What is Tetrasomy 12p?
A child with Pallister-Killian syndrome has 47 chromosomes. This extra chromosome is made up of two copies of the short arm (p arm) of chromosome 12 in some cells of the body. In these cells, there are four copies of this 12p arm of chromosome 12, instead of the usual two copies. This is called tetrasomy 12p.
What does Pallister-Killian Syndrome do?
Pallister-Killian mosaic syndrome is a multi-system disorder that is characterized by extremely weak muscle tone ( hypotonia ) in infancy and early childhood, intellectual disability , distinctive facial features, sparse hair, areas of unusual skin coloring (pigmentation), and other birth defects .
How does Pallister-Killian Syndrome occur?
Pallister-Killian mosaic syndrome is usually caused by the presence of an abnormal extra chromosome called an isochromosome 12p or i(12p). An isochromosome is a chromosome with two identical arms. Normal chromosomes have one long (q) arm and one short (p) arm, but isochromosomes have either two q arms or two p arms.
How is Pallister-Killian Syndrome inherited?
Pallister-Killian mosaic syndrome is not inherited; the disorder is the result of a random event during the formation of reproductive cells, it usually occurs in the mother. Typically, an error in cell division (nondisjunction) causes a reproductive cell to contain an isochromosome 12p.
Is Sotos syndrome autism?
Telling traits: Children with Sotos syndrome have distinct facial features. Most people with Sotos syndrome show signs of autism, according to the largest-yet study of people with the rare genetic condition1. Sotos syndrome affects about 1 in 14,000 people.
What does chromosome 12 affect?
Other changes in the number or structure of chromosome 12 can have a variety of effects on health and development. These effects include intellectual disability, slow growth, distinctive facial features, weak muscle tone (hypotonia), skeletal abnormalities, and heart defects.
What is the life expectancy of someone with Sotos syndrome?
Sotos syndrome is not a life-threatening disorder and patients may have a normal life expectancy. The initial abnormalities of Sotos syndrome usually resolve as the growth rate becomes normal after the first few years of life.
What are Soto seizures?
Sotos syndrome (SS) is an overgrowth syndrome characterized by typical facial appearance, learning disability, and macrocephaly as cardinal diagnostic features. Febrile (FS) and afebrile seizures are reported in 9-50% of cases.
How do I know if my child has Williams syndrome?
Young children with Williams syndrome have distinctive facial features including a broad forehead, a short nose with a broad tip, full cheeks, and a wide mouth with full lips. Many affected people have dental problems such as teeth that are small, widely spaced, crooked, or missing.
Can a person with Williams syndrome live a normal life?
Most people with Williams syndrome have a normal life expectancy, but some may have a reduced life expectancy due to complications of the disease (such as cardiovascular problems).
What are the symptoms of trisomy 12?
Mosaic trisomy 12 is a rare chromosomal anomaly syndrome, with a highly variable phenotype, principally characterized by developmental or growth delay, short stature, craniofacial dysmorphism (e.g. turricephaly, tall forehead, downslanting palpebral fissures, posteriorly rotated and low set ears, narrow palate).
What is tetrasomy 12p?
This extra chromosome is made up of two copies of the short arm (p arm) of chromosome 12 in some cells of the body. In these cells, there are four copies of this 12p arm of chromosome 12, instead of the usual two copies. This is called tetrasomy 12p.
What is Pallister-Killian syndrome (tetrasomy 12p)?
Tetrasomy 12p (Pallister-Killian syndrome) is a mosaic aneuploidy syndrome in which the isochromosome is present in amniocytes with a much greater percentage than fetal lymphocytes. Two new cases identified by prenatal diagnosis are reported.
What is the isochromosome 12p?
(XX indicates female) +i There is an additional isochromosome (12p) The isochromosome is made from copies of the p arm of chromosome 12 [7] Of the 13 [7+6] cells examined, 7 were seen to contain the isochromosome /46 Some of the examined cells have 46 chromosomes i.e. a ‘normal’ chromosome count.
How many copies of chromosome 12 are in PKs?
In these cells, there are four copies of this 12p arm of chromosome 12, instead of the usual two copies. This is called tetrasomy 12p. PKS is a mosaic syndrome, meaning that an individual has the extra chromosomal material in some cells of the body, but not all.