Linear nevus sebaceous syndrome

Title

Other Names:

Schimmelpenning Feuerstein Mims syndrome; Sebaceous nevus syndrome linear; SFM syndrome; Schimmelpenning Feuerstein Mims syndrome; Sebaceous nevus syndrome linear; SFM syndrome; Jadassohn nevus phakomatosis; JNP; Nevus sebaceus of Jadassohn; Organoid nevus phakomatosis See More

Categories:

Congenital and Genetic Diseases; Eye diseases; Rare Cancers; Congenital and Genetic Diseases; Eye diseases; Rare Cancers; Skin Diseases See More

Summary Summary

Linear nevus sebaceous syndrome (LNSS) is a condition characterized by the association of a large, linear sebaceous nevus (type of birthmark) with a broad range of abnormalities that may affect every organ system, including the central nervous system (CNS).^[1] The nevus usually is located on the face, scalp, or neck.^[1]^[2] The most common CNS abnormalities are intellectual disability, seizures, and hemimegalencephaly (abnormal enlargement of one side of the brain).^[1]^[2] Various other CNS abnormalities have been reported.^[2] Other signs and symptoms may include various eye abnormalities; skeletal (bone) deformities; heart defects; urogenital abnormalities; and an increased risk of cancer with age.^[1]^[3]^[4] LNSS is not inherited (it is sporadic). It can be caused by a somatic mutation in any of several genes. Mutations that cause LNSS occur after fertilization and are only present in some body cells (mosaicism).^[5] Treatment is directed towards the specific symptoms in each person.^[6]

Last updated: 1/4/2017

Symptoms Symptoms

Linear nevus sebaceous syndrome (LNSS) is characterized by the presence of a large, linear sebaceous nevus (type of birthmark usually present from birth) with a broad range of abnormalities that may affect every organ system, including the central nervous system (CNS).^[1] The specific symptoms and severity can vary greatly from one person to another.^[6]

The sebaceous nevus usually is located on the face, scalp, or neck.^[1]^[2] It can also be located on the arms, legs or trunk. While the nevus may be barely noticeable at birth, it typically becomes more pronounced with age (usually around puberty) and may appear scaly, warty or thickened. It typically does not cause any symptoms.^[6]

A variety of CNS abnormalities have been reported in people with LNSS. The most common are intellectual disability, seizures, and hemimegalencephaly (abnormal enlargement of one side of the brain).^[1]^[2] Other reported CNS abnormalities include:^[6]

Dandy-Walker malformation
abnormal formation of certain brain vessels
agenesis of the corpus callosum (absence of nerve tissue that connects the two sides of the brain)
defects of the folds of the brain, such as a lack of folds (agyria), small folds (microgyria) or thickened folds (pachygyria).

Other signs and symptoms of LNSS may include:^[1]^[6]^[2]

ophthalmologic (eye) abnormalities such as "crossed eyes" (strabismus), retinal anomalies, coloboma, cataracts, or ocular hemangiomas
skeletal (bone) abnormalities such as cranial fibrous dysplasia, skeletal hypoplasia (incomplete formation of bones), formation of bony structures, scoliosis, or vitamin D-resistant rickets or hypophosphatemia
heart defects such as narrowing of the aorta (aortic coarctation)
urogenital abnormalities such as a horseshoe kidney
an increased risk of cancer with age

Last updated: 1/4/2017

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.

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Medical Terms	Other Names	Learn More: HPO ID
80%-99% of people have these symptoms
Adenoma sebaceum		0009720
Alopecia	Hair loss	0001596
Aplasia/Hypoplasia of the cerebellum	Absent/small cerebellum Absent/underdeveloped cerebellum [ more ]	0007360
Asymmetric growth	Uneven or disproportionate growth of one body part compared to another	0100555
Biparietal narrowing		0004422
Cavernous hemangioma	Collection of dilated blood vessels that forms mass	0001048
EEG abnormality		0002353
Frontal bossing		0002007
Genu recurvatum	Back knee Knee hyperextension [ more ]	0002816
Hyperreflexia	Increased reflexes	0001347
Intellectual disability	Mental deficiency Mental retardation Mental retardation, nonspecific Mental-retardation [ more ]	0001249
Iris coloboma	Cat eye	0000612
Melanocytic nevus	Beauty mark	0000995
Microphthalmia	Abnormally small eyeball	0000568
Muscular hypotonia	Low or weak muscle tone	0001252
Prominent occiput	Prominent back of the skull Prominent posterior skull [ more ]	0000269
Reduced tendon reflexes		0001315
Seizures	Seizure	0001250
Telecanthus	Corners of eye widely separated	0000506
Vertebral segmentation defect		0003422
30%-79% of people have these symptoms
Abnormality of vision	Abnormality of sight Vision issue [ more ]	0000504
Facial asymmetry	Asymmetry of face Crooked face Unsymmetrical face [ more ]	0000324
Irregular hyperpigmentation		0007400
Plagiocephaly	Flat head syndrome Flattening of skull Rhomboid shaped skull [ more ]	0001357
Porencephalic cyst	Cavity within brain	0002132
5%-29% of people have these symptoms
Aplasia/Hypoplasia of the corpus callosum		0007370
Cerebral calcification	Abnormal deposits of calcium in the brain	0002514
Corneal opacity		0007957
Dandy-Walker malformation		0001305
Growth delay	Delayed growth Growth deficiency Growth failure Growth retardation Poor growth Retarded growth [ more ]	0001510
Hyperphosphaturia	High urine phosphate levels	0003109
Ophthalmoplegia	Eye muscle paralysis	0000602
Precocious puberty	Early onset of puberty Early puberty [ more ]	0000826
Percent of people who have these symptoms is not available through HPO
Abnormality of dental color	Abnormality of tooth color Abnormality of tooth shade [ more ]	0011073
Abnormality of dental morphology	Abnormality of dental shape Abnormally shaped teeth Deformity of teeth Dental deformity Dental malformations Malformed teeth Misshapen teeth Misshapened teeth [ more ]	0006482
Abnormality of finger	Abnormalities of the fingers	0001167
Abnormality of toe	Abnormalities of the toes	0001780
Basal cell carcinoma		0002671
Coarctation of aorta	Narrowing of aorta Narrowing of the aorta [ more ]	0001680
Coloboma	Notched pupil	0000589
Cranial asymmetry		0000267
Hemangioma	Strawberry mark	0001028
Hemihypertrophy	Asymmetric overgrowth	0001528
Hemimegalencephaly		0007206
Horseshoe kidney	Horseshoe kidneys	0000085
Hypophosphatemic rickets		0004912
Hypopigmentation of the skin	Patchy lightened skin	0001010
Ichthyosis		0008064
Kyphoscoliosis		0002751
Linear nevus sebaceous		0010817
Nevus sebaceous		0010815
Osteopenia		0000938
Overgrowth	General overgrowth	0001548
Recurrent fractures	Increased fracture rate Increased fractures Multiple fractures Multiple spontaneous fractures Varying degree of multiple fractures [ more ]	0002757
Short stature	Decreased body height Small stature [ more ]	0004322
Somatic mosaicism		0001442
Sporadic	No previous family history	0003745

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Last updated: 10/1/2019

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Cause Cause

Linear nevus sebaceous syndrome (LNSS) can be caused by a somatic mutation in any of several genes, including the HRAS, KRAS and NRAS genes.^[5] Mutations that cause LNSS occur after fertilization (they are not inherited) and are only present in some body cells (mosaicism).^[5] These three genes belong to a class of genes called oncogenes, which when mutated, have the potential to cause normal cells to become cancerous. They play important roles in cell division, cell differentiation (the process by which cells learn to do specific "jobs") and the self-destruction of cells (apoptosis).^[7]

Somatic mutations in several genes, including HRAS and KRAS, are responsible for causing isolated nevus sebaceous.^[5] It is thought that the additional signs and symptoms in people with LNSS occur because the somatic mutation affects other tissues in addition to the skin.^[7] While it is unclear exactly how mutations cause the additional symptoms of LNSS, it may relate to disrupted regulation of cell growth and division.

Last updated: 1/5/2017

Inheritance Inheritance

Linear nevus sebaceous syndrome (LNSS) is not inherited. All cases reported have been sporadic, occurring by chance in people with no family history of the condition.^[5] While LNSS is caused by genetic mutations, these mutations occur after fertilization in the affected person. They are not present in a parent's egg or sperm.

Last updated: 1/5/2017

Diagnosis Diagnosis

A diagnosis of linear nevus sebaceous syndrome (LNSS) is made by identifying the characteristic symptoms, which include a sebaceous nevus along with abnormalities affecting other organ systems.^[6]

Because of the potential for multi-system involvement, anyone suspected of having LNSS should have a number of evaluations to determine the presence and extent of associated symptoms. These may include:^[1]^[6]

imaging studies such as CT scan or MRI of the brain (some researchers think these should be avoided unless there are signs of central nervous system involvement)
an electroencephalogram if epilepsy is present
analysis of skin biopsies
a complete ophthalmic (eye) exam
a skeletal survey
chests x-rays

Last updated: 1/4/2017

Treatment Treatment

Treatment for linear nevus sebaceous syndrome (LNSS) is directed towards the specific symptoms and severity in each affected person. Management may require coordinated efforts of a team of specialists that may consist of pediatricians, pediatric neurologists, dermatologists, orthopedists, ophthalmologists, and other healthcare professionals.

Those who are concerned about cosmetic appearance regarding the nevus might consider surgery to remove the nevus. Surgery used to be recommended due to the risk of becoming cancerous (malignant); however, the risk of malignancy is now much less than previously believed. Surgical removal of the nevus may not always be possible due to its specific location.

Additional treatments depend on the specific abnormalities present and usually follow standard guidelines in the general population for these abnormalities. For example, epilepsy may be treated with anti-seizure medications.^[6]

Last updated: 1/5/2017

Find a Specialist Find a Specialist

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by the American College of Medical Genetics and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from Genetics Home Reference.

Related Diseases 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 diagnosis should include nevus comedonicus syndrome, Becker nevus syndrome, phakomatosis pigmentokeratotica, Proteus syndrome and CHILD syndrome (see these terms). Visit the Orphanet disease page for more information.

Research Research

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Patient Registry

A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with Linear nevus sebaceous syndrome. The type of data collected can vary from registry to registry and is based on the goals and purpose of that registry. Some registries collect contact information while others collect more detailed medical information. Learn more about registries.

Registries for Linear nevus sebaceous syndrome:
The National Registry for Ichthyosis & Related Skin Disorders

Organizations 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

Foundation for Ichthyosis and Related Skin Types (FIRST)
2616 North Broad Street
Colmar, PA 18915
Toll-free: 1-800-545-3286
Telephone: +1-215-997-9400
E-mail: info@firstskinfoundation.org
Website: http://www.firstskinfoundation.org/
Nevus Network
PO Box 305
West Salem, OH 44287
Telephone: (419) 853-4525 or (405) 377-3403
E-mail: info@nevusnetwork.org
Website: http://www.nevusnetwork.org
Nevus Outreach, Inc.
600 SE Delaware Ave., Suite 200
Bartlesville, OK 74003
Telephone: +1-918-331-0595
E-mail: https://www.nevus.org/contact-nevus-outreach
Website: https://www.nevus.org
The Skin Cancer Foundation
149 Madison Avenue Suite 901
New York, NY 10016
Telephone: 212-725-5176
Website: http://www.skincancer.org/

Do you know of an organization? We want to hear from you.

Learn More 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

The New Zealand Dermatolgical Society's Web site has information on nevus sebaceous, including information on linear nevus sebaceous syndrome. Click on the link above to view this information page.
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.

In-Depth Information

Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
MeSH® (Medical Subject Headings) is a terminology tool used by the National Library of Medicine. Click on the link to view information on this topic.
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 Linear nevus sebaceous syndrome. Click on the link to view a sample search on this topic.

GARD Answers GARD Answers

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At what age does a child get symptoms of sebaceous nevus? See answer
I was wondering if you could provide me with more information on linear sebaceous nevus syndrome. My son was diagnosed with this and I am having a real hard time finding information on it. See answer

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References References

Shay Menascu. Linear nevus sebaceus syndrome. Orphanet. June, 2008; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=2612.
Pauline L, Kannan B, Saravannan V, Eswaradass VP. Linear nevus sebaceous syndrome. Ann Indian Acad Neurol. October, 2014; 17(4):468-469.
Terenzi V, Indrizzi E, Buonaccorsi S, Leonardi A, Pellacchia V, Fini G.. Nevus sebaceus of Jadassohn. J Craniofac Surg. 2006; http://www.ncbi.nlm.nih.gov/pubmed/17119437.
Santibanez-Gallerani A, Marshall D, Duarte AM, Melnick SJ, Thaller S.. Should nevus sebaceus of Jadassohn in children be excised? A study of 757 cases, and literature review. J Craniofac Surg. 2003; http://www.ncbi.nlm.nih.gov/pubmed/14501324.
Ada Hamosh. SCHIMMELPENNING-FEUERSTEIN-MIMS SYNDROME; SFM. OMIM. November 24, 2014; https://www.omim.org/entry/163200.
Schimmelpenning Syndrome. NORD. 2015; https://rarediseases.org/rare-diseases/schimmelpenning-syndrome/.
HRAS gene. Genetics Home Reference. August, 2016; https://ghr.nlm.nih.gov/gene/HRAS.