Pallister Killian syndrome

Dr Jeremy Jones and Radswiki et al.

Pallister-Killian syndrome (PKS) is an extremly rare chromosomal anomaly.

It may be more prevalent in woman of advanced age 4.

It is a polymalformative complex with tetrasomy of isochromosome 12p although many cases are mosaic.

Genetics

The majority of cases are through to be sporadic but in some cases, the degree of mosaicism in the chorion villus sample is much more lower than that in the fetal tissues subsequently examined. Confined placental mosaicism is a well-recognized phenomenon in a number of chromosomal abnormalities and is said to contribute to their intra-uterine survival.

Tetrasomy 12p is not always diagnosed, because the tissues are differently affected. Although it is present in a high percentage of fibroblasts, it is practically absent from the blood.

Phenotypic expression can siginifcantly vary from multiple anomalies resulting in perinatal death to the more characteristic situation of

Other anomalies include

The mosiac forms make diagnosis difficult

Antenatal ultrasound

May show a comibation of some of the above clinical features. There may be polyhydramnios as an ancillary sonographic feature 2.

Some of the clinical features can overlap with the Fryns syndrome 1

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Article information

rID: 15073
Synonyms or Alternate Spellings:
  • Pallister-Killian syndrome
  • 12p tetrasomy
  • Tetrasomy 12p
  • Pallister Killian syndrome (PKS)

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