The purpose of this study is to identify metabolitic signatures in blood plasma and/or urine using a panel of biomarker metabolites that differentiate children with autism spectrum disorder (ASD) from children with delayed development (DD) and/or typical development (TD), to develop an algorithm that maximizes sensitivity and specificity of the biomarker profile, and to evaluate the overall algorithm as a diagnostic tool.
A secondary objective is to define metabolites capable of classifying subtypes of ASD that may increase understanding of the metabolic basis of the condition, as well as inform on personalized therapy.
The population targeted for this study includes children aged 18 months to 48 months, diagnosed with ASD or DD using behavioral criteria, and TD children, identified as having no indications of ASD or DD using behavioral criteria. The original target size for the study was 1500 subjects divided equally between the three groups. The targeted male:female ratio is 4:1 in all three groups. During the study, it was determined that biomarkers capable of identifying ASD subjects could be obtained using a total of 1100 subjects divided with 58% ASD, 25%TD, and 17% DD. If the diagnostic biomarkers identified in the study do not perform well in females during the biomarker discovery phase, the study may be expanded to recruit more females to examine the possibility of a female-specific diagnostic test.
Subjects will be qualified for entry into the study and will be invited to participate. On the first study day, subjects' parents will sign an informed consent form and will be asked questions on the mother's pregnancy and of both parents' medical history. A complete medical history, a physical examination, and information needed to obtain a diagnosis of ASD, DD, or TD will be obtained on the study subject. If possible, a urine sample will be collected during the visit. Up to four tubes of blood (\<25 mLs total) will be drawn at the clinic during the visit or within 14 days following this initial visit. An overnight fast is required prior to the visit where blood will be taken from the subject. A subset of the subjects will be asked to return to the clinic 30-60 days later to obtain a replicate metabolic profile.
The study will be divided into a biomarker discovery/method development phase followed by a validation phase of the analytical methods and algorithm that will be used in the clinical test.
The subjects will be randomized and divided equally between a discovery/training set and a validation set. The training set will be used for discovery of the biomarkers and development of the analytical methods intended for the diagnostic test. The validation sample set will be used to evaluate performance of the final clinical methods and algorithms.
Consent will also be sought from all subjects for follow-up contact up to 5 years following enrollment of the last subject enrolled to determine the accuracy of the original behavioral diagnosis over time. Subjects chosen for follow-up will be identified based on the strength of the diagnosis from the behavioral scores and physician assessments as well as the biomarker profiles observed in individuals.
