Fecal microbiota and metabolome of children with autism and pervasive developmental disorder not otherwise specified

Maria De Angelis, Maria Piccolo, Lucia Vannini, Sonya Siragusa, Andrea De Giacomo, Diana Isabella Serrazzanetti, Fernanda Cristofori, Maria Elisabetta Guerzoni, Marco Gobbetti, Ruggiero Francavilla, Maria De Angelis, Maria Piccolo, Lucia Vannini, Sonya Siragusa, Andrea De Giacomo, Diana Isabella Serrazzanetti, Fernanda Cristofori, Maria Elisabetta Guerzoni, Marco Gobbetti, Ruggiero Francavilla

Abstract

This study aimed at investigating the fecal microbiota and metabolome of children with Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS) and autism (AD) in comparison to healthy children (HC). Bacterial tag-encoded FLX-titanium amplicon pyrosequencing (bTEFAP) of the 16S rDNA and 16S rRNA analyses were carried out to determine total bacteria (16S rDNA) and metabolically active bacteria (16S rRNA), respectively. The main bacterial phyla (Firmicutes, Bacteroidetes, Fusobacteria and Verrucomicrobia) significantly (P<0.05) changed among the three groups of children. As estimated by rarefaction, Chao and Shannon diversity index, the highest microbial diversity was found in AD children. Based on 16S-rRNA and culture-dependent data, Faecalibacterium and Ruminococcus were present at the highest level in fecal samples of PDD-NOS and HC children. Caloramator, Sarcina and Clostridium genera were the highest in AD children. Compared to HC, the composition of Lachnospiraceae family also differed in PDD-NOS and, especially, AD children. Except for Eubacterium siraeum, the lowest level of Eubacteriaceae was found on fecal samples of AD children. The level of Bacteroidetes genera and some Alistipes and Akkermansia species were almost the highest in PDD-NOS or AD children as well as almost all the identified Sutterellaceae and Enterobacteriaceae were the highest in AD. Compared to HC children, Bifidobacterium species decreased in AD. As shown by Canonical Discriminant Analysis of Principal Coordinates, the levels of free amino acids and volatile organic compounds of fecal samples were markedly affected in PDD-NOS and, especially, AD children. If the gut microbiota differences among AD and PDD-NOS and HC children are one of the concomitant causes or the consequence of autism, they may have implications regarding specific diagnostic test, and/or for treatment and prevention.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1. Total and active bacteria found…
Figure 1. Total and active bacteria found in feces of children.
Relative abundance (%) of total bacterial composition (16S-rDNA) (A) and metabolic active bacteria (16S-rRNA) (B) at the phylum level found in the fecal samples of Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS), autistic (AD) and healthy (HC) children.
Figure 2. Principal component analysis (PCA) of…
Figure 2. Principal component analysis (PCA) of active bacteria genera found in feces of children.
Score plot of the three principal components (PC) after PCA of the total bacterial genera information (16S-rRNA) for Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS), autistic (AD) and healthy (HC) children. 1-10, number of fecal samples for each group of children.
Figure 3. Permutation analysis of the active…
Figure 3. Permutation analysis of the active bacterial genera found in feces of children.
Metabolically active bacterial genera composition found in Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS), autistic (AD) and healthy (HC) children. Double dendrogram representation of clustering was performed. The genera that showed values ​​less than 0.1% of the total metabolically active bacterial were grouped together on the same phylum (others Actinobacteria, others Bacteroidetes, others Firmicutes, others Proteobacteria). 1-10, number of fecal samples for each group of children.
Figure 4. Fecal levels of free amino…
Figure 4. Fecal levels of free amino acids (FAA) in children.
Concentration (mg/kg) of FAA found in fecal samples of Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS), autistic (AD) and healthy (HC) children. Data are the means of three independent experiments and standard deviations, performed in duplicate (n=6).
Figure 5. Canonical Discriminant Analysis of Principal…
Figure 5. Canonical Discriminant Analysis of Principal Coordinates (CAP) of volatile organic metabolites in feces of children.
Loading coefficient plots of the volatile organic compounds from fecal samples of Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS) (A), autistic (AD) (B) and healthy (HC) children. Compounds significantly associated with the feces of PDD-NOS children (negative axis) or HC children (positive axis) Data are the means of three independent experiments (n = 3).
Figure 6. Principal component analysis (PCA) of…
Figure 6. Principal component analysis (PCA) of volatile organic metabolites found in feces of children.
Score plots of the two principal components (PC) after PCA of volatile organic metabolites found in fecal samples of Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS), autistic (AD) and healthy (HC) children. All the variables used were listed in Table S1.

References

    1. APA (1994) Diagnostic and statistical manual of mental disorders. 4th edn DC: American: Psychiatric Association; : Washington
    1. Buie T, Fuchs GJ, Furuta GT, Kooros K, Levy J et al. (2010) Recommendations for evaluation and treatment of common gastrointestinal problems in children with ASDs. Pediatrics 125: S19-S29. doi:10.1542/peds.2009-1878D. PubMed: .
    1. Adams JB, Johansen LJ, Powell LD, Quig D, Rubin RA (2011) Gastrointestinal flora and gastrointestinal status in children with autism-comparisons to typical children and correlation with autism severity. BMC Gastroenterol 11: 22. doi:10.1186/1471-230X-11-22. PubMed: .
    1. Fombonne E (2009) Epidemiology of pervasive developmental disorders. Pediatr Res 65: 591-598. doi:10.1203/PDR.0b013e31819e7203. PubMed: .
    1. Baron-Cohen S, Scott FJ, Allison C, Williams J, Bolton P et al. (2009) Prevalence of autism-spectrum conditions: UK school-based population study. Br J Psychiatry 194: 500-509. doi:10.1192/bjp.bp.108.059345. PubMed: .
    1. Benach JL, Li E, Mcgovern MM (2012) A microbial association with autism. mBio 3: 1-3. doi:10.3391/mbi.2012.3.1.01. PubMed: .
    1. Dietert RR, Dietert JM, DeWitt JC (2011) Environmental risk factors for autism. Emerg Health Threats J 4: 7111.
    1. Mulloy A, Lang R, O'Reilly M, Sigafoos J, Lancioni G et al. (2010) Gluten-free and casein-free diets in the treatment of autism spectrum disorders: a systematic review. Res Autism Spect. Drosophila Inf Serv 4: 328-339.
    1. Sandler RH, Finegold SM, Bolte ER, Buchanan CP, Maxwell AP et al. (2000) Short-term benefit from oral vancomycin treatment of regressive-onset autism. J Child Neurol 15: 429-435. doi:10.1177/088307380001500701. PubMed: .
    1. Heberling CA , Dhurjati PS, Sasser M (2013) Hypothesis for a systems connectivity model of autism spectrum disorder pathogenesis: links to gut bacteria, oxidative stress, and intestinal permeability. Med Hypotheses 80: 264-270. doi:10.1016/j.mehy.2012.11.044. PubMed: .
    1. Finegold SM (2011) State of the art; microbiology in health and disease. Intestinal bacterial flora in autism. Anaerobe 17: 367-368. doi:10.1016/j.anaerobe.2011.03.007. PubMed: .
    1. Finegold SM, Downes J, Summanen PH (2012) Microbiology of regressive autism. Anaerobe 18: 260-262. doi:10.1016/j.anaerobe.2011.12.018. PubMed: .
    1. Kirsten TB, Chaves-Kirsten GP, Chaible LM, Silva AC, Martins DO et al. (2012) Hypoactivity of the central dopaminergic system and autistic-like behavior induced by a single early prenatal exposure to lipopolysaccharide. J Neurosci Res 90: 1903-1912. doi:10.1002/jnr.23089. PubMed: .
    1. Louis P (2012) Does the human gut microbiota contribute to the etiology of autism spectrum disorders? Dig Dis Sci 57: 1987-1989. doi:10.1007/s10620-012-2286-1. PubMed: .
    1. Petrof EO, Claud EC, Gloor GB, Allen-Vercoe E (2013) Microbial ecosystems therapeutics: a new paradigm in medicine? Benef Microbes 4: 53-65. doi:10.3920/BM2012.0039. PubMed: .
    1. Kuczynski J, Lauber CL, Walters WA, Parfrey LW, Clemente JC et al. (2012) Experimental and analytical tools for studying the human microbiome. Nat Rev Genet 13: 47-58. PubMed: .
    1. Qin J, Li R, Raes J, Arumugam M, Burgdorf KS et al. (2010) A human gut microbial gene catalogue established by metagenomic sequencing. Nature 464: 59-65. doi:10.1038/nature08821. PubMed: .
    1. Blaser MJ (2010) Harnessing the power of the human microbiome. Proc Natl Acad Sci U_S_A 107: 6125-6126. doi:10.1073/pnas.1002112107. PubMed: .
    1. Sekirov I, Russell SL, Antunes LCM, Finlay BB (2010) Gut microbiota in health and disease. Physiol Rev 90: 859-904. doi:10.1152/physrev.00045.2009. PubMed: .
    1. Williams BL, Hornig M, Buie T, Bauman ML, Paik MC (2012) Impaired carbohydrate digestion and transport and mucosal dysbiosis in the intestines of children with autism and gastrointestinal disturbances. PLOS ONE 6: e24585 PubMed: .
    1. Khachatryan ZA, Ktsoyan ZA, Manukyan GP, Kelly D, Ghazaryan KA et al. (2008) Predominant role of host genetics in controlling the composition of gut microbiota. PLOS ONE 3: e3064. doi:10.1371/journal.pone.0003064. PubMed: .
    1. Mariat D, Firmesse O, Levenez F, Guimarăes VD, Sokol H et al. (2009) The Firmicutes/Bacteroidetes ratio of the human microbiota changes with age. BMC Microbiol 9: 123. doi:10.1186/1471-2180-9-123. PubMed: .
    1. Larsen N, Vogensen FK, van den Berg FWJ, Nielsen DS, Andreasen AS et al. (2010) Gut microbiota in human adults with type 2 diabetes differs from non-diabetic adults. PLOS ONE 5: e9085. doi:10.1371/journal.pone.0009085. PubMed: .
    1. Zimmer J, Lange B, Frick J-S, Sauer H, Zimmermann K et al. (2012) A vegan or vegetarian diet substantially alters the human colonic faecal microbiota. Eur J Clin Nutr 66: 53-60. doi:10.1038/ejcn.2011.141. PubMed: .
    1. Prakash S, Rodes L, Coussa-Charley M, Tomaro-Duchesneau C (2011) Gut microbiota: next frontier in understanding human health and development of biotherapeutics. Biol Targ Ther 5: 71-86. PubMed: .
    1. Fujimura KE, Slusher NA, Cabana MD, Lynch SV (2010) Role of the gut microbiota in defining human health. Expert Rev Anti Infect Ther 8: 435-454. doi:10.1586/eri.10.14. PubMed: .
    1. Francavilla R, Calasso M, Calace L, Siragusa S, Ndagijimana M et al. (2012) Effect of lactose on gut microbiota and metabolome of infants with cow’s milk allergy. Pediatr Allergy Immunol 23: 420-427. doi:10.1111/j.1399-3038.2012.01286.x. PubMed: .
    1. Brugman S, Klatter FA, Visser JTJ, Wildeboer-Veloo ACM, Harmsen HJM et al. (2006) Antibiotic treatment partially protects against Type 1 diabetes in the Bio-Breeding diabetes-prone rat. Is the gut flora involved in the development of Type 1 diabetes? Diabetologia 49: 2105-2108. doi:10.1007/s00125-006-0334-0. PubMed: .
    1. Di Cagno R, Rizzello CG, Gagliardi F, Ricciuti P, Ndagijimana M et al. (2009) Different fecal microbiotas and volatile organic compounds in treated and untreated children with celiac disease. Appl Environ Microbiol 75: 3963-3971. doi:10.1128/AEM.02793-08. PubMed: .
    1. Di Cagno R, De Angelis M, De Pasquale I, Ndagijimana M, Vernocchi P et al. (2011) Duodenal and faecal microbiota of celiac children: molecular, phenotype and metabolome characterization. BMC Microbiol 11: 219. doi:10.1186/1471-2180-11-219. PubMed: .
    1. Forsythe P, Kunze WA (2012) Voices from within: gut microbes and the CNS. Cell Mol Life Sci, 70: 55–69. doi:10.1007/s00018-012-1028-z. PubMed: .
    1. Bravo JA, Forsythe P, Chew MV, Escaravage E, Savignac HM et al. (2011) Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. Proc Natl Acad Sci U_S_A 108: 16050-16055. doi:10.1073/pnas.1102999108. PubMed: .
    1. Finegold SM (2008) Therapy and epidemiology of autism-clostridial spores as key elements. Med Hypotheses 70: 508-511. doi:10.1016/j.mehy.2007.07.019. PubMed: .
    1. Parracho HM, Bingham MO, Gibson GR, McCartney AL (2005) Differences between the gut microflora of children with autistic spectrum disorders and that of healthy children. J Med Microbiol 54: 987-991. doi:10.1099/jmm.0.46101-0. PubMed: .
    1. Finegold SM, Dowd SE, Gontcharova V, Liu C, Henley KE et al. (2010) Pyrosequencing study of fecal microbiota of autistic and control children. Anaerobe 16: 444-453. doi:10.1016/j.anaerobe.2010.06.008. PubMed: .
    1. Finegold SM (2011) Desulfovibrio species are potentially important in regressive autism. Med Hypotheses 77: 270-274. doi:10.1016/j.mehy.2011.04.032. PubMed: .
    1. Williams BL, Hornig M, Parekh T, Lipkin WI (2012) Application of novel PCR-based methods for detection, quantitation, and phylogenetic characterization of Sutterella species in intestinal biopsy samples from children with autism and gastrointestinal disturbances. mBio 3: e00261-11 PubMed: .
    1. Wang L, Christophersen CT, Sorich MJ, Gerber JP, Angley MT et al. (2011) Low relative abundances of the mucolytic bacterium Akkermansia muciniphila and Bifidobacterium spp. in feces of children with autism. Appl Environ Microbiol 77: 6718-6721. doi:10.1128/AEM.05212-11. PubMed: .
    1. Bolte ER (1998) Autism and Clostridium tetani . Med Hypotheses 51: 133-144. doi:10.1016/S0306-9877(98)90107-4. PubMed: .
    1. Gondalia SV, Palombo EA, Knowles SR, Austin DW (2010) Faecal microbiota of individuals with autism spectrum disorder. Eur J Appl Physiol 6: 24-29.
    1. Persico AM, Napolioni V (2012) Urinary p-cresol in autism spectrum disorder. Neurotoxicol Teratol 36: 82-90. PubMed: .
    1. Shimmura C, Suda S, Tsuchiya KJ, Hashimoto K, Ohno K et al. (2011) Alteration of plasma glutamate and glutamine levels in children with high-functioning autism. PLOS ONE 6: e25340. doi:10.1371/journal.pone.0025340. PubMed: .
    1. Lord C, Rutter M, Le Couteur A (1994) Autism diagnostic interview-revised: a revised version of a diagnostic interview for caregivers of individuals with possible pervasive developmental disorders. J Autism Dev Disord 24: 659-685. doi:10.1007/BF02172145. PubMed: .
    1. Lord C, Risi S, Lambrecht L, Cook EH Jr., Leventhal BL et al. (2000) The ADOS-G (Autism Diagnostic Observation Schedule-Generic): a standard measure of social communication deficit associated with autism disorders. J Autism Dev Disord 30: 205-223. doi:10.1023/A:1005592401947. PubMed: .
    1. Kramer JJ, Conoley JC, Murphy LL, editors (1992) Review of the childhood autism rating scale. The Eleventh Mental Measurements Yearbook. Lincoln: University of Nebraska; pp. 170-171.
    1. De Giacomo A, Portoghese C, Martinelli D, Fanizza I, L’Abate L et al. (2009) Imitation and communication skills development in children with pervasive developmental disorders. Neuropsychiatr Dis Treat 5: 355-362. PubMed: .
    1. Gowen CM, Fong SS (2010) Genome-scale metabolic model integrated with RNAseq data to identify metabolic states of Clostridium thermocellum . Biotechnol J 7: 759-767. PubMed: .
    1. Suchodolski JS, Dowd SE, Wilke V, Steiner JM, Jergens AE (2012) 16S rRNA gene pyrosequencing reveals bacterial dysbiosis in the duodenum of dogs with idiopathic inflammatory bowel disease. PLOS ONE 7(6): e39333. doi:10.1371/journal.pone.0039333. PubMed: .
    1. Gontcharova V, Youn E, Wolcott RD, Hollister EB, Gentry TJ et al. (2010) Black box chimera check (B2C2): a windows-based software for batch depletion of chimeras from bacterial 16 S rRNA gene datasets. Open Microbiol J 4: 47-52. doi:10.2174/1874285801004010047. PubMed: .
    1. Dowd SE, Zaragoza J, Rodriguez JR, Oliver MJ, Payton PR (2005) network distributed basic local alignment search toolkit (W.ND-BLAST). BMC Bioinformatics 6: 93.
    1. Edgar RC (2010) Search and clustering orders of magnitude faster than BLAST. Bioinformatics 26: 2460-2461. doi:10.1093/bioinformatics/btq461. PubMed: .
    1. Cole JR, Wang Q, Cardenas E, Fish J, Chai B et al. (2009) The ribosomal database project: improved alignments and new tools for rRNA analysis. Nucleic Acids Res 37: D141-D145. doi:10.1093/nar/gkp353. PubMed: .
    1. Dowd SE, Wolcott RD, Sun Y, McKeehan T, Smith E et al. (2008) Polymicrobial nature of chronic diabetic foot ulcer biofilm infections determined using bacterial tag encoded FLX amplicon pyrosequencing (bTEFAP). PLOS ONE 3: e3326. doi:10.1371/journal.pone.0003326. PubMed: .
    1. Chao A, Bunge J (2002) Estimating the number of species in a stochastic abundance model. Biometrics 58: 531-539. doi:10.1111/j.0006-341X.2002.00531.x. PubMed: .
    1. Shannon CE, Weaver W (1949) The mathematical theory of information. AT&T Tech J 27: 359-423.
    1. Macfarlane S, Quingley ME, Hopkins MJ, Newton DF, Macfarlane GT (1998) Polysaccharide degradation by human intestinal bacteria during growth under multi-substrate limiting conditions in a three-stage continuous culture system. FEMS Microbiol Ecol 26: 231-243. doi:10.1111/j.1574-6941.1998.tb00508.x.
    1. Serrazanetti DI, Ndagijimana M, Sado-Kamdem SL, Corsetti A, Vogel RF et al. (2011) Acid stress-mediated metabolic shift in Lactobacillus sanfranciscensis LSCE1. Appl Environ Microbiol 77: 2656-2666. doi:10.1128/AEM.01826-10. PubMed: .
    1. Ndagijimana M, Laghi L, Vitali B, Placucci G, Brigidi P et al. (2009) Effect of a synbiotic food consumption on human gut metabolic profiles evaluated by 1 H Nuclear Magnetic Resonance spectroscopy. Int J Food Microbiol 134: 147-153. doi:10.1016/j.ijfoodmicro.2009.04.016. PubMed: .
    1. Gondalia SV, Palombo EA, Knowles SR, Cox SB, Meyer D et al. (2012) Molecular characterisation of gastrointestinal microbiota of children with autism (with and without gastrointestinal dysfunction) and their neurotypical siblings. Autism Res 5: 419-427. doi:10.1002/aur.1253. PubMed: .
    1. Serino M, Luche E, Gres S, Baylac A, Bergé M et al. (2012) Metabolic adaptation to a high-fat diet is associated with a change in the gut microbiota. Gut 61: 543-553. doi:10.1136/gutjnl-2011-301012. PubMed: .
    1. MacFabe DF, Cain NE, Boon F, Ossenkopp KP, Cain DP (2011) Effects of the enteric bacterial metabolic product propionic acid on object-directed behavior, social behavior, cognition, and neuroinflammation in adolescent rats: relevance to autism spectrum disorder. Behav Brain Res 217: 47-54. doi:10.1016/j.bbr.2010.10.005. PubMed: .
    1. Peris-Bondia F, Latorre A, Artacho A, Moya A, D’Auria G (2011) The active human gut microbiota differs from the total microbiota. PLOS ONE 6(7): e22448. doi:10.1371/journal.pone.0022448. PubMed: .
    1. Razack R, Seidner DL (2007) Nutrition in inflammatory bowel disease. Curr Opin Gastroenterol 23: 400-405. doi:10.1097/MOG.0b013e3281ddb2a3. PubMed: .
    1. Devillard E, McIntosh FM, Duncan SH, Wallace RJ (2007) Metabolism of linoleic acid by human gut bacteria: different routes for biosynthesis of conjugated linoleic acid. J Bacteriol 189: 2566-2570. doi:10.1128/JB.01359-06. PubMed: .
    1. Medina M, De Palma G, Ribes-Koninckx C, Calabuig M, Sanz Y (2008) Bifidobacterium strains suppress in vitro the pro-inflammatory milieu triggered by the large intestinal microbiota of coeliac patients. J Inflamm 5: 19. doi:10.1186/1476-9255-5-19. PubMed: .
    1. Salazar N, Gueimonde M, Hernandez-Barranco AM, Ruas-Madiedo P, de los Reyes-Gavilan CG (2008) Exopolysaccharides produced by intestinal Bifidobacterium strains act as fermentable substrates for human intestinal bacteria. Appl Environ Microbiol 74: 4737-4745. doi:10.1128/AEM.00325-08. PubMed: .
    1. Nicholson JK, Holmes E, Kinross J, Burcelin R, Gibson G et al. (2012) Host-gut microbiota metabolic interactions. Science 336: 1262-1267. doi:10.1126/science.1223813. PubMed: .
    1. Flint HJ, Wallace RJ (2010) Obesity and colorectal cancer risk: impact of the gut microbiota and weight-loss diets. Open Obes J 2: 50-62.
    1. Wendy RR, Duncan SH, Scobbie L, Duncan G, Cantlay L et al. (2013) Major phenylpropanoid-derived metabolites in the human gut can arise from microbial fermentation of protein. Mol Nutr Food Res 57: 523-535. doi:10.1002/mnfr.201200594. PubMed: .
    1. Sheldon AL, Robinson MB (2007) The role of glutamate transporters in neurodegenerative diseases and potential opportunities for intervention. Neurochem Int 51: 333-355. doi:10.1016/j.neuint.2007.03.012. PubMed: .
    1. van Duynhoven J, Vaughan EE, Jacobs DM, Kemperman RA, van Velzen EJJ et al. (2011) Metabolic fate of polyphenols in the human superorganism. Proc Natl Acad Sci U_S_A 108: 4531-4538. doi:10.1073/pnas.1000098107. PubMed: .
    1. Strassburg CP, Strassburg A, Kneip S, Barut A, Tukey RH et al. (2002) Developmental aspects of human hepatic drug glucuronidation in young children and adults. Gut 50: 259-265. doi:10.1136/gut.50.2.259. PubMed: .
    1. Diczfalusy MA, Björkhem I, Einarsson C, Hillebrant CG, Alexson SE (2001) Characterization of enzymes involved in formation of ethyl esters of long-chain fatty acids in humans. J Lipid Res 42: 1025-1032. PubMed: .
    1. Satokari RM, Vaughan EE, Akkermans AD, Saarela M, de Vos WM (2001) Bifidobacterial diversity in human feces detected by genus-specific polymerase chain reaction and denaturing gradient gel electrophoresis. Appl Environ Microbiol 67: 504-513. doi:10.1128/AEM.67.2.504-513.2001. PubMed: .
    1. Wall R, Ross PR, Shanahan F, Quigley EM, Dinan TG et al. (2012) Influence of gut microbiota and manipulation by probiotics and prebiotics on host tissue fat: potential clinical implications. Lipids Technol 24: 10.
    1. Bansal T, Alaniz RC, Wood TK, Jayaraman A (2010) The bacterial signal indole increases epithelial-cell tight-junction resistance and attenuates indicators of inflammation. Proc Natl Acad Sci U_S_A 107: 228-233. doi:10.1073/pnas.0906112107. PubMed: .
    1. Finegold SM, Molitoris D, Song Y, Liu C, Vaisanen ML et al. (2002) Gastrointestinal microflora studies in late-onset autism. Clin Infect Dis 35: S6-16. doi:10.1086/341914. PubMed: .

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