital disorders of glycosylation: analysis of a ten-year experience in a Brazilian center / Isoeletrofocalização da transferrina para investigação das doenças congênitasda glicosilação: análise de dez anos de experiência de um centro brasileiro

Abstract Objectives: To characterize cases of suspected congenital disorders of glycosylation (CDG) investigated in a laboratory in southern Brazil using the transferrin isoelectric focusing TfIEF test from 2008 to 2017. Method: Observational, cross-sectional, retrospective study. The laboratory records of 1,546 individuals (median age = 36 months, 25-75 IQR = 10-108; males = 810) submitted to the TfIEF test during the period were reviewed. Results: Fifty-one individuals (3%) had an altered TfIEF pattern (5 ± 2.8 cases/year; median age = 24 months, 25-75 IQR = 11-57 months; males = 27, 53%). For 14 of them, data on diagnosis conclusion were available (classic galactosemia = 4; hereditary fructose intolerance = 4; peroxisomal diseases = 2; PMM2-CDG = 2; MPDU1-CDG = 1; SLC35A2-CDG = 1).Comparing the cases with the normal and altered TfIEF patterns, there was a higher prevalence of altered cases in the age group from 11 months to 3 years. There was an increase in the likelihood of change in TfIEF, especially in the presence of inverted nipples or liver disease. Conclusions: The data suggest that the investigation of a case with suspected CDG is a complex problem, being aggravated by the existence of other IEMs (inborn errors of metabolism) associated with altered TfIEF pattern and lack of access to confirmatory tests. The presence of inverted nipples and liver disease, especially in individuals aged 11 months to 3 years, should suggest the need for TfIEF investigation.

Resumo Objetivos: Caracterizar os casos com suspeita de CDG investigados em laboratório do sul do Brasil pelo exame de IEFTF de 2008 a 2017. Metodologia: Estudo observacional, transversal, retrospectivo. Foram revisadas as fichas laboratoriais de 1.546 indivíduos (mediana de idade = 36 meses, IQ 25-75 = 10-108; sexo masculino = 810) que fizeram o exame de IEFTF no período. Resultados: Cinquenta e um indivíduos (3%) apresentaram padrão alterado na IEFTF (5 ± 2,8 casos/ano; mediana de idade = 24 meses, IQ 25-75 = 11-57 meses; sexo masculino = 27, 53%). Para 14 deles, estavam disponíveis dados sobre a conclusão do diagnóstico (galactosemia clássica = 4; intolerância hereditária à frutose = 4; doenças peroxissomais = 2; PMM2-CDG = 2; MPDU1-CDG = 1; SLC35A2-CDG = 1). Comparando os casos com padrão normal e alterado na IEFTF, houve maior prevalência de casos alterados na faixa etária de 11 meses a 3 anos. Verificou-se um aumento na probabilidade de alteração na IEFTF principalmente na presença de mamilos invertidos ou de hepatopatia. Conclusões: Os nossos dados sugerem que a investigação de um caso com suspeita de CDG é complexa, é agravada pela existência de outros EIM associados a padrão alterado na IEFTF e pela falta de acesso a exames confirmatórios. A presença principalmente de mamilos invertidos e de hepatopatia em indivíduos na faixa etária de 11 meses a 3 anos deve sugerir a necessidade de investigação por IEFTF.

Congenital disorders of glycosylation and liver diseases / 临床肝胆病杂志

Congenital disorders of glycosylation (CDGs) is a group of inherited metabolic diseases caused by abnormal glycosylation of protein or lipids, and the number of CDGs are increasing rapidly in recent years. With the advent and popularization of next-generation sequencing, more and more disorders associated with glycosylation-related gene mutations have been discovered. Synthesis of glycoproteins and glycolipids is one of the major roles of the liver, and many CDGs affect hepatobiliary structure or function and may lead to fatty liver disease, liver fibrosis, and ductal plate malformation. This article reports the latest advances in the pathogenesis, diagnosis, and treatment of CDGs and related liver diseases.

Congenital disorder of glycosylation type Ⅰg: a case report and literature review / 中国新生儿科杂志

Objective To study the clinical features,diagnosis,genetic characteristics and treatment of congenital disorder of glycosylation type Ⅰg (CDG-Ⅰg) and to raise the awareness of CDG-Ⅰg among the clinicians.Method The data of one child with CDG-Ⅰg admitted to Shanghai Children's Medical Center affiliated to Shanghai Jiaotong University School of Medicine was studied retrospectively.Literatures were retrieved with key words including "congenital glycosylation disorder Ⅰg","ALG12","congenital glycosylation defect Ⅰg","CDG-Ⅰg" and "congenital disorder" in the Chinese knowledge network,VP database,Wanfang database,Biomedicine,PubMed and the Web of Science database from data established until January 2018.We summarized the clinical and genetic characteristics of CDG-Ⅰg.Result An one-day-old male infant admitted to the Hospital due to "poor response with hypoglycemia" manifested with facial deformity,hypotonia,inverted nipples,micropenis and undescended testes.He had intermittent hypoglycemia and recurrent infection,treated with antimicrobials,glucose rehydration and hormone therapy.Serum insulin,growth hormone level,blood and urine metabolic screening were normal.The patient was compound heterozygous for ALG12 mutations,c.432C ＞ A,p.Cys144 * and c.904T ＞ C,p.Tyr302His,each of his parents carried a pathogenic mutation.The patient died in follow-up for unknown reasons.No reported cases of CDG-Ⅰg from China have so far been reported yet.We reviewed the other 8 cases CDG-Ⅰg (4 males and 4 females) born in foreign countries,5 of them with neonatal onset.Common clinical manifestaions include facial deformity,hypotonia,hypogenitalism,coagulopathy,hypoimmunity,recurrent infection,electroyte imbalance etc.The ALG12 gene has 11 mutation sites.Conclusion CDG-Ⅰg is a rare autosomal recessive disorder.Most reported patients had onset in neonatal period.It seems that the association of facial deformity,psychomotor retardation,hypotonia,coagulopathy,male hypogenitalism and hypoglycemia might be a clue to the diagnosis of CDG-Ⅰg.Gene detection of ALG12 can confirm the diagnosis.This disorder has no specific treatment yet.

Progress in congenital disorders of glycosylation / 中国病理生理杂志

Congenital disorders of glycosylation(CDG) are a rapidly growing group of genetic diseases that are due to defects in the synthesis of glycans and in the attachment of glycans to other compounds. Most CDG are multisystemic diseases often involving severe psychomotor retardation. The CDG causing sialic acid deficiency of N-glycans can be diagnosed by isoelectric focusing of serum transferrin. Glycan structural analysis, yeast genetics and knockout animal models are essential tools in the elucidation of novel CDG. In this review, we focus on the current knowledge of the pathogenesis and identification of nine primary glycosylation diseases.