Affiliations: Caritas St Elizabeth Medical Center, Tufts University,
Boston, MA, USA | Cytogenetics Laboratory of the 2nd Department of
Pediatrics, Aristotle University, AHEPA Hospital, Thessaloniki, Greece | Department of Neonatology, Hippocratic Hospital,
Thessaloniki, Greece | Department of Biological Chemistry and Molecular
Pharmacology, School of Medicine, Harvard University, Boston, MA, USA
Note: [] Correspondence: Alexandra Drakaki, MD, Caritas St Elizabeth,
Medical Center, Tufts University, 736 Cambridge St, Boston, MA, USA. Tel.: +1
857 334 3844; E-mail: alex_drakaki@hotmail.com
Abstract: The family of extra structurally abnormal chromosomes includes
supernumerary small chromosomes, which are related to developmental
abnormalities. The most common supernumerary index chromosome is inverted
duplicated chromosome 15. Two cytogenetic types of inv dup(15) marker
chromosomes have been described, each one having different phenotype.
Specifically, neurological disorders have been correlated with cytogenetic
description of dic(15)(q12 or q13) which contains the Prader-Willi syndrome and
Angelman syndrome critical euchromatin regions. On the other hand, cytogenetic
description of dic(15)q11 heterocromatin area does not contain the Prader-Willi
syndrome/Angelman syndrome critical region and children with this aberration
show a normal phenotype. Here, we present the first case of 22-month-boy with
cytogenetic description of dic(15)q11 and neurological problems. Specifically
the patient was admitted in our department for chromosomal evaluation due to
neurological problems. Diagnosis was confirmed by standard cytogenetic
techniques and fluorescent in situ hybridization analysis. In addition, we did
not identify any abnormal methylation pattern of the small nuclear
ribonucleoprotein polypeptide N (SNRPN) locus. The presence of neurological
problems in a case of dic(15)q11, suggests that probably imprinted or other
genes located in this area are deregulated and it will be interesting future
studies to analyze these regions for the presence of imprinted genes.
