del(8)(p23.1)

Epidemiology and Etiology:

· Olfactory repeat regions REPD and REPP give rise to large rearrangements of the interval between

· Deletion results from ectopic recombination (non-allelic homologous recombination – NAHR) between REPP and REPD

Common sites:

· Small terminal deletions

· Del(8)(p23.1)

Gross features:

· Heart defects frequently

· AVSD typically

· Conotruncal anomalies

· Pulmonary valve stenosis

· PDA

· Persistent left SVC

· Microcephaly

· hypospadias

Histologic features:

·

Immunophenotype:

Marker:

Sensitivity:

Specificity:

Molecular features:

· GATA4 (p23.1)

· Cardiac transcription factor

· May be the basis for frequent heart defects

Other features:

· IUGR

· Developmental delay

· Mild mental retardation

· Severe behavioural disturbance in childhood

· Sudden and extreme changes in behavior

· Outbursts of aggressiveness and destructiveness

· Very low frustration tolerance

· Improves in later adolescence

· Reduction in copy number of ORDRs themselves (3 copies or less – normal 2-7) may predispose to Crohn disease

· seizures

References:

· Gardner RJM, Sutherland GR. Chromosome Abnormalities and Genetic Counseling. 2nd ed. Oxford University Press, USA; 1996:496.