title: Pseudotrisomy 13 syndrome: use of homozygosity mapping to target candidate genes.
abstract: Pseudotrisomy 13 syndrome is characterised by holoprosencephaly with or without polydactyly, but with a normal karyotype. The genetic cause of this syndrome remains unclear, but it is thought to be autosomal recessive. In order to identify possible candidate genes, we identified regions of homozygosity in the DNA of an affected foetus, which was the seventh pregnancy of a healthy non-consanguineous Cook Island Maori couple; this ethnic group derives from a small founder population. Several large regions of homozygosity were identified using a high density array. We excluded two candidate genes that lay within these regions, and suggest that Pseudotrisomy 13 syndrome might not be monogenic and that a larger cohort of patients should be analysed using high density dosage/SNP arrays as well as whole exome sequencing in order to clarify the genetic underpinning of this rare syndrome.
authors.affiliation: Diagnostic Genetics, LabPlus, Auckland City Hospital, New Zealand.
authors.forename: Renate
authors.initials: R
authors.lastname: Marquis-Nicholson
authors.forename: Salim
authors.initials: S
authors.lastname: Aftimos
authors.forename: Fern
authors.initials: F
authors.lastname: Ashton
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Love
authors.forename: Peter
authors.initials: P
authors.lastname: Stone
authors.forename: Jeannette
authors.initials: J
authors.lastname: McFarlane
authors.forename: Alice M
authors.initials: AM
authors.lastname: George
authors.forename: Donald R
authors.initials: DR
authors.lastname: Love
mesh_terms: D002874:Chromosome Mapping; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D005260:Female; D005320:Fetal Macrosomia / Q000175:diagnosis / Q000235:genetics*; D005808:Genes, Recessive; D006228:Hand Deformities, Congenital / Q000175:diagnosis / Q000235:genetics*; D016142:Holoprosencephaly / Q000175:diagnosis / Q000235:genetics*; D006720:Homozygote; D006801:Humans; D007621:Karyotyping; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D017689:Polydactyly / Q000175:diagnosis / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D011247:Pregnancy; D014314:Trisomy / Q000175:diagnosis / Q000235:genetics*