title: 8p23.1 duplication syndrome; a novel genomic condition with unexpected complexity revealed by array CGH.
abstract: The 8p23.1 deletion syndrome is established but not an equivalent duplication syndrome. Here, we report five patients; a de novo prenatal case and two families in which 8p23.1 duplications have been directly transmitted from mothers to children. Dual-colour fluorescent in situ hybridisation, multiplex ligation-dependent probe amplification analysis and customised oligonucleotide array comparative genomic hybridisation (oaCGH) indicated an approximately 3.75 Mb duplication of most of band 8p23.1 between the olfactory receptor/defensin repeats (ORDRs) in all cases. However, oaCGH revealed an additional duplication of 500 kb adjacent to the proximal ORDR in Family 1 and an additional deletion of 3.14 Mb within the Nablus Mask-Like Facial Syndrome region of 8q22.1 in Family 2. Copy number variation at introns 4-5 of the GATA4 gene was also identified. This 8p23.1 duplication syndrome is associated with a characteristic facial phenotype including a prominent forehead and arched eyebrows. Adrenal insufficiency, Tetralogy of Fallot, partial 2/3 syndactyly of the toes and cleft palate in some individuals may be explained by ascertainment bias, incomplete penetrance and/or the presence of the microdeletion in Family 2. The duplication is compatible with normal early childhood development but, although our adult cases live independent lives with varying degrees of support, learning difficulties have been experienced by some family members. We conclude that the 8p23.1 duplication syndrome is a genomic condition with an emerging but variable phenotype that may be under-diagnosed. Our results demonstrate that direct transmission does not distinguish genuine duplications from euchromatic variants and illustrate the power of array CGH to reveal unexpected additional imbalances in affected patients.
authors.affiliation: National Genetics Reference Laboratory (Wessex), Salisbury NHS Foundation Trust, Salisbury, Wiltshire, UK. john.barber@salisbury.nhs.uk
authors.forename: John C K
authors.initials: JC
authors.lastname: Barber
authors.forename: Viv K
authors.initials: VK
authors.lastname: Maloney
authors.forename: Shuwen
authors.initials: S
authors.lastname: Huang
authors.forename: David J
authors.initials: DJ
authors.lastname: Bunyan
authors.forename: Lara
authors.initials: L
authors.lastname: Cresswell
authors.forename: Esther
authors.initials: E
authors.lastname: Kinning
authors.forename: Anna
authors.initials: A
authors.lastname: Benson
authors.forename: Tim
authors.initials: T
authors.lastname: Cheetham
authors.forename: Jonathan
authors.initials: J
authors.lastname: Wyllie
authors.forename: Sally Ann
authors.initials: SA
authors.lastname: Lynch
authors.forename: Simon
authors.initials: S
authors.lastname: Zwolinski
authors.forename: Laura
authors.initials: L
authors.lastname: Prescott
authors.forename: Yanick
authors.initials: Y
authors.lastname: Crow
authors.forename: Rob
authors.initials: R
authors.lastname: Morgan
authors.forename: Emma
authors.initials: E
authors.lastname: Hobson
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics*; D000328:Adult; D002869:Chromosome Aberrations; D002898:Chromosomes, Human, Pair 8 / Q000235:genetics*; D003582:Cytogenetics; D005260:Female; D018628:Gene Dosage; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008967:Molecular Biology; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D011247:Pregnancy