TY - JOUR T1 - Further delineation of Pitt–Hopkins syndrome: phenotypic and genotypic description of 16 novel patients JF - Journal of Medical Genetics JO - J Med Genet SP - 738 LP - 744 DO - 10.1136/jmg.2008.060129 VL - 45 IS - 11 AU - C Zweier AU - H Sticht AU - E K Bijlsma AU - J Clayton-Smith AU - S E Boonen AU - A Fryer AU - M T Greally AU - L Hoffmann AU - N S den Hollander AU - M Jongmans AU - S G Kant AU - M D King AU - S A Lynch AU - S McKee AU - A T Midro AU - S-M Park AU - V Ricotti AU - E Tarantino AU - M Wessels AU - M Peippo AU - A Rauch Y1 - 2008/11/01 UR - http://jmg.bmj.com/content/45/11/738.abstract N2 - Background: Haploinsufficiency of the gene encoding for transcription factor 4 (TCF4) was recently identified as the underlying cause of Pitt–Hopkins syndrome (PTHS), an underdiagnosed mental-retardation syndrome characterised by a distinct facial gestalt, breathing anomalies and severe mental retardation.Methods: TCF4 mutational analysis was performed in 117 patients with PTHS-like features.Results: In total, 16 novel mutations were identified. All of these proven patients were severely mentally retarded and showed a distinct facial gestalt. In addition, 56% had breathing anomalies, 56% had microcephaly, 38% had seizures and 44% had MRI anomalies.Conclusion: This study provides further evidence of the mutational and clinical spectrum of PTHS and confirms its important role in the differential diagnosis of severe mental retardation. ER -