Inborn Errors of Metabolism Associated With Autism Among Children: A Multicenter Study from Iran

Objective: This study aimed to find the common inborn errors of metabolism in Iranian patients with autism spectrum disorder. Methods: In this cross-sectional multicenter study, 105 children and adolescents with autism spectrum disorder from six centers in different cities of Iran were enrolled between August, 2019 and October, 2020. Metabolic screening, including measuring plasma levels of amino acids, acylcarnitines, creatine, and guanidinoacetate, and urinary levels of organic acids, purines, and pyrimidines was performed. Other data, including age, parental consanguinity, history of seizure, developmental mile-stones, and physical examination, were also recorded. Results: An inborn error of metabolism was found in 13 (12.4%) patients. Five patients (4.8%) had cerebral creatine deficiency syndrome, 4 (3.8%) had arginine succinate aciduria, 2- methylbutyryl glycinuria, short-chain acyl-CoA dehydrogenase deficiency, and combined methylmalonic aciduria/malonic aciduria. There was a strong association between positive metabolic evaluation and parental consanguinity, history of seizures, microcephaly, and delayed development. Conclusions: Our results suggest that metabolic screening should be performed in the cases of autism associated with parental consanguinity, developmental delay, and a history of seizures. The assays to be considered as a screening panel include plasma or blood amino acids, acylcarnitines, creatine and guanidinoacetate, and urinary levels of organic acids.

Fanconi-Bickel syndrome versus osteogenesis imperfeeta: An Iranian case with a novel mutation in glucose transporter 2 gene, and review of literature.

Fanconi-Bickel syndrome is an extremely rare hereditary metabolic disease, characterized by hepatomegaly due to glycogen storage, refractory hypophosphatemic rickets, marked growth retardation and proximal renal tubular acidosis. Recurrent bone fractures are one of the hallmark findings. It is a single gene disorder; the responsible gene belongs to the facilitative glucose transporters 2 (GLUT2) family gene or (SLC2A2) mapped to the q26.1-26.3 locus on chromosome 3, and encodes the GLUT protein 2. This protein is expressed in pancreatic ί-cells, hepatocytes, renal tubules, and intestinal mucosa. Several mutations in the GLUT2 gene have been reported in different ethnicities. Herein we report an Iranian girl with a missed diagnosis of osteogenesis imperfecta. She was referred with the history of frequent fractures, and severe motor delay and was suspected to osteogenesis imperfecta. Following the case we detected refractory rickets instead of OI, sever growth failure, proximal renal tubulopathy and RTA, and enlarged kidneys, progressive hepatomegaly, and GSD on liver biopsy. Glucose and galactose tolerance tests confirmed abnormal carbohydrate metabolism. Molecular analysis on GLUT2 gene revealed a homozygous novel mutation in exon 5; it was 15 nucleotide deletion and 7 nucleotide insertion and caused a frame shift mutation, produced a premature truncated protein (P.A229QFsX19). This mutation has not been reported before in the relevant literature.