Laurence-Moon-Biedl-Bardet syndrome

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Classification according to ICD-10
Q87.8 Other specified congenital malformation syndromes, not elsewhere classified
ICD-10 online (WHO version 2019)

The Bardet-Biedl syndrome ( LMBBS ), and Laurence-Moon-Biedl syndrome is a rare, congenital and incurable developmental disorder on the basis of autosomal - recessive inherited gene mutation in twelve possible genes. Two types of syndrome were previously distinguished: Laurence-Moon syndrome and Biedl-Bardet syndrome . Internationally, it is now divided into types 1 to 12, depending on which gene is affected. The syndrome associated with hormonal disorders , in particular gonadotropins , belongs to the group of ciliopathies .

Frequency of occurrence and origin

LMBB syndrome is rare. The probability of occurrence of the Biedl-Bardet type is between 1: 160,000 and 1: 15,000, the Laurence-Moon type is even rarer.

The basis of the disability is a gene mutation . The relevant gene locations for Bardet Biedl type are 16q21 and 11q13 .

In about 30% of BBS patients, the cause of the disease of the cilia is a disruption of the protein supply. The proteins BBS1 to BBS19 actually form the transporter BBSome , which supplies cilia with new protein building blocks . Once the BBSome has picked up cargo inside the cell, a guide brings it to the cell surface, to the cilia.
The pilot, the ARL6 molecule , docks on the BBSome protein BBS1 and guides it to the cell surface. The mechanism is universal - both in humans and in green algae. In ciliopathy, there is a genetic defect at the BBS1 binding site of ARL6 with BBS1.
BBSome therefore cannot find a pilot, so that cilia are missing important building blocks and they lose their function.

For the remaining 70% of the diseases, the cause is suspected to be an enzymopathy , a disorder of the hypothalamo-pituitary function or a kinesin defect . About 50% of children with the syndrome come from incestuous relationships.

Heterozygous carriers of the mutation are healthy and do not have an increased risk of developing typical manifestations of the syndrome such as obesity, diabetes, high blood pressure or kidney disease.

history

The syndrome was first described from a scientific point of view at different times by John Laurence (1866, specializing in ophthalmology ), his colleague Robert Charles Moon (specializing in ophthalmology), Georges Bardet (early 20th century, specializing in general medicine ) and Artur Biedl (early 20th century , Department of Endocrinology ). In 1925, the research into the symptoms was completed for the time being and the disability was named Laurence-Moon-Bardet-Biedl syndrome, which was later shortened to Bardet-Biedl syndrome.

Characteristics and symptoms

In terms of clinical symptoms, a distinction is made between Laurence-Moon syndrome (without polydactyly, i.e. without additional fingers and toes, and obesity, but with paraplegia and muscle hypotonia) and Bardet-Biedl syndrome (with polydactyly, obesity and peculiarities of the Kidneys such as kidney dysplasia ). Not all people with this peculiarity show all characteristics and not all characteristics can be demonstrated to the same extent; strong intra-family expressiveness must be observed in the diagnosis . The following characteristics can often be found in people with this gene mutation:

Treatment and differential diagnosis

The cause of the syndrome cannot be cured, only the symptoms can be treated.

Alström syndrome , Börjeson-Forssman-Lehmann syndrome , McKusick-Kaufman syndrome , MORM syndrome , Prader-Willi syndrome , Smith-Lemli-Opitz syndrome , Pallister-Hall syndrome come as a differential diagnosis . Syndrome , Cohen syndrome and the clinically similar Biemond syndrome II in question. The clinical picture is also similar to Fröhlich's syndrome .

See also

literature

  • Gerhard Neuhäuser: Syndromes in people with intellectual disabilities. Causes, manifestations and consequences . 3. Edition. Lebenshilfe-Verlag, Marburg 2010, ISBN 978-3-88617-315-0
  • Regine Witkowski u. a .: Lexicon of syndromes and malformations. Causes, Genetics, and Risks . Springer, Berlin 2003, ISBN 3-540-44305-3

Web links

Individual evidence

  1. ^ A. Mourão, AR Nager, MV Nachur, E. Lorentzen: Structural basis for membrane targeting of the BBSome by ARL6. . In: NSMB . November 17, 2014. doi : 10.1038 / nsmb.2920 .
  2. ↑ Michael P Webb, et al .: Autosomal recessive Bardet-Biedl syndrome: first-degree relatives have no predisposition to metabolic and renal disorders . In: Kidney International . 76, No. 2, July 2009, ISSN  1523-1755 , pp. 215-223. doi : 10.1038 / ki.2009.116 . PMID 19367329 .