title: Angelman Syndrome Caused by Chromosomal Rearrangements: A Case Report of 46,XX,+der(13)t(13;15)(q14.1;q12)mat,-15 with an Atypical Phenotype and Review of the Literature.
abstract: Less than 1% of the cases with Angelman syndrome (AS) are caused by chromosomal rearrangements. This category of AS is not well defined and may manifest atypical phenotypes. Here, we report a girl with AS due to der(13)t(13;15)(q14.1;q12)mat. SNP array detected the precise deletion/duplication points and the parental origin of the 15q deletion. Multicolor FISH confirmed a balanced translocation t(13;15)(q14.1;q12) in her mother. Her facial appearance showed some features of dup(13)(pter→q14). Also, she lacked the most characteristic and unique behavioral symptoms of AS, i.e., frequent laughter, happy demeanor, and easy excitability. A review of the literature indicated that AS cases caused by chromosomal rearrangements can be classified into 2 major categories and 4 groups. The first category is paternal uniparental disomy 15, which is subdivided into isodisomy by de novo rob(15;15) and heterodisomy caused by paternal translocation. The second category is the deletion of the AS locus due to maternal reciprocal translocation, which is subdivided into 2 groups associated with partial monosomy by 3:1 segregation and partial trisomy by adjacent-2 segregation. Classification into these categories facilitates the understanding of the mechanisms of chromosomal rearrangements and helps in accurate diagnosis and genetic counseling of these rare forms of AS.
authors: Division of Clinical Genetics, Multidisciplinary Medical Center, Kanazawa Medical University Hospital, Uchinada, Japan.
authors: Yo
authors: Y
authors: Niida
authors: Hitoshi
authors: H
authors: Sato
authors: Mamoru
authors: M
authors: Ozaki
authors: Masatsune
authors: M
authors: Itoh
authors: Kanju
authors: K
authors: Ikeno
authors: Etsuko
authors: E
authors: Takase
mesh_terms: D017204:Angelman Syndrome / Q000145:classification* / Q000235:genetics*; D002869:Chromosome Aberrations; D002872:Chromosome Deletion; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D002884:Chromosomes, Human, Pair 15 / Q000235:genetics; D041321:Chromosomes, Human, X / Q000235:genetics; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D008297:Male; D000072741:Maternal Inheritance / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D000072740:Paternal Inheritance / Q000235:genetics; D010641:Phenotype; D014178:Translocation, Genetic / Q000235:genetics; D014314:Trisomy / Q000235:genetics; D024182:Uniparental Disomy / Q000235:genetics