PALLISTER-KILLIAN SYNDROME
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ALTERNATE NAMES
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Isochromosome 12p Syndrome; Killian Syndrome; Pallister-Killian Mosaic Syndrome; Pallister
Mosaic Syndrome; Teschler-Nicola/Killian Syndrome; Tetrasomy 12p Mosaic Syndrome;
Tetrasomy 12p Syndrome;
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DESCRIPTION
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Pallister-Killian
syndrome
(PKS) is a rare genetic disorder in which a person has four copies of the short arm of
chromosome 12 (isochromosome 12p), instead of the normal two copies. The extra genetic
material from isochromosome 12p disrupts the normal course of development, causing
the characteristic features of this disorder.
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DIAGNOSTIC TESTING, PHYSICAL FINDINGS, AND
ICD-9-CM/ICD-10-CM
CODING |
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.
Physical findings: Children with PKS have:
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Extremely weak muscle tone (hypotonia);
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Developmental delay/intellectual disability;
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Distinctive facial features;
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Sparse hair on the scalp;
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Abnormally wide space between the eyes;
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Extra skin folds over the corners of the eyes;
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High arched or cleft palate;
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Skeletal abnormalities (i.e., extra fingers/toes, and unusually short arms and legs).
ICD-9: 759.89
ICD-10: Q99.8
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PROGRESSION
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Onset is congenital. Many infants with PKS die before they are born (that is, in utero)
or soon after birth. Infants who survive birth have significant hypotonia, which can
cause difficulty breathing and problems with feeding. Hypotonia also interferes with
the normal development of motor skills, such as sitting, standing, and walking. About
30% of affected children are ultimately able to walk without assistance. Additional
developmental delays result from intellectual disability, which is usually severe
to profound. Speech is often limited or absent in children with this condition. About
40% of affected infants are born with a congenital diaphragmatic hernia, in which
there is an abnormal opening in the diaphragm (the muscle that separates the abdomen
from the chest cavity). This potentially serious birth defect allows the stomach and
intestines to move into the chest, where they can crowd the developing heart and lungs.
The physical manifestations of PKS progress with age. The prognosis for PKS is poor,
although several people have been identified with mild intellectual disability and
less obvious physical abnormalities.
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TREATMENT
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Treatment is dependent on the medical condition of the individual and the affected
organ defects. Affected school age children may benefit from early intervention programs
and special education.
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SUGGESTED PROGRAMMATIC ASSESSMENT*
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Suggested MER for Evaluation:
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Clinical history and examination that describes the diagnostic features of the impairment;
and
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Laboratory tests showing results of genetic testing (chromosomal analysis).
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Suggested Listings for Evaluation:
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DETERMINATION
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LISTING
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REMARKS
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Meets
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110.08
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Listing-level severity must be documented; evaluate under the most affected body systems.
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111.09
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Listing-level severity must be documented; evaluate under the most affected body systems.
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111.17
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Listing-level severity must be documented; evaluate under the most affected body systems.
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112.05
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Listing-level severity must be documented; evaluate under the most affected body systems.
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112.12
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Listing-level severity must be documented; evaluate under the most affected body systems.
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Equals
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* Adjudicators may, at their discretion, use the Medical Evidence of Record or the
listings suggested to evaluate the claim. However, the decision to allow or deny the
claim rests with the adjudicator.
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