@ARTICLE{10.3389/fnhum.2013.00858, AUTHOR={Spilioti, Martha and Evangeliou, Athanasios and Tramma, Despoina and Theodoridou, Zoe and Metaxas, Spyridon and Michailidi, Eleni and Bonti, Eleni and Frysira, Helen and Haidopoulou, Katerina and Asprangathou, Despoina and Tsalkidis, Aggelos and Kardaras, Panagiotis and Wevers, Ron and Jakobs, Cornelis and Gibson, Michael}, TITLE={Evidence for treatable inborn errors of metabolism in a cohort of 187 Greek patients with autism spectrum disorder (ASD)}, JOURNAL={Frontiers in Human Neuroscience}, VOLUME={7}, YEAR={2013}, URL={https://www.frontiersin.org/articles/10.3389/fnhum.2013.00858}, DOI={10.3389/fnhum.2013.00858}, ISSN={1662-5161}, ABSTRACT={We screened for the presence of inborn errors of metabolism (IEM) in 187 children (105 males; 82 females, ages 4–14 years old) who presented with confirmed features of autism spectrum disorder (ASD). Twelve patients (7%) manifested increased 3-hydroxyisovaleric acid (3-OH-IVA) excretion in urine, and minor to significant improvement in autistic features was observed in seven patients following supplementation with biotin. Five diagnoses included: Lesch Nyhan syndrome (2), succinic semialdehyde dehydrogenase (SSADH) deficiency (2), and phenylketonuria (1) (2.7%). Additional metabolic disturbances suggestive of IEMs included two patients whose increased urine 3-OH-IVA was accompanied by elevated methylcitrate and lactate in sera, and 30 patients that showed abnormal glucose-loading tests. In the latter group, 16/30 patients manifested increased sera beta hydroxybutyrate (b-OH-b) production and 18/30 had a paradoxical increase of sera lactate. Six patients with elevated b-OH-b in sera showed improved autistic features following implementation of a ketogenic diet (KD). Five patients showed decreased serum ketone body production with glucose loading. Twelve of 187 patients demonstrated non-specific MRI pathology, while 25/187 had abnormal electroencephalogram (EEG) findings. Finally, family history was positive for 22/187 patients (1st or 2nd degree relative with comparable symptomatology) and consanguinity was documented for 12/187 patients. Our data provide evidence for a new biomarker (3-OH-IVA) and novel treatment approaches in ASD patients. Concise 1 sentence take-home message: Detailed metabolic screening in a Greek cohort of ASD patients revealed biomarkers (urine 3-hydroxyisovaleric acid and serum b-OH-b) in 7% (13/187) of patients for whom biotin supplementation or institution of a KD resulted in mild to significant clinical improvement in autistic features.} }