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Advances in Experimental Medicine and... 2018Alström syndrome is an autosomal recessive disease with multisystem involvement, including cone-rod dystrophy, hearing loss, type 2 diabetes, insulin resistance with... (Review)
Review
Alström syndrome is an autosomal recessive disease with multisystem involvement, including cone-rod dystrophy, hearing loss, type 2 diabetes, insulin resistance with hyperinsulinemia, dilated cardiomyopathy, and progressive hepatic and renal failure. Patients present in childhood with photophobia and nystagmus, and mimic Leber congenital amaurosis (LCA). The fundus shows pigmentary retinopathy with peau d'orange appearance and some fine white dots like drusen around the macula; the disc is pale, with attenuated retinal vessels (Fig. 35.1). Patients have short stature; boys have hypogonadotropic hypogonadism and girls have polycystic ovary syndrome (PCOS). Obesity is always present, with markedly increased triglyceride and VLDL-C levels; arterial hypertension is diagnosed as early as 2 years of age. There is no polydactyly or syndactyly. About half have developmental delay, but intelligence is usually normal.
Topics: Alstrom Syndrome; Child; Child, Preschool; Diabetes Mellitus, Type 2; Female; Humans; Male; Obesity; Polycystic Ovary Syndrome; Retina; Retinitis Pigmentosa
PubMed: 30578508
DOI: 10.1007/978-3-319-95046-4_35 -
The Lancet. Diabetes & Endocrinology Dec 2022Impaired cilial signalling in the melanocortin-4 receptor (MC4R) pathway might contribute to obesity in patients with Bardet-Biedl syndrome and Alström syndrome, rare... (Randomized Controlled Trial)
Randomized Controlled Trial
Efficacy and safety of setmelanotide, a melanocortin-4 receptor agonist, in patients with Bardet-Biedl syndrome and Alström syndrome: a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial with an open-label period.
BACKGROUND
Impaired cilial signalling in the melanocortin-4 receptor (MC4R) pathway might contribute to obesity in patients with Bardet-Biedl syndrome and Alström syndrome, rare genetic diseases associated with hyperphagia and early-onset severe obesity. We aimed to evaluate the effect of setmelanotide on bodyweight in these patients.
METHODS
This multicentre, randomised, 14-week double-blind, placebo-controlled, phase 3 trial followed by a 52-week open-label period, was performed at 12 sites (hospitals, clinics, and universities) in the USA, Canada, the UK, France, and Spain. Patients aged 6 years or older were included if they had a clinical diagnosis of Bardet-Biedl syndrome or Alström syndrome and obesity (defined as BMI >97th percentile for age and sex for those aged 6-15 years and ≥30 kg/m for those aged ≥16 years). Patients were randomly assigned (1:1) using a numerical randomisation code to receive up to 3·0 mg of subcutaneous setmelanotide or placebo once per day during the 14-week double-blind period, followed by open-label setmelanotide for 52 weeks. The primary endpoint, measured in the full analysis set, was the proportion of patients aged 12 years or older who reached at least a 10% reduction in bodyweight from baseline after 52 weeks of setmelanotide treatment. This study is registered with ClinicalTrials.gov, NCT03746522.
FINDINGS
Between Dec 10, 2018, and Nov 25, 2019, 38 patients were enrolled and randomly assigned to receive setmelanotide (n=19) or placebo (n=19; 16 with Bardet-Biedl syndrome and three with Alström syndrome in each group). In terms of the primary endpoint, 32·3% (95% CI 16·7 to 51·4; p=0·0006) of patients aged 12 years or older with Bardet-Biedl syndrome reached at least a 10% reduction in bodyweight after 52 weeks of setmelanotide. The most commonly reported treatment-emergent adverse events were skin hyperpigmentation (23 [61%] of 38) and injection site erythema (18 [48%]). Two patients had four serious adverse events (blindness, anaphylactic reaction, and suicidal ideation); none were considered related to setmelanotide treatment.
INTERPRETATION
Setmelanotide resulted in significant bodyweight reductions in patients with Bardet-Biedl syndrome; however, these results were inconclusive in patients with Alström syndrome. These results support the use of setmelanotide and provided the necessary evidence for approval of this drug as the first treatment for obesity in patients with Bardet-Biedl syndrome.
FUNDING
Rhythm Pharmaceuticals.
Topics: Humans; Receptor, Melanocortin, Type 4; Alstrom Syndrome; Bardet-Biedl Syndrome; Treatment Outcome; Obesity
PubMed: 36356613
DOI: 10.1016/S2213-8587(22)00277-7 -
Intractable & Rare Diseases Research Nov 2021Alström syndrome is a rare monogenic ciliopathy caused by a mutation to the () gene. Alström syndrome has an autosomal recessive nature of inheritance. Approximately... (Review)
Review
Alström syndrome is a rare monogenic ciliopathy caused by a mutation to the () gene. Alström syndrome has an autosomal recessive nature of inheritance. Approximately 1,200 cases of Alström syndrome have been identified worldwide. Complications of the disease are likely caused by dysfunctional cilia with complications arising early in life. The known complications of Alström syndrome have been reported to impact multiple major organ systems, including the endocrine system, cardiac system, renal system, sensory system, and hepatic system. The symptoms of Alström syndrome have great variability in presentation and intensity but often lead to organ damage. This has resulted in a shortened lifespan for individuals affected by Alström syndrome. Individuals with the disease rare exceed the age of 50. Currently, there are no specific treatments for Alström syndrome that can cure the disease, prevent the complications, or reverse the complications. Current management involves management of symptoms with the goal of improving quality of life and lifespan. This review aims to summarize the current knowledge on the epidemiology, diagnosis, pathophysiology, complications, management, and prognosis of Alström syndrome. In addition to that, this review also aims to raise awareness and encourage research on Alström syndrome as the condition has a huge impact on affected individuals.
PubMed: 34877237
DOI: 10.5582/irdr.2021.01113 -
The Application of Clinical Genetics 2015Alström syndrome (ALMS) is a rare genetic disorder that has been included in the ciliopathies group, in the last few years. Ciliopathies are a growing group of diseases... (Review)
Review
Alström syndrome (ALMS) is a rare genetic disorder that has been included in the ciliopathies group, in the last few years. Ciliopathies are a growing group of diseases associated with defects in ciliary structure and function. The development of more powerful genetic approaches has been replaced the strategies to follow for getting a successful molecular diagnosis for these patients, especially for those without the typical ALMS phenotype. In an effort to deepen the understanding of the pathogenesis of ALMS disease, much work has been done, in order to establish the biological implication of ALMS1 protein, which is still being elucidated. In addition to its role in ciliary function and structure maintenance, this protein has been implicated in intracellular trafficking, regulation of cilia signaling pathways, and cellular differentiation, among others. All these progresses will lead to identifying therapeutic targets, thus opening the way to future personalized therapies for human ciliopathies.
PubMed: 26229500
DOI: 10.2147/TACG.S56612 -
European Journal of Human Genetics :... Dec 2007Alström Syndrome is an autosomal recessive, single gene disorder caused by mutations in ALMS1 (Chr 2p13), a novel gene of currently unknown molecular function. Alström...
Alström Syndrome is an autosomal recessive, single gene disorder caused by mutations in ALMS1 (Chr 2p13), a novel gene of currently unknown molecular function. Alström Syndrome is multisystemic, with cone-rod retinal dystrophy leading to juvenile blindness, sensorineural hearing loss, obesity, insulin resistance with hyperinsulinemia, and type 2 diabetes mellitus. Very high incidences of additional disease phenotypes that may severely affect prognosis and survival include endocrine abnormalities, dilated cardiomyopathy, pulmonary fibrosis and restrictive lung disease, and progressive hepatic and renal failure. Other clinical features in some patients are hypertension, hypothyroidism, hyperlipidemia, hypogonadism, urological abnormalities, adult short stature, and bone-skeletal disturbances. Most patients demonstrate normal intelligence, although some reports indicate delayed psychomotor and intellectual development. The life span of patients with Alström Syndrome rarely exceeds 40 years. There is no specific therapy for Alström Syndrome, but early diagnosis and intervention can moderate the progression of the disease phenotypes and improve the longevity and quality of life for patients.
Topics: Abnormalities, Multiple; Diagnosis, Differential; Follow-Up Studies; Genetic Counseling; Humans; Mutation; Syndrome
PubMed: 17940554
DOI: 10.1038/sj.ejhg.5201933 -
Endocrine Mar 2021Alström syndrome (ALMS) is a monogenic ultra-rare disorder with a prevalence of one per million inhabitants caused by pathogenic variants of ALMS1 gene. ALMS1 is... (Review)
Review
BACKGROUND
Alström syndrome (ALMS) is a monogenic ultra-rare disorder with a prevalence of one per million inhabitants caused by pathogenic variants of ALMS1 gene. ALMS1 is located on chromosome 2p13, spans 23 exons and encodes a predicted 461.2-kDa protein of 4169 amino acids. The infantile cone-rod dystrophy with nystagmus and severe visual impairment is the earliest and most consistent clinical manifestation of ALMS. In addition, infantile transient cardiomyopathy, early childhood obesity with hyperphagia, deafness, insulin resistance (IR), type 2 diabetes mellitus (T2DM), systemic fibrosis and progressive renal or liver dysfunction are common findings. ALMS1 encodes a large ubiquitously expressed protein that is associated with the centrosome and the basal body of primary cilium.
CURRENT RESEARCH
The localisation of ALMS1 to the ciliary basal body suggests its contribution to ciliogenesis and/or normal ciliary function, or centriolar stability. ALMS1 regulate glucose transport through the actin cytoskeleton, which plays an important role in insulin-stimulated GLUT4 transport. Both extreme IR and β-cell failure are the two determinant factors responsible for the development of glucose metabolism alterations in ALMS.
TREATMENT
Currently, there is no known cure for ALMS other than managing the underlying systemic diseases. When possible, individuals with ALMS and families should be referred to a centre of expertise and followed by a multidisciplinary team. Lifestyle modification, aerobic exercise and dietary induced weight loss are highly recommended as primary treatment for ALMS patients with T2DM and obesity.
CONCLUSION
Managing a rare disease requires not only medical care but also a support network including patient associations.
Topics: Alstrom Syndrome; Cell Cycle Proteins; Child, Preschool; Diabetes Mellitus, Type 2; Humans; Insulin Resistance; Obesity; Rare Diseases
PubMed: 33566311
DOI: 10.1007/s12020-021-02643-y -
Nature Reviews. Endocrinology Feb 2011Genetic causes of obesity include the ciliopathies Alström syndrome and Bardet-Biedl syndrome. In these disorders, mutations cause dysfunction of the primary cilium, an... (Review)
Review
Genetic causes of obesity include the ciliopathies Alström syndrome and Bardet-Biedl syndrome. In these disorders, mutations cause dysfunction of the primary cilium, an organelle involved in intracellular and intercellular sensing and signaling. Alström syndrome is an autosomal-recessive disorder caused solely by mutations in ALMS1. By contrast, Bardet-Biedl syndrome is caused by mutations in at least 14 genes involved in primary cilium function. Despite equivalent levels of obesity, patients with Alström syndrome are more likely than those with Bardet-Biedl syndrome to develop childhood type 2 diabetes mellitus (T2DM), suggesting that ALMS1 might have a specific role in β-cell function and/or peripheral insulin signaling pathways. How mutations in genes that encode proteins involved in primary cilium function lead to the clinical phenotypes of these syndromes is being revealed by work in mutant mouse models. With the aid of these models, insights are being obtained into the pathogenic mechanisms that underlie obesity, insulin resistance and T2DM. Research into ciliopathies, including Alström syndrome and Bardet-Biedl syndrome, should lead not only to improved treatments for individuals with these genetic disorders, but also to improved understanding of the cellular pathways involved in other common causes of obesity and T2DM.
Topics: Alstrom Syndrome; Animals; Bardet-Biedl Syndrome; Cell Cycle Proteins; Diabetes Mellitus, Type 2; Humans; Mutation; Obesity; Proteins
PubMed: 21135875
DOI: 10.1038/nrendo.2010.210 -
Molecular Diagnosis & Therapy Dec 2020Obesity represents a major health burden to both developed and developing countries. Furthermore, the incidence of obesity is increasing in children. Obesity contributes... (Review)
Review
Obesity represents a major health burden to both developed and developing countries. Furthermore, the incidence of obesity is increasing in children. Obesity contributes substantially to mortality in the United States by increasing the risk for type 2 diabetes, cardiovascular-related diseases, and other comorbidities. Despite environmental changes over past decades, including increases in high-calorie foods and sedentary lifestyles, there is very clear evidence of a genetic predisposition to obesity risk. Childhood obesity cases can be categorized in one of two ways: syndromic or non-syndromic. Syndromic obesity includes disorders such as Prader-Willi syndrome, Bardet-Biedl syndrome, and Alström syndrome. Non-syndromic cases of obesity can be further separated into rarer instances of monogenic obesity and much more common forms of polygenic obesity. The advent of genome-wide association studies (GWAS) and next-generation sequencing has driven significant advances in our understanding of the genetic contribution to childhood obesity. Many rare and common genetic variants have been shown to contribute to the heritability in obesity, although the molecular mechanisms underlying most of these variants remain unclear. An important caveat of GWAS efforts is that they do not strictly represent gene target discoveries, rather simply the uncovering of robust genetic signals. One clear example of this is with progress in understanding the key obesity signal harbored within an intronic region of the FTO gene. It has been shown that the non-coding region in which the variant actually resides in fact influences the expression of genes distal to FTO instead, specifically IRX3 and IRX5. Such discoveries suggest that associated non-coding variants can be embedded within or next to one gene, but commonly influence the expression of other, more distal effector genes. Advances in genetics and genomics are therefore contributing to a deeper understanding of childhood obesity, allowing for development of clinical tools and therapeutic agents.
Topics: Child; Genetic Predisposition to Disease; Genetic Variation; Genome-Wide Association Study; Humans; Multifactorial Inheritance; Pediatric Obesity; Risk Factors
PubMed: 33006084
DOI: 10.1007/s40291-020-00496-1