Complex small supernumerary marker chromosome with a 15q/16p duplication: clinical implications.
BACKGROUND
Complex small supernumerary marker chromosomes (sSMCs) consist of chromosomal material derived from more than one chromosome and have been implicated in reproductive problems such as recurrent pregnancy loss. They may also be associated with congenital abnormalities in the offspring of carriers. Due to its genomic architecture, chromosome 15 is frequently associated with rearrangements and the formation of sSMCs. Recently, several different CNVs have been described at 16p11.2, suggesting that this region is prone to rearrangements.


RESULTS
We detected the concomitant occurrence of partial trisomy 15q and 16p, due to a complex sSMC, in a 6-year-old girl with clinical phenotypic. The karyotype was analyzed by G and C banding, NOR staining, FISH and SNP array and defined as 47,XX,+der(15)t(15;16)(q13;p13.2)mat. The array assay revealed an unexpected complex sSMC containing material from chromosomes 15 and 16, due to an inherited maternal translocation (passed along over several generations). The patient's phenotype included microsomia, intellectual disability, speech delay, hearing impairment, dysphagia and other minor alterations.


CONCLUSIONS
This is the first report on the concomitant occurrence of partial trisomy 15q and 16p. The wide range of phenotypes associated with complex sSMCs represents a challenge for genotype-phenotype correlation studies, accurate clinical assessment of patients and genetic counseling.
Department of Gynecology and Obstetrics, Genetics Division, Faculdade de Medicina do ABC - FMABC, São Paulo, Brazil.
Denise M
DM
Christofolini
Department of Pathology, Cytogenomics Laboratory, LIM 03, HC-FMUSP, University of São Paulo, Av. Dr. Enéas de Carvalho Aguiar 255, São Paulo 05403-000, Brazil.
Flavia B
FB
Piazzon
Department of Gynecology and Obstetrics, Genetics Division, Faculdade de Medicina do ABC - FMABC, São Paulo, Brazil.
Carolina
C
Evo
Department of Gynecology and Obstetrics, Genetics Division, Faculdade de Medicina do ABC - FMABC, São Paulo, Brazil.
Fernanda A
FA
Mafra
Department of Gynecology and Obstetrics, Genetics Division, Faculdade de Medicina do ABC - FMABC, São Paulo, Brazil.
Stella R
SR
Cosenza
Department of Pathology, Cytogenomics Laboratory, LIM 03, HC-FMUSP, University of São Paulo, Av. Dr. Enéas de Carvalho Aguiar 255, São Paulo 05403-000, Brazil.
Alexandre T
AT
Dias
Department of Gynecology and Obstetrics, Genetics Division, Faculdade de Medicina do ABC - FMABC, São Paulo, Brazil.
Caio P
CP
Barbosa
Department of Gynecology and Obstetrics, Genetics Division, Faculdade de Medicina do ABC - FMABC, São Paulo, Brazil.
Bianca
B
Bianco
Department of Pathology, Cytogenomics Laboratory, LIM 03, HC-FMUSP, University of São Paulo, Av. Dr. Enéas de Carvalho Aguiar 255, São Paulo 05403-000, Brazil.
Leslie D
LD
Kulikowski
15q duplication; 16p duplication; Complex sSMC; Familial inheritance