Antiepileptic/teratogen valproate (VPA) is a histone deacetylase inhibitor/ epigenetic drug proposed for the antitumor therapy where it is generally crucial to target poorly or undifferentiated cells to prevent a recurrence. Transplanted rodent gastrulating embryos-proper (primitive streak and three germ layers) are the source of teratoma/teratocarcinoma tumors. Human primitive-streak remnants develop sacrococcygeal teratomas that may recur even when benign (well differentiated). To screen for unknown VPA impact on teratoma-type tumors, we used original 2-week embryoderived teratoma in vitro biological system completed by a spent media metabolome analysis. Gastrulating 9.5-day-old rat embryos-proper were cultivated in Eagle's minimal essential medium (MEM) with 50% rat serum (controls) or with the addition of 2 mM VPA. Spent media metabolomes were analyzed by FTIR. Compared to controls, VPA acetylated histones; significantly diminished overall teratoma growth, impaired survival, increased the apoptotic index, and decreased proliferation index and incidence of differentiated tissues (e.g., neural tissue). Control teratomas continued to grow and differentiate for 14 days in isotransplants in vivo, but in vitro VPA-treated teratomas resorbed. Principal component analysis of FTIR results showed that spent media metabolomes formed well-separated clusters reflecting the treatment and day of cultivation. In metabolomes of VPA-treated teratomas, we found elevation of previously described histone acetylation biomarkers [amide I a-helix and A(CH 3)/A(CH 2)]) with apoptotic biomarkers within the amide I region for b-sheets, and unordered and CH 2 vibrations of lipids. VPA may be proposed for therapy of the undifferentiated component of teratoma tumors and this biological system Abbreviations ASD, autism spectrum disorder; EC, embryonal carcinoma; GTS, growing teratoma syndrome; HDACi, histone deacetylase inhibitor; MEM, minimal essential medium; PCA, principal component analysis; PCNA, proliferating cell nuclear antigen; RMSEC, root mean square error of calibration; RMSECV, root mean square error of cross-validation; SAHA, suberoylanilidehydroxamic acid; VPA, valproate; WEC, whole rat embryo.

mutation (40%) in the TCF4 gene located at 18q21.2 and encoding Transcription Factor 4. Variants in TCF4 usually occur de novo in children with severe phenotype, milder phenotypes inherited autosomal dominant We have examined 9 patients (4 boys and 5 girls) with Pitt-Hopkins aged 1 to 12 years.Array-comparative genomic hybridization was performed in 5 children Target areas of the exome were investigated by massive parallel sequencing (NGS) in 4 cases. Validation of the identified variants was carried out by the Sanger method.De novo microdeletions 1 revealed in 5 cases: arr 18q21.2q21.32 (51266708_56293087) ×1, arr 18q21.2 (52691678_52999165) ×1, arr 18q21.2q21.1 (50029734_61654329) ×1, arr 18q21.2q21.31 (51620900_54883094) ×1, arr18q21.2q21.31 (49493248_55403360) ×1. Detected deletions was from 307 Kb to 1162 Mb. We identified 4 different mutations in the TCF4 gene in 4 patients with Pitt-Hopkins syndrome: c.961+2T>C, c.1452 +1G>T, c.1634C>G, c.2033G>A. Spectrum of mutations represented by splicing site mutations, nonsense and missense mutations. All children had severe motor development delay and muscle hypotonia. Only one child was able to walk independently. All children had severe mental retardation. Expressive speech represented by vocalizations, individual words. Autistic and behavioral disorders were in 6 children. Severe episodes of hyperventilation followed by apnea observed in one child. Dysmorphic features included coarse face, protruding lower face, deep-set eyes, upslanting palpebral fissures, high, wide nose bridge, wide open mouth, cupid's bow upper lipthick, fleshy lips, cup-shaped ears. Three children diagnosed with myopia, scoliosis in one case. Brain MRI (in 4 children) show hypoplasia/dysplasia of the corpus callosum, atrophy/hypoplasia of the cerebellum, Dandy -Walker anomaly, hydrocephalus, small hippocampus size. Conclusion Pitt-Hopkins syndrome is important for the differential diagnosis in children with severe mental retardation and behavioral disorders.2,4