Pallister-Killian Syndrome
DESCRIPTION
Pallister-Killian Syndrome can also be found with the following Synonyms:
- Chromosome 12, Isochromosome 12p Mosaic
- Killian Syndrome
- Killian/Teschler-Nicola Syndrome
- Pallister Mosaic Syndrome
- Pallister Mosaic Syndrome Tetrasomy 12p
According to the NORD (National Organization for Rare Disorders)
Pallister-Killian Mosaic Syndrome is a rare chromosomal disorder that occurs for no apparent reason. Major symptoms may include a coarse face with a high forehead, sparse hair on the scalp, an abnormally wide space between the eyes, a fold of the skin over the inner corner of the eyes, and a broad nasal bridge with a highly arched palate. Mental retardation, loss of muscle tone, and streaks of skin lacking color are often present.
SYMPTOMS:
Patients with Pallister-Killian Mosaic Syndrome typically have low muscle tone at birth, sparse scalp hair at birth, a high forehead, a coarse face, an abnormally wide space between the eyes, a broad nasal bridge, a highly arched palate, a fold of the skin over the inner corner of the eyes, and large ears with lobes that are thick and protrude outward.
Other features frequently found in patients with this disorder may include: streaks of skin in which there is no color (hypopigmentation), extra nipples, seizures at birth, droopy upper eyelids, crossed eyes (strabismus), joints that will not move (contractures), and delays in perceiving, recognizing, judging, sensing, reasoning or imagining (cognitive delays).
Congenital heart defects, hernia's of the diaphragm, a narrowing of the external auditory canal (stenosis) and an abnormal opening in the anus have also been associated with Pallister-Killian Mosaic Syndrome.
CAUSES:
Pallister-Killian Mosaic Syndrome is caused by tetrasomy for chromosome 12p. Patients with Pallister-Killian Mosaic Syndrome have four copies of the short arm of chromosome 12 instead of the normal two. All recorded cases of this disorder have been sporadic (not believed to be hereditary).
Other details are reported by PedBase (Pediatric Database):
PATHOGENESIS:
Also called Killian/Teschler-Nicola Syndrome, Pallister Mosaic Syndrome, Tetrasomy 12p, Killian Syndrome, Teschler-Nicola/ Killian Syndrome the phenotypic features are due to the presence of four copies of chromosome 12p in affected cells the presence of the isochromosome 12p gives 4 copies of chromosome 12p in the affected cells
CLINICAL FEATURES:
1. Neurological Manifestations
- profound hypotonia at birth which persists
- seizures usually beginning in infancy
- developmental delay
- hypotonia with joint contractures developing between 5-10 years of age
- minimal speech development
- mental retardation (usually profound)
- sensorineuronal hearing loss
2. Craniofacial Features
- bitemporal sparsity of scalp hair which grows in by 2-5 years
- sparse eyebrows and eyelashes
- prominent high forehead
- progressive coarsening of the facies
- prominent cheeks
- large ears with thick protruding lobules
- eyes:
- hypertelorism
- epicanthal folds
- upslanting palpebral fissures
- strabismus
- ptosis
- nose:
- flattened nasal bridge
- short nose
- anteverted nares
- mouth:
- high-arched palate
- long philtrum with thin upper lip with a cupid-bow shape
- protruding lower lip
- delayed dental eruption
3. Others
- failure to thrive
- postnatal deceleration of length and head circumference
- generalized pigmentary dysplasia
- sparse hypopigmented macules
- streaks of hyper- and hypopigmentation
- accessory nipples
- laryngomalacia
- gastroesophageal reflux (up to 6 months)
- cataracts
- congenital heart defects
- diaphragmatic hernia
Last update: 27 March 2002
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