Euchromatic variant 16p+. Implications in prenatal diagnosis.
BACKGROUND
Euchromatic imbalances at the cytogenetic level are usually associated with phenotypic consequences. Among the exceptions are euchromatic variants of chromosome 16 (16p+) with normal phenotype. There is a growing list of euchromatic duplications and deletions involving both G-positive and G-negative bands that seem to be phenotypically neutral, but these euchromatic variants are rare.


OBJECTIVE
The aim of this report is to describe a new familial case of euchromatic variant 16p+ and to emphasise the misinterpretation of these rare euchromatic variants particularly when ascertained at prenatal diagnosis.


RESULTS
Fluorescence in situ hybridisation with clone RP11-261A7 showed an amplified signal in the larger chromosome 16. This clone contains FLJ43855 gene, similar to sodium- and chloride-dependent creatine transporter.


CONCLUSIONS
So, this 16p+ variant that involves amplification of pseudogenetic sequences is considered a polymorphism in normal individuals.
López Pajares
I
I
Department of Medical Genetics, Hospital Universitario La Paz, Madrid, Spain.
Villa
O
O
Salido
M
M
Mori
M A
MA
Gonzalez
A
A
Lapunzina
P
P
De Torres
M L
ML
Vallcorba
I
I
Palomares
M
M
Fernández
L
L
Delicado
A
A
D000328:Adult; D002869:Chromosome Aberrations / Q000196:embryology; D025063:Chromosome Disorders / Q000175:diagnosis* / Q000196:embryology*; D002885:Chromosomes, Human, Pair 16; D022041:Euchromatin / Q000302:isolation & purification; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*
D022041:Euchromatin