Congenital chloride diarrhea (CLD) is an autosomal recessive disorder with the hallmark of persistent watery Cl(-)-rich diarrhea from birth. Mutations in the solute carrier family 26, member 3 (SLC26A3) gene, which encodes a coupled Cl-/HCO3- exchanger in the ileum and colon, are known to cause CLD. Although there are a few reports of CLD patients in Korea, none of these had been confirmed by genetic analysis. Here, we describe the case of a Korean infant with clinical features of CLD. Using direct sequencing analysis, we identified 2 sequence variants: a missense variant of unknown significance (c.525G>C; p.Arg175 Ser) and a splicing mutation (c.2063-1G>T) in the SLC26A3 gene; these had been inherited from the father and mother, respectively. Whilst CLD is rare, its main symptom, diarrhea, is very common in infants. Hence, the diagnosis of CLD can prove difficult. Mutational analysis of the SLC26A3 gene should be considered as a viable method to confirm a diagnosis of CLD in Korean infants with persistent diarrhea.
Asian Continental Ancestry Group/*genetics ; Chloride-Bicarbonate Antiporters/*genetics ; DNA Mutational Analysis ; Diarrhea/*congenital/diagnosis/genetics/radiography ; Heterozygote ; Humans ; Infant ; Male ; Metabolism, Inborn Errors/*diagnosis/genetics/radiography ; Mutation ; Mutation, Missense ; RNA Splicing ; Republic of Korea ; Ultrasonography, Prenatal

Amino Acid Metabolism, Inborn Errors ; diagnosis ; genetics ; therapy ; Brain ; diagnostic imaging ; metabolism ; pathology ; Brain Diseases, Metabolic ; diagnosis ; genetics ; therapy ; Child, Preschool ; Diagnosis, Differential ; Glutarates ; metabolism ; Glutaryl-CoA Dehydrogenase ; deficiency ; genetics ; Humans ; Infant ; Infant, Newborn ; Lysine ; metabolism ; Magnetic Resonance Imaging ; Multiple Acyl Coenzyme A Dehydrogenase Deficiency ; diagnosis ; genetics ; therapy ; Mutation ; Neonatal Screening ; methods ; Radiography

OBJECTIVETo analyze the clinical and SLC2A1 gene mutation characteristics of glucose transporter type 1 deficiency syndrome.

METHODThe detailed clinical manifestations of six cases were recorded. The laboratory tests including EEG, MRI, blood chemistry, and lumbar puncture were performed. SLC2A1 gene mutations were analyzed by PCR, DNA sequencing and multiplex ligation-dependent probe amplification (MLPA).

RESULTPatient 1, 2 and 3 had classical clinical symptoms including infantile onset seizures, development delay. Patient 4, 5 and 6 had non-classical clinical symptoms including paroxysmal behavior disturbance, weakness, ataxia, lethargy, especially after fasting or exercise, without severe seizures. The plasma glucose levels were normal. The CSF glucose levels decreased in all the six cases, ranged from 1.10 mmol/L to 2.45 mmol/L, the mean level was 1.68 mmol/L. The CSF glucose/plasma glucose ratios decreased, ranged from 0.16 to 0.51, the mean ratio was 0.34. Four patients had normal EEG. Two patients had focal and diffuse epileptiform discharge, and one of them also had paroxysmal occipital or generalized high-amplitude slow waves during awake and sleep time. MRI abnormalities were found in three patients, patient 1 with mild brain atrophy, patient 3 with bilateral ventricle plump, and patient 4 with high signals in T2 in the frontal and occipital white matter, interpreted as hypomyelination. SLC2A1 gene mutations were found in six cases. Patient 1 has large scale deletion in exon 2. In patient 2 to 6, the mutations were c.741 G>A (E247K), 599delA, 761delA, c.1148 C>A (P383H), c.1198 C>T (R400C) respectively. Two patients were treated with ketogenic diet. The seizures disappeared and development became normal. Three patients responded to frequent meals with snacks. One patient refused any treatments, the symptoms continued to exist.

CONCLUSIONThe clinical manifestations of glucose transporter type 1 deficiency syndrome are varied. The common symptoms included infantile onset seizures and various paroxysmal events. These neurologic symptoms generally fluctuated and were influenced by factors such as fasting or fatigue. This feature could be a very important clue for the diagnosis of GLUT1-DS. Lumbar puncture is recommended in patients with episodic CNS symptoms especially after fasting. GLUT1-DS is a treatable neurometabolic disorder, early diagnosis and treatment may improve the prognosis of the patients.

Biomarkers ; analysis ; Brain ; diagnostic imaging ; pathology ; Carbohydrate Metabolism, Inborn Errors ; diagnosis ; genetics ; therapy ; Child ; Child, Preschool ; DNA Mutational Analysis ; Diet, Ketogenic ; Electroencephalography ; Epilepsy ; diagnosis ; genetics ; therapy ; Female ; Follow-Up Studies ; Glucose Transporter Type 1 ; genetics ; Humans ; Infant ; Magnetic Resonance Imaging ; Male ; Monosaccharide Transport Proteins ; deficiency ; genetics ; Movement Disorders ; diagnosis ; genetics ; therapy ; Mutation ; genetics ; Radiography