CEP17 SISH Ploidy Analysis

Result: DIPLOID

Original block *** results:

Interpretation:

A diploid DNA content is most frequently associated with a hydropic abortus. Diploidy can also be associated with a complete hydatidiform molar pregnancy. Correlation with clinical findings and morphology is recommended.

Scoring Guidelines (Galea et al):

Average number of signals per nucleus (ASN):

ASN<2.3 = diploid

ASN>/=2.3 = triploid

Percentage of nuclei with three signals (N3S):

N3S <33.6 = diploid

N3S>/=33.6 = triploid

CEP17 signals are enumerated at 400x magnification in villous stromal cells, and/or cytotrophoblast, and/or syncytiotrophoblast. Overlapping and incomplete nuclei should be avoided. The number of signals per nucleus should be counted in 50 nuclei in at least five different fields if possible. Nuclei with the highest number of signals should be preferentially counted. The total number of signals in 50 nuclei divided by 50 gives the average number of signals per nucleus (ASN). The total number of nuclei showing three signals divided by 50 gives the percentage of cells with three signals (N3S). Internal diploid control: maternal decidua.

Cutoff scores for ASN and N3S were selected as mean – 3 standard deviations; >99.7% of triploid scores are expected to be above the cutoff. Trisomy 17 is a rare trisomy (1/132 spontaneous abortions under 12 weeks gestation age) which could result in a false positive triploid interpretation (Horiuchi et al).

Methodology:

Ventana Inform Chromosome 17 probe

References:

1. Galea et al. Development of a silver in situ hybridization assay for the determination of ploidy status in molar pregnancy diagnosis. Pathology. 2014. 46 (1):15-20.

2. Horiuchi et al. Cytogenetic Analysis of Spontaneous Miscarriages Using Long Term Culturing of Chorionic Villi. J, Fetal Medicine. 2019. 6:1-6.

Test ID: MOLARCEP17

''MOLARCEP17''