title: Chromosome 15q11-q13 copy number gain detected by array-CGH in two cases with a maternal methylation pattern.
abstract: BACKGROUND
  The 15q11-q13 region contains many low copy repeats and is well known for its genomic instability. Several syndromes are associated with genomic imbalance or copy-number-neutral uniparental disomy. We report on two patients: Patient 1 is a boy with developmental delay and autism; and Patient 2 is a girl with developmental delay, hypotonia and dysmorphism. We performed analyses to delineate their dosage in the 15q region, determine whether the patients' dosage correlates with phenotypic severity, and whether genes in the amplified regions are significantly associated with identified functional networks.
  
  
  RESULTS
  For the proximal region of 15q, molecular cytogenetic analysis with Agilent oligonucleotide array showed a copy number of 3 for Patient 1 and a copy number of 4 for Patient 2. Fluorescent in situ hybridization analysis of Patient 2 showed two different populations of cells with different marker chromosomes. Methylation analysis of the amplified region showed that the extra copies of small nuclear ribonucleoprotein polypeptide N gene were of maternal origin. Phenotypic severity did not correlate with the size and dosage of 15q, or whether the amplification is interstitial or in the form of a supernumerary marker. Pathway analysis showed that in Patient 2, the main functional networks that are affected by the genes from the duplicated/triplicated regions are developmental disorder, neurological disease and hereditary disease.
  
  
  CONCLUSIONS
  The 15q11-q13 gains that were found in both patients could explain their phenotypic presentations. This report expands the cohort of patients for which 15q11-q13 duplications are molecularly characterized.
authors: Genetics Service, KK Women's & Children's Hospital, 100 Bukit Timah Road 229899 Singapore, Singapore.
authors: Ee-Shien
authors: ES
authors: Tan
authors: Cytogenetics Laboratory, KK Women's & Children's Hospital, 100 Bukit Timah Road 229899 Singapore, Singapore.
authors: Min-Hwee
authors: MH
authors: Yong
authors: KK Research Laboratory, KK Women's & Children's Hospital, 100 Bukit Timah Road 229899 Singapore, Singapore.
authors: Eileen Cp
authors: EC
authors: Lim
authors: Genomax Technologies Pte Ltd, 51 Science Park Road, #04-15 117586 Singapore, Singapore.
authors: Zhi-Hui
authors: ZH
authors: Li
authors: KK Research Laboratory, KK Women's & Children's Hospital, 100 Bukit Timah Road 229899 Singapore, Singapore.
authors: Maggie Sy
authors: MS
authors: Brett
authors: KK Research Laboratory, KK Women's & Children's Hospital, 100 Bukit Timah Road 229899 Singapore, Singapore ; Office of Clinical Sciences, Duke-NUS Graduate Medical School, 8 College Road 169857 Singapore, Singapore.
authors: Ene-Choo
authors: EC
authors: Tan
keywords: 15q duplication syndrome; Array comparative genomic hybridization (aCGH); Autism; Copy number gain; Developmental delay; Fluorescence in situ hybridization (FISH); Marker chromosome