Pallister-Killian syndrome: clinical, cytogenetic and molecular findings in 15 cases.

Background: Pallister Killian syndrome (PKS, OMIM 601803) is a rare genetic disorder with a distinct phenotype caused by tissue- limited mosaicism tetrasomy of the short arm of chromosome 12, which usually cytogenetically presents as an extra isochromosome 12p.Wide phenotypic variability in PKS has been reported, ranging from pre-to perinatal death due to multiple congenital anomalies, especially diaphragmatic hernia, and classic phenotypes including seizures, severe developmental delay, macrosomia at birth, deafness, and distinct dysmorphic features, such as coarse face, temporal alopecia, a small nose with anteverted nostrils, long philtrum, and hypo-/hyper- pigmented streaks on the skin.

Results: Karyotypes obtained from cultured peripheral lymphocytes of 13 cases, who were diagnosed as PKS, were normal, while karyotypes obtained from cultured skin samples and buccal mucosa revealed the supernumerary mosaic i(12p).

The identification of small supernumerary marker chromosomes; the experiences of 15,792 fetal karyotyping from Turkey.

Small supernumerary marker chromosomes (sSMCs) are often associated with developmental abnormalities and malformations are de novo in approximately 60% of the cases. Fluorescence in situ hybridization (FISH) techniques using various probes provided the possibility to analyze and characterize sSMCs, which is highly important for prenatal diagnosis and genetic counseling. We now present the establishment of a specific strategy to identify the origin and structure of the sSMCs using a combination of conventional banding and classical FISH techniques.

Homozygous and heterozygous inheritance of PAX3 mutations causes different types of Waardenburg syndrome.

Type I Waardenburg syndrome (WS-I) is an auditory-pigmentary syndrome caused by heterozygous loss of function mutations in the PAX3 gene. Klein-Waardenburg syndrome (WS-III) is a very rare condition and represents an extreme presentation of WS-I, additionally associated with musculoskeletal abnormalities. We present an 18-months old Turkish child with typical Klein-Waardenburg syndrome (WS) including dystopia canthorum, partial albinism, and upper-limb defects.