X-linked ichthyosis: Difference between revisions

From WikiMD's Wellness Encyclopedia

No edit summary
Tag: visualeditor-wikitext
 
CSV import
 
(4 intermediate revisions by the same user not shown)
Line 1: Line 1:
==Other Names==
{{SI}}
Steroid sulfatase deficiency; SSD; SSDD; Steroid sulfatase deficiency disease; Placental steroid sulfatase deficiency; X linked ichthyosis
{{Infobox medical condition
[[File:IchthyosisXlinked2.JPG|thumb|right|X linked ichthyosis - this boy has an infant brother and maternal uncle with the same affliction]]
| name            = X-linked ichthyosis
 
| image          = [[File:X-linked_recessive.svg|200px]]
<youtube>
| caption        = X-linked recessive pattern
title='''{{PAGENAME}}'''
| synonyms        = Steroid sulfatase deficiency
movie_url=http://www.youtube.com/v/gfrtR9oBVgI
| pronounce      =
&rel=1
| specialty      = [[Dermatology]], [[Genetics]]
embed_source_url=http://www.youtube.com/v/gfrtR9oBVgI
| symptoms        = [[Dry skin]], [[scaling]], [[corneal opacities]]
&rel=1
| onset          = Birth or early infancy
wrap = yes
| duration        = Lifelong
width=750
| causes          = [[Genetic mutation]] in the [[STS gene]]
height=600
| risks          = Male gender (due to X-linked inheritance)
</youtube>
| diagnosis      = [[Clinical examination]], [[genetic testing]]
 
| differential    = [[Ichthyosis vulgaris]], [[Netherton syndrome]], [[Lamellar ichthyosis]]
==Summary==
| treatment      = [[Moisturizers]], [[keratolytics]]
* X-linked ichthyosis is a disorder in which the skin cells are produced at a normal rate but they do not separate properly at the surface of the stratum corneum (the outermost layer of the skin).
| frequency      = 1 in 2,000 to 6,000 males
* This slows the rate of shedding of the skin cells, resulting in a build-up of scales.
| deaths          = Rarely life-threatening
* The scales of X-linked ichthyosis are often dark and usually cover only a portion of the body.
}}
* Typically, the trunk and back of the neck are more likely to be affected.
[[File:Boy_with_X_linked_Ichthyosis_rotated.JPG|Boy with X-linked Ichthyosis|thumb|left]]
* Scales are usually not found on the face, scalp, palms of the hands, and soles of the feet. 
[[File:IchthyosisXlinked2.JPG|Ichthyosis X-linked|thumb]]
 
[[File:DHEA_sulfate.png|DHEA sulfate|thumb|left]]
[[File:Boy with X linked Ichthyosis rotated.JPG|thumb|X linked ichthyosis]]
'''X-linked ichthyosis''' is a [[genetic disorder]] characterized by dry, scaly skin. It is one of the most common forms of [[ichthyosis]], a group of skin disorders that lead to dry, thickened, and scaly skin. X-linked ichthyosis is caused by a deficiency of the enzyme steroid sulfatase, which is due to a mutation in the [[STS gene]] located on the X chromosome.
 
==Etiology==
==Genetics==
X-linked ichthyosis is caused by a deletion or mutation in the [[STS gene]] (steroid sulfatase gene) on the X chromosome. This gene is responsible for the production of the enzyme steroid sulfatase, which is involved in the metabolism of cholesterol sulfate. The deficiency of this enzyme leads to the accumulation of cholesterol sulfate in the outer layer of the skin, resulting in the characteristic scaling.
* X-linked ichthyosis is inherited in an X-linked recessive manner.
==Epidemiology==
* X-linked ichthyosis mostly affects males.  
X-linked ichthyosis affects approximately 1 in 2,000 to 6,000 males worldwide. It is an X-linked recessive condition, meaning it primarily affects males, while females are typically carriers of the genetic mutation.
 
==Clinical Features==
==Cause==
The primary symptom of X-linked ichthyosis is the presence of dry, scaly skin. The scales are often dark and adhere tightly to the skin, particularly on the trunk, neck, and extremities. The face, palms, and soles are usually spared. Other features may include:
It is usually caused by a mutation or deletion in the STS gene and is inherited in an X-linked recessive manner.  
* [[Corneal opacities]]: These are asymptomatic and do not affect vision.
 
* [[Cryptorchidism]]: Undescended testicles may occur in some affected males.
==Rare genetic syndromes==
In rare cases, the ichthyosis can be part of a genetic syndrome in which other parts of the body are affected.  
 
==Symptoms==
'''80%-99% of people have these symptoms'''
 
* Dry skin
* Hypohidrosis
* Ichthyosis
 
'''30%-79% of people have these symptoms'''
* Attention deficit hyperactivity disorder
 
'''5%-29% of people have these symptoms'''
* Cryptorchidism
* Neurological speech impairment
 
===Other symptoms===
* Abnormality of metabolism/homeostasis
* Ichthyosiform erythroderma
* [[Neoplasm]]
 
==Diagnosis==
==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.
Diagnosis of X-linked ichthyosis is primarily clinical, based on the characteristic skin findings. Genetic testing can confirm the diagnosis by identifying deletions or mutations in the [[STS gene]]. Prenatal diagnosis is possible if there is a known family history of the condition.
 
==Differential Diagnosis==
==Treatment==
X-linked ichthyosis should be differentiated from other forms of ichthyosis, such as:
Topical treatment may consist of alpha-hydroxy acids, lubricating bath oils, and emollients.
* [[Ichthyosis vulgaris]]
For adult patients, systemic retinoids may be an option, especially during winter when the ichthyosis is often more severe.
* [[Lamellar ichthyosis]]
The ichthyosis is life-long, but the scaling may improve with age.
* [[Congenital ichthyosiform erythroderma]]
 
==Management==
<youtube>
There is no cure for X-linked ichthyosis, but symptoms can be managed with:
title='''{{PAGENAME}}'''
* [[Emollients]]: These help to moisturize the skin and reduce scaling.
movie_url=http://www.youtube.com/v/VgHeXTnEh1I
* [[Keratolytics]]: Agents such as salicylic acid can help to remove scales.
&rel=1
* [[Topical retinoids]]: These may be used in severe cases to reduce scaling.
embed_source_url=http://www.youtube.com/v/VgHeXTnEh1I
==Prognosis==
&rel=1
X-linked ichthyosis is a lifelong condition, but it does not affect life expectancy. The severity of symptoms can vary, and some individuals may experience improvement with age.
wrap = yes
==Genetic Counseling==
width=750
Genetic counseling is recommended for families affected by X-linked ichthyosis. Female carriers have a 50% chance of passing the mutated gene to their sons, who will be affected, and a 50% chance of passing it to their daughters, who will be carriers.
height=600
==Research Directions==
</youtube>
Current research is focused on understanding the molecular mechanisms of X-linked ichthyosis and developing targeted therapies. Gene therapy and enzyme replacement therapy are potential future treatments.
 
==See Also==
=== Genetic counseling issues ===
Since the majority of cases appear to occur through transmission of an ''STS'' deletion from a carrier mother, enzyme testing or DNA testing should be performed in the mother of any newly diagnosed simplex case (i.e. the first case in a family). 
 
In the case of an extended family with many affected individuals, carrier status can often be assigned based on pedigree analysis.
 
* Males with XLI will transmit the X chromosome harboring the ''STS'' deletion or mutation to each of his female offspring, who will therefore be an [[X-linked recessive|obligate carrier]].  However, all male offspring will be unaffected, since they receive their father's Y chromosome.
* Female carriers of an ''STS'' deletion or mutation have a 50% chance with each pregnancy of transmitting it to an offspring.  Thus, each male offspring has a 50% chance of being affected by XLI, while each female offspring has a 50% chance of being a carrier for this condition.  Any individual that inherits the mother's normal copy of the ''STS'' gene will be unaffected and will have an extremely low chance of having a child affected with this condition.
 
Due to random segregation of the chromosomes during [[gametogenesis]], each pregnancy will be subject to the same probabilities, regardless of the number of previously affected or unaffected offspring. The above recurrence risks are based on the assumption that an affected male or carrier female will have children with an unaffected or non-carrier individual. The risks of having affected offspring would clearly increase in the case of a union between a male with XLI and a carrier female.
 
== See also ==
* [[Ichthyosis]]
* [[Ichthyosis]]
* [[Carvajal syndrome]]
* [[Genetic disorders]]
 
* [[Dermatology]]
{{Congenital malformations and deformations of integument}}
==External Links==
{{X-linked disorders}}
* [https://www.genome.gov/Genetic-Disorders/X-linked-Ichthyosis National Human Genome Research Institute]
{{Defects of steroid metabolism}}
* [https://www.dermnetnz.org/topics/x-linked-ichthyosis/ DermNet NZ]
{{stub}}
[[Category:Genetic disorders]]
{{adapted}}
[[Category:Dermatology]]
[[Category:Genodermatoses]]
[[Category:Cholesterol and steroid metabolism disorders]]
[[Category:Rare diseases]]
[[Category:Rare diseases]]

Latest revision as of 08:55, 13 April 2025

Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD's medical weight loss NYC, sleep center NYC
Philadelphia medical weight loss and Philadelphia sleep clinics

X-linked ichthyosis
File:X-linked recessive.svg
Synonyms Steroid sulfatase deficiency
Pronounce
Specialty Dermatology, Genetics
Symptoms Dry skin, scaling, corneal opacities
Complications N/A
Onset Birth or early infancy
Duration Lifelong
Types N/A
Causes Genetic mutation in the STS gene
Risks Male gender (due to X-linked inheritance)
Diagnosis Clinical examination, genetic testing
Differential diagnosis Ichthyosis vulgaris, Netherton syndrome, Lamellar ichthyosis
Prevention N/A
Treatment Moisturizers, keratolytics
Medication N/A
Prognosis N/A
Frequency 1 in 2,000 to 6,000 males
Deaths Rarely life-threatening


File:Boy with X linked Ichthyosis rotated.JPG
Boy with X-linked Ichthyosis
File:IchthyosisXlinked2.JPG
Ichthyosis X-linked
File:DHEA sulfate.png
DHEA sulfate

X-linked ichthyosis is a genetic disorder characterized by dry, scaly skin. It is one of the most common forms of ichthyosis, a group of skin disorders that lead to dry, thickened, and scaly skin. X-linked ichthyosis is caused by a deficiency of the enzyme steroid sulfatase, which is due to a mutation in the STS gene located on the X chromosome.

Etiology[edit]

X-linked ichthyosis is caused by a deletion or mutation in the STS gene (steroid sulfatase gene) on the X chromosome. This gene is responsible for the production of the enzyme steroid sulfatase, which is involved in the metabolism of cholesterol sulfate. The deficiency of this enzyme leads to the accumulation of cholesterol sulfate in the outer layer of the skin, resulting in the characteristic scaling.

Epidemiology[edit]

X-linked ichthyosis affects approximately 1 in 2,000 to 6,000 males worldwide. It is an X-linked recessive condition, meaning it primarily affects males, while females are typically carriers of the genetic mutation.

Clinical Features[edit]

The primary symptom of X-linked ichthyosis is the presence of dry, scaly skin. The scales are often dark and adhere tightly to the skin, particularly on the trunk, neck, and extremities. The face, palms, and soles are usually spared. Other features may include:

Diagnosis[edit]

Diagnosis of X-linked ichthyosis is primarily clinical, based on the characteristic skin findings. Genetic testing can confirm the diagnosis by identifying deletions or mutations in the STS gene. Prenatal diagnosis is possible if there is a known family history of the condition.

Differential Diagnosis[edit]

X-linked ichthyosis should be differentiated from other forms of ichthyosis, such as:

Management[edit]

There is no cure for X-linked ichthyosis, but symptoms can be managed with:

  • Emollients: These help to moisturize the skin and reduce scaling.
  • Keratolytics: Agents such as salicylic acid can help to remove scales.
  • Topical retinoids: These may be used in severe cases to reduce scaling.

Prognosis[edit]

X-linked ichthyosis is a lifelong condition, but it does not affect life expectancy. The severity of symptoms can vary, and some individuals may experience improvement with age.

Genetic Counseling[edit]

Genetic counseling is recommended for families affected by X-linked ichthyosis. Female carriers have a 50% chance of passing the mutated gene to their sons, who will be affected, and a 50% chance of passing it to their daughters, who will be carriers.

Research Directions[edit]

Current research is focused on understanding the molecular mechanisms of X-linked ichthyosis and developing targeted therapies. Gene therapy and enzyme replacement therapy are potential future treatments.

See Also[edit]

External Links[edit]

Retrieved from "https://wikimd.com/index.php?title=X-linked_ichthyosis&oldid=6549851"