Dup(8p)
Epidemiology and
Etiology:
- Olfactory
repeat regions REPD and REPP give rise to large rearrangements of the
interval between
Common sites:
Gross features:
- dup(8)(p23.1)
- mild dysmorphism
- characteristic
facies:
- prominent
forehead and arched eyebrows
- congenital
heart disease (ex. TOF) (variable)
-
Histologic
features:
Immunophenotype:
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Marker:
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Sensitivity:
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Specificity:
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Molecular features:
- dup(8)(p23.1):
- ~3.75Mb
duplication involving most of band 8p23.1 between REPP and REPD (ORDRs)
- contains
57 genes between them
- GATA4
is a cardiac transcription factor
- inv dup (8)(p23.1p___) (variable – from REPP
to up to centromere)
- supernumerary
marker chromosome
- 2
copies of the region distal to REPD inverted with respect to each other
- neocentromere formation at REPD site
- tandem
repeats of defensin genes
- may
look the same as dup (8)(p23.1) on light microscopy
Other features:
- dup(8)(p23.1):
- variable
mild developmental delay
- speech
delay
- some
live independent
lives with varying degrees of support
- somatic
increase in copy number at this site may lead to malignancies (but
breakpoints may not be the same):
- malignant fibrous histiocytoma (MFHAS1)
- esophageal
CA
References: