He Bardet's syndrome Biedl Is a rare disease of genetic origin characterized mainly by the development of people born with six fingers.
It is also linked to weight, since it develops a type of obesity quite rare and infrequent. To learn more about this disorder, its symptoms, causes and treatment, continue reading.
Characteristics of Bardet's syndrome Biedl
Bardet Biedl syndrome (BBS), also called Laurence-Moon-Bardet-Biedl syndrome (LMBBS), is a genetic disorder with multisystemic involvement, ie it affects multiple systems of the body, thereby worsening The victims are even greater.
The disease was first described in 1866 by British ophthalmologists, JC Laurence and RC Luna, who described four siblings with retinitis pigmentosa, overweight, hypogonadism, and other symptoms that will be discussed later.
This syndrome belongs to a group of rare diseases known as Ciliopathies . They are caused by a hereditary anomaly in the cilia (thin microscopic structures, like hair) that causes serious problems of vision.
Symptom
Since this syndrome affects different parts of the body, its symptoms will therefore be very variable, even within the same family that has it.
Among the most outstanding symptoms we have:
- Retinitis pigmentosa : Renitis is due to a dystrophy in the cones and canes, being one of the major characteristics of this syndrome, since it gives rise to serious problems in the vision. Particularly highlights the progressive deterioration of the retina.
Symptoms include excessive sensitivity to bright light, reduced vision, and loss of vision. Symptomatology develops during infancy and childhood, ending with blindness in more than 90% of cases, in adolescence or adulthood.
- Polycystic Kidneys : About 50% of people with abnormalities in the kidneys are affected in some way, while 5% develop kidney failure. These problems are so serious that if left untreated they can even cause death.
- Postaxial polydactyly : Includes an extra finger next to the fifth finger in feet or hands, occurring in 62% of cases. The fingers are shorter and the bones of the hands and feet are wider.
- Obesity : Is another characteristic feature of the Bardet Biedl syndrome. It usually begins in early childhood and continues into adulthood.
Complications include type 2 diabetes, high blood pressure (hypertension), and very high cholesterol levels (hypercholesterolemia).
- Lack of development of the genitals and Infertility : Mainly in men, because of a failure in the production of hormones, also called Hypogonadism .
- Learning Disorders : Difficulties in speech and language.
- Behavioral problems : They often have inappropriate outbursts with what this would be a symptom of emotional immaturity.
- Different facial features : Include dental anomalies and partial and even complete loss of sense of smell ( anosmia ).
- Neurological problems : That can cause as much difficulties in the coordination as in the balance.
- It is also associated with serious manifestations such as congenital heart disease and Hirschsprung disease , Which is a bowel disease. Given the severity of the symptomatology, it is very important that patients have routine check-ups with doctors and specialists.
The majority of this symptomatology occurs many years after the onset of the disease, so the diagnosis is quite complicated to perform. In this way, the diagnosis is usually made after 9 years, which means that it is a rather late stage.
Epidemiology
Bardet Biedl syndrome is one of the rarest diseases in the world. It has a prevalence of 1 in 140,000-160,000 newborns in most of North America and Europe.
As a curiosity, on the island of Newfoundland (east coast of Canada) affects 1 of 17,000 newborns. It also occurs most frequently in the Bedouin population of Kuwait, which affects approximately 1 in 13,500 births.
Causes
Bardet's syndrome Biedl is a genetic disorder inherited from a Autosomal recessive pattern . This means that both copies of a gene in each BBS cell have mutations.
It has been confirmed that there are 14 genes that are related to this syndrome. These are called BBS.
The most common mutation occurs in the BBS1 gene that is present in approximately 18% -32% of those affected.
These problems in the genes are the result of the lack or malfunction of different proteins, which are involved in the functioning of the cilia.
Cilia are microscopic projections that protrude from many cell types. These are involved in cell movement and chemical signaling.
Cilia are also needed to be able to perceive sensory stimuli such as sight, smell and hearing.
In general, the parents of an individual with Bardet Biedl syndrome each carry a copy of the mutated gene, but these do not show signs or symptoms of the disease, they are only carriers.
In some cases of Bardet Biedl syndrome, it appears that at least three mutations (trialelic inheritance) are required to show the symptoms of the disease.
But in addition to inheriting a mutation of the same gene from each parent, you also need to have at least one more mutation from another gene located on a different chromosome to have the syndrome.
Diagnosis
To carry out the diagnosis it is considered that a person has 4 characteristics of the so-called"primary"or 3 of the primary findings and two of the"secondary findings"of the syndrome.
Among the primary found:
-Retinitis pigmentosa
Polydactyly
-Obesity
-Anomalies in kidneys
-Hipogonadism
-Difulties of learning
Among the secondary anomalies would be:
-Resist in the language
-Developmental delay
-Problems of behavior
- Difficulties of coordination and balance
-Dental anomaly
Cardiac changes
-Little smell
-Type 2 diabetes
-Hirschsprung's disease
-Facial anomalies
Among the techniques used for its diagnosis is prenatal ultrasound, which is performed in the second trimester of pregnancy. It can detect some anomalies such as polydactyly or polycystic kidneys.
Molecular genetics techniques would also detect the syndrome, such as through an analysis of DNA .
On the other hand is the Electroretinography (ERG), a clinical trial to evaluate the functioning of the retina.
Treatment
So far there is no cure or form to stop the Bardet Biedl syndrome. In general, the manifestations of the disease are treated according to the symptomatology, such as vision problems, obesity, kidney problems, etc. And according to the needs of each individual.
It is important that ophthalmologic and renal function evaluations are performed routinely, as failure to treat kidney failure can lead to death.
On the other hand, since there is no specific treatment for progressive loss of vision, its early evaluation will help to plan a better treatment in the face of the high possibility of blindness that has this disorder.
With regard to hypogonadism, hormone treatments are often used. The polydactyly can be corrected by surgery.
It is necessary to emphasize that the sooner an early detection is carried out, the better its prognosis and evolution will be.
To control obesity, it is recommended to include a Healthy and balanced diet , in addition to To do physical exercise On a regular basis, to avoid other complications. It is important to start treatment at an early age for a better life quality Of the patient.
There are also medications such as lipase inhibitors that can help decrease appetite. Special caution must be taken with this type of treatment, as only your doctor can prescribe it as long as you are not going to have problems with them.
It should be noted that the majority of patients who have Bardet's syndrome have dysfunctions in the kidneys and liver.
Through early intervention and special education will work all those Cognitive aspects .
It is also recommended to carry out an assessment of the individual needs in the educational aspects, since the majority of adults with this syndrome can lead perfectly independent living.
As for kidney problems, a transplant is usually done. The problem is that many of the immunosuppressive drugs that have to be used after the operation can lead to even more problems.
Finally we can not forget the essential and valuable that is both psychological support and social support with other children and families who also suffer from Bardet Beidl syndrome.
I hope you liked it, if you have any questions, leave a comment, Thanks!
Hereafter I leave you the necessary resources in case you are not interested
The Spanish Federation of Rare Diseases (ERDF)
C / Pamplona 32 - ZIP: 28039 Madrid
Spain
Phone: 915334008
Email: [Email protected]
Link in the network: http://www.enfermedades-raras.org
Spanish Association for the Registration and Study of Congenital Malformations (ASEREMAC)
Address: C / Faculty of Medicine. Complutense University
Location: 28040 Madrid
Province: Madrid
Phones: 913941587, 913941591
FAX: 913941592
1000 Foundation for the Investigation of Congenital Defects
Address: C / Serrano, 140
Location: 28006 Madrid
Province: Madrid
Phones: 913941587
FAX: 913941592
WEB: http://www.fundacion1000.es/
Spanish Federation of Associations of Rare Diseases (ERDF)
Address: c / Enrique Marco Dorta, 6 local
Location: 41018 Sevilla
Telephone: 902 18 17 25
FAX: 954 98 98 93
E-mail: [Email protected]
European Organization for Rare Disorders (EURORDIS)
Address: Plateforme Maladies Rares 102, Rue Didot
Location: 75014 Paris
Phone: 0033156535340
FAX: 0033156535215
E-mail: [Email protected]
WEB: http://www.eurordis.org
National Association of Bardet Biedl Syndrome and Cilopathies (AnaSbabi)
Enlance in the network: www.anasbabiciliopatias.org
References
- New criteria for improved diagnosis of Bardet-Biedl syndrome: results of a population survey P L Beales, N Elcioglu, A S Woolf, D Parker, F A Flinter.