Pallister-Killian mosaic syndrome

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Disease Profile

Unknown

US Estimated

Europe Estimated

Age of onset

Neonatal

ICD-10

Q99.8

Inheritance

Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.

X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.

Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

Not applicable

Other names (AKA)

Chromosome 12, Isochromosome 12p syndrome; Killian syndrome; Killian Teschler-Nicola syndrome;

Summary

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]

Pallister-Killian mosaic syndrome is usually caused by the presence of an abnormal extra chromosome 12 called isochromosome 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. Isochromosome 12p is a version of chromosome 12 made up of two p arms. Cells normally have two copies of each chromosome, one inherited from each parent. In people with Pallister-Killian mosaic syndrome, cells have the two usual copies of chromosome 12, but some cells also have the isochromosome 12p. These cells have a total of four copies of all the genes on the p arm of chromosome 12. The extra genetic material from the isochromosome disrupts the normal course of development, causing the characteristic features of this disorder.^[1]

Although Pallister-Killian mosaic syndrome is usually caused by an isochromosome 12p, other, more complex chromosomal changes involving chromosome 12 are responsible for the disorder in rare cases.^[1]

Treatment depends upon the specific symptoms present in each individual. Treating medical and developmental problems early can help to optimize outcome.^[2]

Symptoms

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms

Other Names

Learn More:

HPO ID

80%-99% of people have these symptoms

Cachexia

Wasting syndrome

0004326

Delayed eruption of teeth

Delayed eruption

Delayed teeth eruption

Delayed tooth eruption

Eruption, delayed

Late eruption of teeth

Late tooth eruption

[ more ]

0000684

Delayed skeletal maturation

Delayed bone maturation

Delayed skeletal development

[ more ]

0002750

Downturned corners of mouth

Downturned corners of the mouth

Downturned mouth

[ more ]

0002714

Everted lower lip vermilion

Drooping lower lip

Outward turned lower lip

[ more ]

0000232

Hypohidrosis

Decreased ability to sweat

Decreased sweating

Sweating, decreased

[ more ]

0000966

Intellectual disability, severe

Early and severe mental retardation

Mental retardation, severe

Severe mental retardation

[ more ]

0010864

Joint hyperflexibility

Joints move beyond expected range of motion

0005692

Long philtrum

0000343

Muscular hypotonia

Low or weak muscle tone

0001252

Ptosis

Drooping upper eyelid

0000508

Reduced tendon reflexes

0001315

Short neck

Decreased length of neck

0000470

Short stature

Decreased body height

Small stature

[ more ]

0004322

Sparse and thin eyebrow

Thin, sparse eyebrows

0000535

Sparse hair

0008070

Thick upper lip vermilion

Full upper lip

Increased volume of upper lip

Plump upper lip

Prominent upper lip

Thick upper lip

[ more ]

0000215

Thin upper lip vermilion

Thin upper lip

0000219

30%-79% of people have these symptoms

Anteverted nares

Nasal tip, upturned

Upturned nasal tip

Upturned nose

Upturned nostrils

[ more ]

0000463

Coarse facial features

Coarse facial appearance

0000280

Frontal bossing

0002007

Hypertelorism

Wide-set eyes

Widely spaced eyes

[ more ]

0000316

Prominent forehead

Pronounced forehead

Protruding forehead

[ more ]

0011220

Short nose

Decreased length of nose

Shortened nose

[ more ]

0003196

Telecanthus

Corners of eye widely separated

0000506

Upslanted palpebral fissure

Upward slanting of the opening between the eyelids

0000582

5%-29% of people have these symptoms

Abnormal soft palate morphology

0100736

Anal atresia

Absent anus

0002023

Strabismus

Cross-eyed

Squint

Squint eyes

[ more ]

0000486

Percent of people who have these symptoms is not available through HPO

Anal stenosis

Narrowing of anal opening

0002025

Anhidrosis

Lack of sweating

Sweating dysfunction

[ more ]

0000970

Anteriorly placed anus

0001545

Aortic valve stenosis

Narrowing of aortic valve

0001650

Aplasia of the upper vagina

Absent upper vagina

0012673

Aplasia of the uterus

Absent uterus

uterus absent

[ more ]

0000151

Atrial septal defect

An opening in the wall separating the top two chambers of the heart

Hole in heart wall separating two upper heart chambers

[ more ]

0001631

Bifid uvula

0000193

Broad foot

Broad feet

Wide foot

[ more ]

0001769

Broad palm

Broad hand

Broad hands

Wide palm

[ more ]

0001169

Cataract

Clouding of the lens of the eye

Cloudy lens

[ more ]

0000518

Clinodactyly of the 5th finger

Permanent curving of the pinkie finger

0004209

Coarctation of aorta

Narrowing of aorta

Narrowing of the aorta

[ more ]

0001680

Congenital diaphragmatic hernia

0000776

Congenital hip dislocation

Dislocated hip since birth

0001374

Cryptorchidism

Undescended testes

Undescended testis

[ more ]

0000028

Depressed nasal bridge

Depressed bridge of nose

Flat bridge of nose

Flat nasal bridge

Flat, nasal bridge

Flattened nasal bridge

Low nasal bridge

Low nasal root

[ more ]

0005280

Epicanthus

Eye folds

Prominent eye folds

[ more ]

0000286

Feeding difficulties

Feeding problems

Poor feeding

[ more ]

0011968

Flexion contracture

Flexed joint that cannot be straightened

0001371

Full cheeks

Apple cheeks

Big cheeks

Increased size of cheeks

Large cheeks

[ more ]

0000293

Generalized hypotonia

Decreased muscle tone

Low muscle tone

[ more ]

0001290

Hearing impairment

Deafness

Hearing defect

[ more ]

0000365

Hyperpigmented streaks

0007572

Hypertonia

Diagnosis

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

Orphanet lists international laboratories offering diagnostic testing for this condition.

Related diseases

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
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. Visit the Orphanet disease page for more information.

Organizations

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Chromosome Disorder Outreach (CDO)
PO Box 724
Boca Raton, FL 33429
Telephone: +1-561-395-4252
E-mail: https://chromodisorder.org/contact/
Website: https://chromodisorder.org/
PKS Kids
PO Box 12211
Green Bay, WI 54307
E-mail: gpeters@pkskids.net
Website: https://www.pkskids.net
Unique – Rare Chromosome Disorder Support Group
G1, The Stables
Station Road West
Surrey
RH8 9EE
United Kingdom
Telephone: +44 (0)1883 723356
E-mail: info@rarechromo.org
Website: https://www.rarechromo.org/

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

Genetics Home Reference (GHR) contains information on Pallister-Killian mosaic syndrome. This website is maintained by the National Library of Medicine.
The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.
Unique is a source of information and support for families and individuals affected by rare chromosome disorders. Click on the link to view information about Pallister-Killian mosaic syndrome.

In-Depth Information

The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine.
Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
PubMed is a searchable database of medical literature and lists journal articles that discuss Pallister-Killian mosaic syndrome. Click on the link to view a sample search on this topic.

References

Pallister-Killian mosaic syndrome. Genetics Home Reference. June 2016; https://ghr.nlm.nih.gov/condition/pallister-killian-mosaic-syndrome.
Dr. Ian Krantz. Recommended Clinical Evaluations for the Child with PKS. PKS Kids. 2015; https://www.pkskids.net/PKSClinicalRecomendations2012-08.pdf.

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Rare Psychiatry News

Neonatal

Q99.8

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.

Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.

X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.

Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

Not applicable

Other names (AKA)

Categories

Summary

Symptoms

Diagnosis

Testing Resources

Organizations

Organizations Supporting this Disease

Learn more

Where to Start

In-Depth Information

References

Rare Psychiatry News

Rare Psychiatry News

Neonatal

Q99.8

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.

Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.

X-linked dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

X-linked recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.

Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

Not applicable

Other names (AKA)

Categories

Summary

Symptoms

Diagnosis

Testing Resources

Related diseases

Organizations

Organizations Supporting this Disease

Learn more

Where to Start

In-Depth Information

References

X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.