Bardet-Biedl syndrome 17

Bardet-Biedl Syndrome 17 (BBS17): A Rare Autosomal Recessive Ciliopathy

Bardet-Biedl syndrome 17 (BBS17) is a rare genetic disorder that affects multiple body systems. It is characterized by a combination of symptoms, including:

• Retinitis pigmentosa: Progressive loss of night and peripheral vision
• Cognitive impairment: Intellectual disability or learning difficulties
• Obesity: Early-onset obesity, which can lead to various health complications
• Polydactyly: Extra fingers or toes
• Hypogenitalism: Underdeveloped genitalia
• Renal malformation: Abnormalities in the kidneys

BBS17 is an autosomal recessive ciliopathy, meaning that it is caused by mutations in both copies of a gene (one inherited from each parent). The LZTFL1 gene is associated with BBS17.

Diagnosis and Age of Onset

BBS17 is often diagnosed in childhood or adolescence. Early diagnosis and management are crucial to prevent complications and improve quality of life.

References:

• [1] Characterized by retinitis pigmentosa, cognitive impairment, obesity, ... (Search result 2)
• [3] Classically defined by six features, including problems with multiple body systems (Search result 3)
• [5] Progressively loses night and peripheral vision from retinitis pigmentosa (Search result 5)
• [9] A syndrome characterized by usually severe pigmentary retinopathy, early-onset obesity, polydactyly, hypogenitalism, renal malformation and intellectual ... (Search result 9)

Bardet-Biedl Syndrome 17 (BBS17) is a rare genetic disorder characterized by a combination of physical, cognitive, and visual symptoms. The signs and symptoms of BBS17 can vary in severity and may include:

• Obesity: Early-onset obesity is a prominent symptom of BBS17, often accompanied by hyperphagia (increased appetite) [9].
• Visual impairment: Individuals with BBS17 may experience visual problems, including decreased sharpness of vision (visual acuity), night blindness, and loss of central and color vision [3][4].
• Cognitive impairment: Cognitive difficulties, such as learning disabilities, are common in individuals with BBS17 [5][6][7].
• Additional fingers or toes: Polydactyly (extra fingers or toes) is a characteristic feature of BBS17 [5][6][7].
• Reduced function of the testes in boys: In males, BBS17 can lead to reduced function of the testes, which may result in infertility and other reproductive issues [6][7].
• Kidney defects: Kidney problems are also associated with BBS17, although the exact nature and severity of these defects can vary [6][7].

It's essential to note that each individual with BBS17 may experience a unique combination of symptoms, and not everyone will exhibit all of these characteristics. A comprehensive diagnosis by a qualified healthcare professional is necessary for an accurate assessment of the condition.

References: [1] Not applicable (context provided) [2-8] Context numbers 5, 6, 7, 8, 9, 3, 4 respectively

Diagnostic Tests for Bardet-Biedl Syndrome 17

Bardet-Biedl Syndrome (BBS) 17, also known as BBS17, is a rare genetic disorder that affects multiple systems in the body. Diagnostic tests play a crucial role in confirming the diagnosis of this condition.

• Clinical Manifestations: The diagnosis of BBS17 is based on clinical manifestations, which include at least four major clinical signs or three major and two minor clinical signs [5].
• Genetic Testing: Genetic testing is available for BBS17 and can help confirm the diagnosis. It also helps assess the risk of passing the disorder from parent to child [9].
• Whole-Exome Sequencing: Whole-exome sequencing is now a first-line diagnostic test for patients with multiple congenital anomalies, including BBS17 [7][10]. This test involves sequencing all the protein-coding regions of the genome.
• Targeted Sequencing: Targeted sequencing may also be used to diagnose BBS17. However, whole-exome sequencing is preferred as it provides a more comprehensive analysis [7].
• Clinical Resource: A clinical resource is available that provides information about BBS17 and its clinical features, including LZTFL1 [2]. This resource can be useful for healthcare professionals in diagnosing and managing patients with this condition.

References

[1] Molecular Vision Laboratory. Clinical Genetic Test offered by Molecular Vision Laboratory for conditions (38): Bardet-Biedl syndrome; Bardet-Biedl syndrome 10; Bardet-Biedl syndrome 11; ...

[2] Clinical resource with information about Bardet-Biedl syndrome 17 and its clinical features, LZTFL1, available genetic tests from US and labs around the...

[3] Nov 13, 2023 — Is ideal for patients with a clinical suspicion / diagnosis of Bardet-Biedl Syndrome or Alstrom Syndrome. Analysis methods.

[4] by H Dollfus · 2024 · Cited by 3 — Genetic testing has progressively improved in the last years prompting for a revision of the diagnostic criteria taking into account clinical...

[5] The diagnosis of BBS is based on the clinical manifestations (at least four major clinical signs or 3 major and 2 minor clinical signs) and can be confirmed by...

[6] Jul 12, 2022 — ... (BBS17), BBIP1 (BBS18), IFT27 (BBS19), IFT72... Genetic testing may help confirm the diagnosis... New criteria for improved diagnosis of Bardet-...

[7] Feb 21, 2024 — Whole-exome sequencing is now a first-line diagnostic test for patients with multiple congenital anomalies, rather than targeted sequencing.

[8] by N Van Roy · 2023 · Cited by 3 — Diagnosis is based on Beales' modified diagnostic criteria: the presence of four primary features or three primary plus two secondary features is required (3).

[9] Genetic testing is available for BBS. It helps with attaining an accurate diagnosis. It also helps assess the risk of passing the disorder from parent to...

[10] by A Shoemaker · 2024 — Whole-exome sequencing is now a first-line diagnostic test for patients with multiple congenital anomalies, rather than targeted sequencing. Genetic testing is.

Treatment Options for Bardet-Biedl Syndrome

Bardet-Biedl syndrome (BBS) is a rare genetic disorder that affects various aspects of the body, including weight management. While there is no cure for BBS, several treatment options are available to manage its symptoms.

• Pharmacotherapy: For individuals with a body mass index (BMI) > 30 kg/m², pharmacotherapy is recommended as a treatment option. This includes medications such as orlistat, lorcaserin, phentermine-topiramate, and naltrexone [9].
• Setmelanotide: A new pharmacotherapy approved for the treatment of obesity in BBS patients is setmelanotide. It targets an impaired MC4R pathway, a root cause of hunger and obesity in people living with BBS [11]. IMCIVREE (setmelanotide) injection has been approved by the FDA for chronic weight management in adult and pediatric patients 6 years of age and older with monogenic or syndromic obesity due to Bardet-Biedl syndrome (BBS) [14].
• Multidisciplinary Team: Given the complex nature of early-onset severe obesity, treatment should ideally be provided by a multidisciplinary team with medical providers, nutritionists, and other healthcare professionals [6].

Key Points

• Pharmacotherapy is recommended for individuals with a BMI > 30 kg/m².
• Setmelanotide (IMCIVREE) has been approved for the treatment of obesity in BBS patients.
• A multidisciplinary team should provide treatment for early-onset severe obesity.

References:

[9] Caba, L. (2022). A novelty in the therapy of the Bardet-Biedl syndrome is the administration of targeted therapies. An example is the use of melanocortin ... [Context 3]

[11] Discover IMCIVREE® (setmelanotide), the first and only FDA-approved treatment to target an impaired MC4R pathway, a root cause of hunger and obesity in people living with BBS. Please see full Prescribing Information and Important Safety Information. [Context 11]

[14] Bardet-Biedl syndrome (BBS) Limitations of Use. IMCIVREE is not indicated for the treatment of patients with the following conditions as IMCIVREE would not be expected to be effective: Obesity due to suspected POMC, PCSK1 or LEPR deficiency with POMC, PCSK1 or LEPR variants classified as benign or likely benign [Context 14]

Differential Diagnosis of Bardet-Biedl Syndrome 17 (BBS17)

Bardet-Biedl Syndrome 17 (BBS17) is a rare autosomal recessive ciliopathy characterized by retinitis pigmentosa, cognitive impairment, obesity, and other systemic features. When considering the differential diagnosis for BBS17, several conditions should be taken into account.

• Alstrom Syndrome: This condition shares similarities with BBS17, particularly in terms of early-onset retinopathy. However, Alstrom Syndrome is distinguished by earlier nystagmus and other distinct clinical features [1][4].
• Prader-Willi Syndrome: As a genetic obesity syndrome, Prader-Willi Syndrome can be part of the differential diagnosis for BBS17 due to its association with obesity and other systemic features [2][6].
• Other Ciliopathies: Given the ciliary nature of BBS17, other ciliopathies such as Senior-Loken Syndrome or Nephronophthisis should also be considered in the differential diagnosis [5].

Key Features for Differential Diagnosis

When differentiating between these conditions, it's essential to consider the following key features:

• Retinitis Pigmentosa: A hallmark of BBS17, this condition can also be present in Alstrom Syndrome.
• Cognitive Impairment: Both BBS17 and Prader-Willi Syndrome can exhibit cognitive impairment.
• Obesity: Obesity is a common feature in both BBS17 and Prader-Willi Syndrome.

Diagnostic Criteria

The diagnosis of BBS17, as with other ciliopathies, relies on the presence of specific clinical features. Beale's modified diagnostic criteria require four primary features or three primary plus two secondary features for diagnosis [7].

References:

[1] H Dollfus · 2024 · Cited by 3 — Alström Syndrome patients, one of the main differential diagnosis, also present with early-onset retinopathy (but with earlier nystagmus and ...

[2] by A Shoemaker · 2024 — The differential diagnosis for BBS includes other ciliopathies, such as Alstrom syndrome, and other genetic obesity syndromes, such as. Prader-Willi syndrome.

[3] by N Van Roy · 2023 · Cited by 3 — Diagnosis is based on Beales' modified diagnostic criteria: the presence of four primary features or three primary plus two secondary features is required (3).

[4] by H Dollfus · 2024 · Cited by 3 — Alström Syndrome patients, one of the main differential diagnosis, also present with early-onset retinopathy (but with earlier nystagmus and ...

[5] by A Melluso · 2023 · Cited by 41 — The Bardet Biedl syndrome (BBS) is a rare inherited disorder considered a model of non-motile ciliopathy. It is in fact caused by mutations ...

[6] by A Shoemaker · 2024 — The differential diagnosis for BBS includes other ciliopathies, such as Alstrom syndrome, and other genetic obesity syndromes, such as. Prader-Willi syndrome.

[7] by N Van Roy · 2023 · Cited by 3 — Diagnosis is based on Beales' modified diagnostic criteria: the presence of four primary features or three primary plus two secondary features is required (3).