Smith–Lemli–Opitz syndrome: Difference between revisions
From WikiMD's Wellness Encyclopedia
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[[File:Smith-Lemli-Opitz_Syndrome_1.jpg| | {{SI}} | ||
{{Infobox medical condition | |||
| name = Smith–Lemli–Opitz syndrome | |||
| image = [[File:Smith-Lemli-Opitz_Syndrome_1.jpg|250px]] | |||
| caption = Child with Smith–Lemli–Opitz syndrome | |||
| synonyms = SLOS, 7-dehydrocholesterol reductase deficiency | |||
| pronounce = | |||
| specialty = [[Medical genetics]] | |||
| symptoms = [[Intellectual disability]], [[behavioral problems]], [[microcephaly]], [[distinctive facial features]], [[syndactyly]] | |||
| onset = [[Prenatal]] | |||
| duration = Lifelong | |||
| causes = [[Genetic mutation]] in the [[DHCR7]] gene | |||
| risks = | |||
| diagnosis = [[Genetic testing]], [[clinical evaluation]] | |||
| differential = [[Trisomy 18]], [[Trisomy 13]], [[Noonan syndrome]] | |||
| prevention = | |||
| treatment = [[Cholesterol supplementation]], [[dietary management]] | |||
| medication = | |||
| prognosis = Variable, depends on severity | |||
| frequency = 1 in 20,000 to 1 in 60,000 newborns | |||
| deaths = | |||
}} | |||
'''Smith–Lemli–Opitz syndrome''' ('''SLOS''') is a rare [[autosomal recessive]] [[genetic disorder]] characterized by multiple congenital anomalies and intellectual disability. It is caused by mutations in the [[DHCR7]] gene, which encodes the enzyme 7-dehydrocholesterol reductase. This enzyme is crucial for the final step in the [[cholesterol]] biosynthesis pathway. | |||
== Signs and Symptoms == | == Signs and Symptoms == | ||
Individuals with Smith–Lemli–Opitz syndrome exhibit a wide range of symptoms, which can vary in severity. Common features include: | Individuals with Smith–Lemli–Opitz syndrome exhibit a wide range of symptoms, which can vary in severity. Common features include: | ||
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* [[Feeding difficulties]] and [[failure to thrive]] | * [[Feeding difficulties]] and [[failure to thrive]] | ||
* Behavioral problems, including [[autism spectrum disorder]]-like behaviors | * Behavioral problems, including [[autism spectrum disorder]]-like behaviors | ||
== Genetics == | == Genetics == | ||
Smith–Lemli–Opitz syndrome is inherited in an [[autosomal recessive]] manner. This means that an affected individual must inherit two copies of the mutated [[DHCR7]] gene, one from each parent. Carriers of a single mutated gene typically do not show symptoms of the disorder. | Smith–Lemli–Opitz syndrome is inherited in an [[autosomal recessive]] manner. This means that an affected individual must inherit two copies of the mutated [[DHCR7]] gene, one from each parent. Carriers of a single mutated gene typically do not show symptoms of the disorder. | ||
== Pathophysiology == | == Pathophysiology == | ||
The [[DHCR7]] gene mutation leads to a deficiency in the enzyme 7-dehydrocholesterol reductase, which is responsible for converting 7-dehydrocholesterol to cholesterol. As a result, individuals with SLOS have low levels of cholesterol and elevated levels of 7-dehydrocholesterol. Cholesterol is essential for normal embryonic development, cell membrane structure, and the synthesis of steroid hormones and bile acids. | The [[DHCR7]] gene mutation leads to a deficiency in the enzyme 7-dehydrocholesterol reductase, which is responsible for converting 7-dehydrocholesterol to cholesterol. As a result, individuals with SLOS have low levels of cholesterol and elevated levels of 7-dehydrocholesterol. Cholesterol is essential for normal embryonic development, cell membrane structure, and the synthesis of steroid hormones and bile acids. | ||
== Diagnosis == | == Diagnosis == | ||
Diagnosis of Smith–Lemli–Opitz syndrome is based on clinical features and confirmed by biochemical testing showing elevated levels of 7-dehydrocholesterol in the blood. Genetic testing can identify mutations in the [[DHCR7]] gene. | Diagnosis of Smith–Lemli–Opitz syndrome is based on clinical features and confirmed by biochemical testing showing elevated levels of 7-dehydrocholesterol in the blood. Genetic testing can identify mutations in the [[DHCR7]] gene. | ||
== Treatment == | == Treatment == | ||
There is no cure for Smith–Lemli–Opitz syndrome, and treatment is symptomatic and supportive. Management may include: | There is no cure for Smith–Lemli–Opitz syndrome, and treatment is symptomatic and supportive. Management may include: | ||
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* Surgical interventions for congenital anomalies such as cleft palate or genital abnormalities | * Surgical interventions for congenital anomalies such as cleft palate or genital abnormalities | ||
* Behavioral therapy and educational support for intellectual disability and behavioral issues | * Behavioral therapy and educational support for intellectual disability and behavioral issues | ||
== Prognosis == | == Prognosis == | ||
The prognosis for individuals with Smith–Lemli–Opitz syndrome varies depending on the severity of the condition. Early intervention and supportive care can improve the quality of life for affected individuals. | The prognosis for individuals with Smith–Lemli–Opitz syndrome varies depending on the severity of the condition. Early intervention and supportive care can improve the quality of life for affected individuals. | ||
== See also == | |||
== | |||
* [[Autosomal recessive disorder]] | * [[Autosomal recessive disorder]] | ||
* [[Genetic disorder]] | * [[Genetic disorder]] | ||
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* [[Congenital anomaly]] | * [[Congenital anomaly]] | ||
[[Category:Genetic disorders]] | [[Category:Genetic disorders]] | ||
[[Category:Autosomal recessive disorders]] | [[Category:Autosomal recessive disorders]] | ||
[[Category:Congenital disorders]] | [[Category:Congenital disorders]] | ||
[[Category:Rare diseases]] | [[Category:Rare diseases]] | ||
{{Genetic-disorder-stub}} | {{Genetic-disorder-stub}} | ||
{{medicine-stub}} | {{medicine-stub}} | ||
Latest revision as of 18:08, 8 April 2025
Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD medical weight loss NYC and sleep center NYC
| Smith–Lemli–Opitz syndrome | |
|---|---|
| |
| Synonyms | SLOS, 7-dehydrocholesterol reductase deficiency |
| Pronounce | |
| Specialty | Medical genetics |
| Symptoms | Intellectual disability, behavioral problems, microcephaly, distinctive facial features, syndactyly |
| Complications | N/A |
| Onset | Prenatal |
| Duration | Lifelong |
| Types | N/A |
| Causes | Genetic mutation in the DHCR7 gene |
| Risks | |
| Diagnosis | Genetic testing, clinical evaluation |
| Differential diagnosis | Trisomy 18, Trisomy 13, Noonan syndrome |
| Prevention | |
| Treatment | Cholesterol supplementation, dietary management |
| Medication | |
| Prognosis | Variable, depends on severity |
| Frequency | 1 in 20,000 to 1 in 60,000 newborns |
| Deaths | |
Smith–Lemli–Opitz syndrome (SLOS) is a rare autosomal recessive genetic disorder characterized by multiple congenital anomalies and intellectual disability. It is caused by mutations in the DHCR7 gene, which encodes the enzyme 7-dehydrocholesterol reductase. This enzyme is crucial for the final step in the cholesterol biosynthesis pathway.
Signs and Symptoms[edit]
Individuals with Smith–Lemli–Opitz syndrome exhibit a wide range of symptoms, which can vary in severity. Common features include:
- Intellectual disability and developmental delays
- Distinctive facial features such as microcephaly, broad nasal bridge, and upturned nostrils
- Hypotonia (low muscle tone)
- Syndactyly (webbing) of the second and third toes
- Polydactyly (extra fingers or toes)
- Cleft palate
- Genital abnormalities in males, such as hypospadias or cryptorchidism
- Feeding difficulties and failure to thrive
- Behavioral problems, including autism spectrum disorder-like behaviors
Genetics[edit]
Smith–Lemli–Opitz syndrome is inherited in an autosomal recessive manner. This means that an affected individual must inherit two copies of the mutated DHCR7 gene, one from each parent. Carriers of a single mutated gene typically do not show symptoms of the disorder.
Pathophysiology[edit]
The DHCR7 gene mutation leads to a deficiency in the enzyme 7-dehydrocholesterol reductase, which is responsible for converting 7-dehydrocholesterol to cholesterol. As a result, individuals with SLOS have low levels of cholesterol and elevated levels of 7-dehydrocholesterol. Cholesterol is essential for normal embryonic development, cell membrane structure, and the synthesis of steroid hormones and bile acids.
Diagnosis[edit]
Diagnosis of Smith–Lemli–Opitz syndrome is based on clinical features and confirmed by biochemical testing showing elevated levels of 7-dehydrocholesterol in the blood. Genetic testing can identify mutations in the DHCR7 gene.
Treatment[edit]
There is no cure for Smith–Lemli–Opitz syndrome, and treatment is symptomatic and supportive. Management may include:
- Dietary supplementation with cholesterol
- Physical therapy and occupational therapy to address developmental delays and hypotonia
- Surgical interventions for congenital anomalies such as cleft palate or genital abnormalities
- Behavioral therapy and educational support for intellectual disability and behavioral issues
Prognosis[edit]
The prognosis for individuals with Smith–Lemli–Opitz syndrome varies depending on the severity of the condition. Early intervention and supportive care can improve the quality of life for affected individuals.
See also[edit]
- Autosomal recessive disorder
- Genetic disorder
- Cholesterol
- Developmental delay
- Intellectual disability
- Congenital anomaly
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