PT - JOURNAL ARTICLE AU - Moira Blyth AU - Viv Maloney AU - Sarah Beal AU - Morag Collinson AU - Shuwen Huang AU - John Crolla AU - I Karen Temple AU - Diana Baralle TI - Pallister-Killian syndrome: a study of 22 British patients AID - 10.1136/jmedgenet-2014-102877 DP - 2015 Jul 01 TA - Journal of Medical Genetics PG - 454--464 VI - 52 IP - 7 4099 - http://jmg.bmj.com/content/52/7/454.short 4100 - http://jmg.bmj.com/content/52/7/454.full SO - J Med Genet2015 Jul 01; 52 AB - Background Pallister-Killian syndrome is a rare, sporadic condition caused by mosaic tetrasomy of the short arm of chromosome 12 (12p). The main features are intellectual disability, seizures, dysmorphic features and a variety of congenital malformations. Most available information comes from individual case reports. We report the results of a British study into Pallister-Killian syndrome, which is the first to provide comprehensive data on a population-based sample.Method A detailed phenotypical study was carried out in Great Britain. All individuals with Pallister-Killian syndrome were eligible to participate. Each participant underwent a structured history, developmental assessment and clinical examination. Buccal mucosal samples were analysed by interphase fluorescence in situ hybridization (FISH) and blood samples by array comparative genomic hybridization (CGH). Genotype-phenotype correlations were sought in these tissues and existing skin biopsy reports.Results Twenty-two patients with Pallister-Killian syndrome, ranging from 4 months to 31 years were recruited and comprehensive data on each obtained. The birth incidence was 5.1 per million live births. Array CGH only suggested the diagnosis in 15.8% but buccal FISH could have made the diagnosis in 75.0%. There was no genotype-phenotype correlation in any of the tissues studied. This study shows that the high birth weights and profound intellectual disability classically described in Pallister-Killian syndrome are not universal. Mild or moderate intellectual disability was present in 27.6% of this cohort and all birth weights were within 2.67SD of the mean. New features which have not previously been recognised as part of Pallister-Killian syndrome include anhydrosis/ hypohydrosis and episodic hyperventilation, suggesting involvement of the autonomic system.