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PubMed This is a summary of 18 peer-reviewed journal articles Updated
Pediatrics

Symptoms and Systemic Involvement in PKS

At a Glance

Pallister-Killian Syndrome (PKS) is a variable, multisystem disorder that primarily causes delayed development, intellectual disability, and low muscle tone. Common physical signs include rounded facial features, an enlarged tongue, and an increased risk of early-life seizures or congenital hernias.

Pallister-Killian Syndrome (PKS) is a multisystem disorder, meaning it can affect many different parts of the body at the same time [1][2]. Because PKS is so variable, no two children will have the exact same combination of symptoms. Understanding these characteristic features can help you and your care team monitor your child’s health and provide early support.

Craniofacial (Face and Head) Features

Many children with PKS share distinct facial characteristics that may become more noticeable over time [3].

  • Coarse Facies: This medical term refers to facial features that appear rounded or heavy [3][4].
  • High Forehead and Bitemporal Alopecia: Children often have a prominent forehead and thin hair or hair loss at the temples (alopecia) [1][4].
  • Macroglossia: An enlarged tongue, which can sometimes interfere with feeding or speech [3][4].
  • Wide-Set Eyes and Ears: You may notice hypertelorism (eyes spaced widely apart) and ears that are low-set or shaped differently [3][5].

Neurological Involvement

PKS significantly impacts the developing brain and nervous system [1].

  • Intellectual Disability and Developmental Delay: Most children experience significant delays in reaching milestones like sitting up, walking, and talking [1][6].
  • Hypotonia: This is often described as “floppiness” or low muscle tone, which can make physical movements more difficult [1].
  • Epilepsy and Seizures: Seizures are common and can begin early in life. These may include seizures triggered by light (photosensitivity) [7][6]. Crucially, parents should watch for Infantile Spasms, a severe seizure type that can look like normal startle reflexes, repetitive ‘jackknife’ movements, or severe reflux [6]. These require urgent neurological evaluation to prevent severe cognitive regression.
  • Brain Structure: Imaging (like an MRI) may show structural differences, such as polymicrogyria (too many small folds in the brain surface) or small areas of calcification [8][9].

Sensory Impairments

Significant deficits in hearing and vision are common in PKS and can profoundly impact early development [1].

  • Vision Issues: Many children have structural eye problems or Cortical Visual Impairment (CVI), where the brain has difficulty processing visual information [1].
  • Hearing Loss: Regular audiology evaluations are essential to detect and manage hearing loss early [1].

Systemic (Body-Wide) Involvement

Beyond the face and brain, PKS can involve other vital organs and systems [1][2].

  • Congenital Diaphragmatic Hernia (CDH): A hole in the diaphragm (the muscle that separates the chest from the belly) that allows abdominal organs to move into the chest cavity. This is a known risk in PKS and often requires surgical repair [10][11].
  • Sleep-Disordered Breathing: Many children have trouble breathing while asleep, which may include obstructive sleep apnea [12].
  • Skin Changes: You may see “patchy” skin, including areas with less color (hypopigmentation) that often follow swirling or streaky patterns known as the lines of Blaschko [13][14]. This specific pattern helps doctors identify genetic mosaicism.
  • Oro-dental Issues: Delayed tooth eruption, large gums, or a high-arched palate (the roof of the mouth) are common and require specialized dental care [15][5].

A Note on Variability

It is important to remember that PKS is highly variable [1][2]. While severe intellectual disability and significant developmental delays are the most common outcomes, there are rare, documented cases of individuals with PKS who have near-normal cognitive development [16][17]. Do not feel like you are doing something wrong if your child does not reach these rare exceptions; a child’s genetic report cannot predict exactly how severe their symptoms will be [18][8].

For next steps, see Building Your Care Team & First Visit Prep.

Common questions in this guide

What are the common facial features of a child with PKS?
Children with Pallister-Killian Syndrome often have rounded facial features, a prominent forehead with thin hair at the temples, an enlarged tongue, and wide-set eyes. These physical traits may become more noticeable as your child grows.
Do children with Pallister-Killian Syndrome have seizures?
Yes, seizures are very common in PKS and can start early in life. Parents should watch closely for infantile spasms, a severe type of seizure that can look like startle reflexes, sudden repetitive jerks, or severe reflux, which requires urgent medical evaluation.
How does PKS affect the brain and development?
Most children experience significant developmental delays and intellectual disability. They also frequently have low muscle tone, often described as 'floppiness,' which makes physical movements like holding up their head, sitting up, and walking more difficult.
What is a Congenital Diaphragmatic Hernia (CDH)?
A Congenital Diaphragmatic Hernia is a hole in the muscle separating the chest from the belly, allowing abdominal organs to move into the chest cavity. It is a known complication of PKS that often requires early surgical repair.
Does Pallister-Killian Syndrome cause sleep problems?
Many children with PKS experience sleep-disordered breathing, including obstructive sleep apnea. Your doctor may recommend a specialized sleep study to monitor and manage breathing issues during the night.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Has my child been screened for a Congenital Diaphragmatic Hernia (CDH), and what follow-up imaging might be needed?
  2. 2.Given the high risk of sleep-disordered breathing, should we schedule a sleep study (polysomnography)?
  3. 3.What types of seizures should I be watching for, and is a baseline EEG necessary?
  4. 4.Could you recommend a pediatric dentist who has experience with children who have macroglossia or delayed tooth eruption?
  5. 5.Can we review my child's brain imaging (MRI or CT) to see if there are structural findings like polymicrogyria or calcifications?

Questions For You

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References

References (18)
  1. 1

    A review of structural brain abnormalities in Pallister-Killian syndrome.

    Poulton C, Baynam G, Yates C, et al.

    Molecular genetics & genomic medicine 2018; (6(1)):92-98 doi:10.1002/mgg3.351.

    PMID: 29222831
  2. 2

    Pallister-Killian Mosaic Syndrome in an Omani Newborn: A Case Report and Literature Review.

    Elsheikh A, Al Shehhi M, Goud TM, et al.

    Oman medical journal 2019; (34(3)):249-253 doi:10.5001/omj.2019.47.

    PMID: 31110634
  3. 3

    Prenatally identified Pallister-Killian syndrome: Ultrasound pattern and diagnostic considerations.

    Santamaria A, Laganà AS, Barresi V, et al.

    Journal of obstetrics and gynaecology : the journal of the Institute of Obstetrics and Gynaecology 2016; (36(3)):406-7 doi:10.3109/01443615.2015.1086984.

    PMID: 26471928
  4. 4

    Clinical Variability of Pallister-Killian Syndrome in Two Egyptian Patients.

    Eid MM, Eid OM, Abdel-Hadi S, et al.

    Journal of pediatric genetics 2020; (9(3)):207-210 doi:10.1055/s-0039-3400489.

    PMID: 32714624
  5. 5

    Dental Treatment of a Child with Pallister-Killian Syndrome.

    Didinen S, Atabek D, Kip G, et al.

    Case reports in dentistry 2016; (2016()):4130961 doi:10.1155/2016/4130961.

    PMID: 26998367
  6. 6

    Myoclonic epilepsy with photosensitivity in infants with Pallister-Killian Syndrome.

    Ricci E, Bonfatti R, Rocca A, et al.

    European journal of paediatric neurology : EJPN : official journal of the European Paediatric Neurology Society 2019; (23(4)):653-656 doi:10.1016/j.ejpn.2019.05.012.

    PMID: 31178275
  7. 7

    Neuroimaging findings in Pallister-Killian syndrome.

    Barkovich EJ, Lateef TM, Whitehead MT

    The neuroradiology journal 2018; (31(4)):403-411 doi:10.1177/1971400917744798.

    PMID: 29260614
  8. 8

    Structural brain abnormalities in Pallister-Killian syndrome: a neuroimaging study of 31 children.

    Fetta A, Toni F, Pettenuzzo I, et al.

    Orphanet journal of rare diseases 2024; (19(1)):107 doi:10.1186/s13023-024-03065-5.

    PMID: 38459574
  9. 9

    Polymicrogyria with calcification in Pallister-Killian syndrome detected by microarray analysis.

    Hiraiwa A, Matsui K, Nakayama Y, et al.

    Brain & development 2021; (43(3)):448-453 doi:10.1016/j.braindev.2020.11.003.

    PMID: 33229101
  10. 10

    Congenital Diaphragmatic Hernia Repair in a Patient With Pallister-Killian Mosaic Syndrome and Left Ventricular Hypoplasia.

    Kostyk P, Salik I

    Cureus 2022; (14(3)):e23095 doi:10.7759/cureus.23095.

    PMID: 35464544
  11. 11

    [Prenatal and clinicopathological study of 6 cases of Pallister-Killian syndrome and review].

    Desseauve D, Legendre M, Dugué-Maréchaud M, et al.

    Gynecologie, obstetrique & fertilite 2016; (44(4)):200-6.

    PMID: 27032761
  12. 12

    Sleep in Children With Pallister Killian Syndrome: A Prospective Clinical and Videopolysomnographic Study.

    Fetta A, Di Pisa V, Ruscelli M, et al.

    Frontiers in neurology 2021; (12()):796828 doi:10.3389/fneur.2021.796828.

    PMID: 34975740
  13. 13

    Seizures and Cardiomyopathy in a Patient with Pallister-Killian Syndrome due to Hexasomy 12p Mosaicism.

    Toydemir RM, Panza E, Longhurst MC, et al.

    Molecular syndromology 2020; (11(3)):125-129 doi:10.1159/000507598.

    PMID: 32903844
  14. 14

    Trisomy 12p mosaicism syndrome in a patient with hypopigmented cutaneous mosaicism and three cell lines in peripheral blood.

    Porcar Saura S, Díaz Giménez M, Guillén-Climent S, et al.

    Journal of the European Academy of Dermatology and Venereology : JEADV 2023; (37(1)):e54-e58 doi:10.1111/jdv.18555.

    PMID: 35993792
  15. 15

    Oro-dental features of Pallister-Killian syndrome: Evaluation of 21 European probands.

    Bagattoni S, D'Alessandro G, Sadotti A, et al.

    American journal of medical genetics. Part A 2016; (170(9)):2357-64 doi:10.1002/ajmg.a.37815.

    PMID: 27354242
  16. 16

    Co-Occurrence of Pallister-Killian Syndrome and Burkitt Lymphoma in a Patient with Near-Normal Neurocognitive Development.

    Izumi K, Ganetzky RD, Wertheim GBW, et al.

    Molecular syndromology 2023; (14(4)):303-309 doi:10.1159/000530197.

    PMID: 37589028
  17. 17

    Case Report: A Case Study on the Neurodevelopmental Profile of a Child With Pallister-Killian Syndrome and His Unaffected Twin.

    Samango-Sprouse CA, Hamzik MP, Rosenbaum K, et al.

    Frontiers in pediatrics 2022; (10()):817133 doi:10.3389/fped.2022.817133.

    PMID: 35372156
  18. 18

    Pallister-Killian Syndrome: The Diagnosis is in the Detail.

    Sailer S, Díaz GA, García MH, et al.

    Klinische Padiatrie 2019; (231(2)):93-95 doi:10.1055/a-0781-2564.

    PMID: 30517961

This page describes common symptoms and systemic features of Pallister-Killian Syndrome for educational purposes. Always consult a pediatric specialist or geneticist for your child's specific diagnosis, evaluation, and care plan.

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