Pallister-Killian syndrome [i(12p)]: first pre-natal diagnosis using cordocentesis in the second trimester confirmed by in situ hybridization
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Published on: October 20, 2019
J Chiesa1, M Hoffet, O Rousseau
1Laboratoire de Biologie Cellulaire et de Cytogénétique Moléculaire, UPRES JE 1952, Faculté de Médecine, Université Montpellier I, France.
Insights
Pallister Killian syndrome (PKS), a mosaic isochromosome 12p condition, was diagnosed pre-natally using fetal blood cells and FISH. Consistent ultrasound findings aid in early PKS recognition.
Area of Science:
- Genetics
- Prenatal Diagnosis
- Human Malformations
Background:
- Pallister Killian syndrome (PKS) is characterized by mosaicism for an extra isochromosome 12p (i(12p)).
- Early and accurate diagnosis is crucial for managing PKS.
Observation:
- This study reports the first prenatal diagnosis of PKS using fetal blood cells obtained via second-trimester cordocentesis.
- In situ hybridization and fluorescence in situ hybridization (FISH) were employed to detect the i(12p) in fetal cells.
Findings:
- FISH analysis confirmed the presence of i(12p) in a mosaic pattern.
- A literature review identified 27 prenatal PKS cases, correlating specific ultrasound findings with the condition.
- Consistent prenatal ultrasound markers for PKS include hypertelorism, broad neck, short limbs, limb abnormalities, diaphragmatic hernia, and hydramnios.
Implications:
- Prenatal diagnosis of PKS is feasible using cordocentesis and cytogenetic analysis.
- Recognizing characteristic ultrasound findings can prompt further investigation with FISH for i(12p).
- Early PKS detection allows for timely genetic counseling and planning for affected infants.
Abstract:
Pallister Killian syndrome (PKS) is the most frequent form of partial autosomal tetrasomy 12p in humans. Sufferers have a mosaic of isochromosome 12p [i(12p)]. We report the first pre-natal diagnosis on fetal blood cells after cordocentesis during the second trimester. The extra chromosome was first diagnosed by in situ hybridization. Fluorescence in situ hybridization (FISH) was used to count the interphase and/or metaphase cells containing the isochromosome. A review of the literature identified 27 other reports of PKS diagnosed pre-natally. We showed that the most consistent pre-natal ultrasound findings include hypertelorism, broad neck, shorts limbs, abnormal hands or feet, diaphragmatic hernia and hydramnios. Recognition of this congenital malformation pattern pre-natally may allow utilization of FISH.
