| Pallister-Killian syndrome | |
|---|---|
| ICD-10 | Q99.8 |
| ICD-9 | 758.5 |
| OMIM | 601803 |
The ICD code Q998 is used to code Pallister-Killian syndrome. Pallister–Killian syndrome (also tetrasomy 12p mosaicism or Pallister mosaic aneuploidy syndrome) is an extremely rare genetic disorder occurring in humans. Pallister-Killian occurs due to the presence of the anomalous extra isochromosome 12p, the short arm of the twelfth chromosome.
Provider unable to clinically determine whether the condition was present at the time of inpatient admission. Pallister–Killian syndrome (also tetrasomy 12p mosaicism or Pallister mosaic aneuploidy syndrome) is an extremely rare genetic disorder occurring in humans.
The Pallister-Killian syndrome is reliably diagnosed by FISH on buccal mucosa. Clin Dysmorphol. 2000;9(3):163–165. doi: 10.1097/00019605-200009030-00002. [ PubMed] [ CrossRef] [ Google Scholar]
Chiesa J, et al. Pallister-Killian syndrome [i (12p)]: first pre-natal diagnosis using cordocentesis in the second trimester confirmed by in situ hybridization. Clin Genet. 1998;54(4):294–302. doi: 10.1034/j.1399-0004.1998.5440406.x. [ PubMed] [ CrossRef] [ Google Scholar] 36. Fryns JP, et al. Mosaic tetrasomy 21 in severe mental handicap.
This condition 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.
This malformation can occur as an isolated finding, but in more than 30–50% of the cases there is an association with chromosomal anomalies, mainly trisomy 18 and tetrasomy 12p (Pallister–Killian syndrome) and other syndromic conditions (e.g. Fryns syndrome) (see Table 15-1) or with isolated organ defects (e.g. heart, ...
Signs and symptomsLarge forehead that is often broad.Depressed nasal bridge.Widely-spaced eyes (orbital hypertelorism), which may include droopy eyelids (ptosis)Low-set ears with thickened helices (top rim of the ear)Cupid's bow lip with extension of the phitral skin into the vermilion border (termed Pallister lip)More items...
One example of a rare genetic disorder of duplication is called Pallister Killian syndrome, where part of the #12 chromosome is duplicated.
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.
Chromosome 12, trisomy 12p, is an extremely rare chromosomal disorder in which a portion of the short arm of the 12th chromosome (12p) appears three times (trisomy) rather than twice in cells of the body.
Pallister-Killian syndrome is a chromosomal disorder caused by having an extra chromosome. It is not inherited and occurs spontaneously in a child by chance. All cases recorded to date have been sporadic.
Pallister-Killian mosaic syndrome can be diagnosed before birth (prenatally) by removing a small amount of fluid that is in the womb during pregnancy (amniocentesis) or by removing a small number of cells from outside the sac where the fetus develops (chorionic villous sampling).
Cornelia de Lange syndrome is genetic condition that is caused by mutations in at least five genes (NIPBL, RAD21, SMC3, HDAC8, and SMC1A). The severity of the condition can vary greatly depending on the type of mutation and which gene is affected. More than half of people with CdLS have mutations in the NIPBL gene.
The four main types of structural chromosomal aberrations are deletion, duplication, inversion, and translocation.
Deletions occur when a chromosome breaks and some genetic material is lost. Deletions can be large or small, and can occur anywhere along a chromosome. Duplications. Duplications occur when part of a chromosome is abnormally copied (duplicated).
Diagnostic testing: The diagnosis of PKS is made by physical examination and then confirmed by finding the presence of the extra genetic material of isochromosome 12p on a chromosome test.
Skeletal abnormalities (i.e., extra fingers/toes, and unusually short arms and legs).
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A number of cases are prenatally diagnosed because of abnormal ultrasonic findings, and abnormal presentation at birth is usual. Most common signs include facial dysmorphism, rhizomelic limb shortness, small hands and feet with nail hypoplasia.
Patients with PKS have mosaïcism for a supernumerary isochromosome 12p, resulting in four copies of the short arm of chromosome 12 instead of the normal two. The isochromosome is mostly of maternal origin. Selection against i (12p) cells is observed in vitro, and probably also occur in vivo. Karyotype is 47, XX or XY, i (12) (p10)/ 46,XX or XY.
Clinical recognition is very important as the additional chromosome is usually absent from routine blood lymphocytes examination. Cytogenetic diagnosis requires skin biopsy and fibroblast chromosome examination. The isochromosome is usually present in 30-100% of fibroblast metaphases.
Differential diagnoses include trisomy 12p and Fryns syndrome (see these terms). Antenatal diagnosis may be possible through ultrasound examination revealing abnormal findings such as diaphragmatic hernia, polyhydramnios, hydrops fetalis, cardiac malformations, short limbs, and other, leading to amniocentesis and chromosomal diagnosis.
Antenatal diagnosis is also possible after choriocentesis for maternal age.
There is no specific therapy. Affected children may benefit from early intervention programs and special education.
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. The signs and symptoms of Pallister-Killian mosaic syndrome can vary, although most documented cases of people with the syndrome have severe to profound intellectual disability and other serious health problems. [1]
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