title: Lissencephaly with der(17)t(17;20)(p13.3;p12.2)mat.
abstract: The isolated lissencephaly sequence may be caused by point mutations of the LIS1 gene or by FISH-detectable microdeletions of the 17p13.3 region, which carries the LIS1 gene. These have various patterns of phenotypic presentations, including the Miller-Dieker syndrome (MDS). Approximately 20% of these deletions are associated with a derivative chromosome 17 inherited from a parent who has a balanced reciprocal translocation involving chromosome 17 and another chromosome. We report a case of lissencephaly associated with a maternally inherited unbalanced translocation involving chromosome arms 17p and 20p. This results in partial monosomy of 17p13.3-->pter and partial trisomy of 20p12.2-->pter. To our knowledge, this is the first report of a reciprocal translocation between 17p and 20p. Our patient has a combination of findings of the MDS and trisomy 20p, along with several unique anomalies not described in either of those two conditions. This report may contribute to the delineation of a phenotype resulting from partial monosomy 17p and partial trisomy of 20p.
authors.affiliation: F. Clarke Fraser Clinical Genetics Unit, Division of Medical Genetics, Department of Pediatrics, Montreal Children's Hospital, Montreal, Quebec, Canada.
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Thomas
authors.forename: Alessandra M V
authors.initials: AM
authors.lastname: Duncan
authors.forename: Claudette
authors.initials: C
authors.lastname: Bardin
authors.forename: Vazken M Der
authors.initials: VM
authors.lastname: Kaloustian
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics* / Q000473:pathology; D002871:Chromosome Banding; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics*; D002890:Chromosomes, Human, Pair 20 / Q000235:genetics*; D005192:Family Health; D006801:Humans; D007231:Infant, Newborn; D008607:Intellectual Disability / Q000473:pathology*; D007621:Karyotyping; D008297:Male; D012640:Seizures / Q000473:pathology*; D013577:Syndrome; D014178:Translocation, Genetic