Chylomicron retention disease: Difference between revisions

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{{Infobox medical condition (new)
{{Short description|A rare genetic disorder affecting lipid metabolism}}
| name            = Chylomicron retention disease
{{Medical resources}}
| synonyms        = Anderson disease
<ref>{{cite web |last1=RESERVED |first1=INSERM US14-- ALL RIGHTS |title=Orphanet: Chylomicron retention disease |url=https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=71 |website=www.orpha.net |accessdate=17 July 2019 |language=en}}</ref>| image          = Autosomal recessive - en.svg
| caption        = This condition is inherited in an autosomal recessive manner
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'''Chylomicron retention disease''' is a disorder of fat absorption.<ref name="pmid3792776">{{cite journal |vauthors=Roy CC, Levy E, Green PH |title=Malabsorption, hypocholesterolemia, and fat-filled enterocytes with increased intestinal apoprotein B. Chylomicron retention disease |journal=Gastroenterology |volume=92 |issue=2 |pages=390–9 |date=February 1987 |pmid=3792776 |doi= |url=|display-authors=etal}}</ref> It is associated with [[SAR1B]].<ref name="pmid12692552">{{cite journal |vauthors=Jones B, Jones EL, Bonney SA |title=Mutations in a Sar1 GTPase of COPII vesicles are associated with lipid absorption disorders |journal=Nat. Genet. |volume=34 |issue=1 |pages=29–31 |date=May 2003 |pmid=12692552 |doi=10.1038/ng1145|display-authors=etal}}</ref> Mutations in [[SAR1B]] prevent the release of chylomicrons in the [[Circulatory system|circulation]] which leads to nutritional and developmental problems.<ref name="GHR" /> It is a rare [[Dominance (genetics)#Dominant and recessive genetic diseases in humans|autosomal recessive disorder]] with around 40 cases reported worldwide. Since the disease allele is recessive, parents usually do not show symptoms.<ref name="GHR" />


Without functional chylomicrons certain fat-soluble vitamins such as [[vitamin D]] and [[vitamin E]] cannot be absorbed. Chylomicrons have a crucial role in fat absorption and transport, thus deficiency in chylomicron functioning reduces available levels of dietary fats and fat-soluble vitamins.<ref name="GHR">http://ghr.nlm.nih.gov/condition/chylomicron-retention-disease</ref>
'''Chylomicron retention disease''' (CRD), also known as '''Anderson's disease''', is a rare [[autosomal recessive disorder]] that affects the body's ability to absorb and transport dietary [[lipids]]. This condition is characterized by the improper formation and secretion of [[chylomicrons]], which are lipoprotein particles responsible for the transport of dietary [[triglycerides]], [[cholesterol]], and [[fat-soluble vitamins]] from the [[intestine]] to other parts of the body.


=== '''Cause''' ===
==Pathophysiology==
The '''SAR1B gene''' has been identified as the cause of CRD. More than 14 different mutations in about 30 patients have been described. '''This gene encodes the Sar1b protein, which is involved in the transport of chylomicrons''' (carriers of dietary lipids) from the endoplasmic reticulum to the Golgi apparatus. This '''mutation results in accumulation of pre-chylomicron transport vesicles in the cytoplasm of enterocytes.''' [[Genotyping]] has revealed that Anderson's disease and CRD are in fact the same condition.
Chylomicron retention disease is caused by mutations in the [[SAR1B gene]], which encodes a protein involved in the transport of chylomicrons from the [[endoplasmic reticulum]] to the [[Golgi apparatus]] within [[enterocytes]]. This defect leads to the accumulation of chylomicrons in the enterocytes, preventing their release into the [[lymphatic system]] and subsequently into the [[bloodstream]]. As a result, individuals with CRD have low levels of circulating chylomicrons and [[lipoproteins]], leading to [[hypocholesterolemia]] and [[hypotriglyceridemia]].


== '''Inheritance''' ==
==Clinical Features==
[[File:Autorecessive.svg|thumb|right|Autosomal recessive inheritance, a 25% chance]]
Patients with chylomicron retention disease typically present in infancy or early childhood with symptoms related to malabsorption of dietary fats and fat-soluble vitamins. Common clinical features include:
The disease follows an [[autosomal recessive]] pattern of inheritance.


 
* [[Steatorrhea]] (fatty stools)
==Signs and symptoms==
* [[Failure to thrive]]
In the months following birth, signs and symptoms will appear. Some symptoms will manifest gradually during childhood.<ref name="GHR" />
* [[Growth retardation]]
 
* [[Muscle weakness]]
*Failure to gain weight
* [[Neurological symptoms]] due to vitamin E deficiency, such as [[ataxia]] and [[peripheral neuropathy]]
*Failure to thrive
* [[Retinitis pigmentosa]]
*[[Diarrhea]]
*Foul-smelling feces, [[steatorrhea]]
*Impaired nervous system functions
*Decreased reflexes, [[hyporeflexia]]


==Diagnosis==
==Diagnosis==
* Diagnosis is often delayed because symptoms are nonspecific and [[hypocholesterolemia]] may be attributed to [[malnutrition]] secondary to chronic [[diarrhea]].
The diagnosis of chylomicron retention disease is based on clinical presentation, laboratory findings, and genetic testing. Key diagnostic features include:
* Diagnosis is based on a history of chronic diarrhea with fat malabsorption and a characteristic abnormal lipid profile: generally a 50% decrease in total [[cholesterol]], [[LDL Cholesterol|LDL-cholesterol]] (LDL-C) and [[High-density lipoprotein (HDL-cholesterol)|high-density lipoprotein]]-cholesterol (HDL-C) in the presence of normal [[triglycerides]].
* Upper [[endoscopy]] and histology reveal fat-laden [[enterocytes]]. Elevated [[creatine kinase]] (CK) in patients with [[hypocholesterolemia]] may be suggestive of CRD.
* [[Genotyping]] makes it possible to identify the '''SAR1B gene''' mutations. Parental lipid screening may clarify the diagnosis. An absence of hypocholesterolemia in both parents favors CRD. Consanguinity is frequent in patients with the disorder.
 
'''Differential diagnosis'''
Differential diagnosis includes abetalipoproteinemia and other genetic hypocholesterolemias characterized by decreased LDL-C, such as homozygous hypobetalipoproteinemia (HBL), and acquired disorders associated with low HDL-C.
 
==Treatment==
* Follow-up should be directed toward monitoring nutrition and growth, and treatment compliance. Management should focus on prevention and early detection of complications (hepatic, neuromuscular, retinal and bone). Control of [[vitamin E]] deficiency plays a key role in preventing neurological complications. Treatment includes fat-soluble vitamin supplements and large amounts of vitamin E.
* [[Vitamin A]], in combination with vitamin E, may help to prevent ophthalmologic complications. Early vitamin D treatment makes it possible to prevent osteopenia. Vomiting, diarrhea and abdominal distension improve on a low-long chain fat diet. Dietary counseling is needed not only to monitor fat intake and improve symptoms, but also to maintain sufficient caloric and EFA intake.
 
== '''Prognosis''' ==
Very long-term follow-up into adulthood is poorly documented.


* Low levels of [[plasma triglycerides]] and [[cholesterol]]
* Low levels of fat-soluble vitamins, particularly [[vitamin E]]
* Genetic testing revealing mutations in the SAR1B gene


==References==
==Management==
{{reflist}}
Management of chylomicron retention disease focuses on dietary modifications and supplementation to address the malabsorption of fats and fat-soluble vitamins. Treatment strategies include:


{{Medical resources
* A low-fat diet to reduce the burden on the impaired lipid transport system
|  DiseasesDB      = 33188 
* Supplementation with fat-soluble vitamins, especially vitamin E, to prevent neurological complications
|  ICD10          = E78.6
* Monitoring of growth and development in children
|  ICD9            = 
|  ICDO            = 
|  OMIM            = 246700 
|  MedlinePlus    = 
|  eMedicineSubj  = 
|  eMedicineTopic  = 
|  MeshID          = C535460
|  Orphanet        = 71
}}
{{Lipidemias}}
{{Deficiencies of intracellular signaling peptides and proteins}}


[[Category:Lipid metabolism disorders]]
==Prognosis==
With appropriate dietary management and vitamin supplementation, individuals with chylomicron retention disease can lead relatively normal lives. However, early diagnosis and intervention are crucial to prevent irreversible complications, particularly those affecting the nervous system.


==Related pages==
* [[Lipid metabolism disorders]]
* [[Hypocholesterolemia]]
* [[Fat malabsorption]]
* [[Autosomal recessive disorders]]


{{genetic-disorder-stub}}
[[Category:Genetic disorders]]
[[Category:Metabolic disorders]]
[[Category:Rare diseases]]

Revision as of 19:14, 22 March 2025

A rare genetic disorder affecting lipid metabolism



Chylomicron retention disease (CRD), also known as Anderson's disease, is a rare autosomal recessive disorder that affects the body's ability to absorb and transport dietary lipids. This condition is characterized by the improper formation and secretion of chylomicrons, which are lipoprotein particles responsible for the transport of dietary triglycerides, cholesterol, and fat-soluble vitamins from the intestine to other parts of the body.

Pathophysiology

Chylomicron retention disease is caused by mutations in the SAR1B gene, which encodes a protein involved in the transport of chylomicrons from the endoplasmic reticulum to the Golgi apparatus within enterocytes. This defect leads to the accumulation of chylomicrons in the enterocytes, preventing their release into the lymphatic system and subsequently into the bloodstream. As a result, individuals with CRD have low levels of circulating chylomicrons and lipoproteins, leading to hypocholesterolemia and hypotriglyceridemia.

Clinical Features

Patients with chylomicron retention disease typically present in infancy or early childhood with symptoms related to malabsorption of dietary fats and fat-soluble vitamins. Common clinical features include:

Diagnosis

The diagnosis of chylomicron retention disease is based on clinical presentation, laboratory findings, and genetic testing. Key diagnostic features include:

Management

Management of chylomicron retention disease focuses on dietary modifications and supplementation to address the malabsorption of fats and fat-soluble vitamins. Treatment strategies include:

  • A low-fat diet to reduce the burden on the impaired lipid transport system
  • Supplementation with fat-soluble vitamins, especially vitamin E, to prevent neurological complications
  • Monitoring of growth and development in children

Prognosis

With appropriate dietary management and vitamin supplementation, individuals with chylomicron retention disease can lead relatively normal lives. However, early diagnosis and intervention are crucial to prevent irreversible complications, particularly those affecting the nervous system.

Related pages