Characterization of the IGF system in 15 patients with Alström syndrome

Alstrom syndrome with classical findings: a rare case report of monogenic ciliopathy co-occurrence in twins

Introduction and importance

Alstrom syndrome is one of the rarest monogenic ciliopathy belonging to autosomal recessive disorder. The pathophysiology of Alstrom syndrome is not well understood but based upon the available medical literature its mechanism can be linked with recessive mutation in Alstrom syndrome 1(ALSM1) gene resulting in various multiple organ involvement and poor prognosis. Moreover the co-occurrence of such syndrome simultaneously in twins in same period of time is considered rare.

Case presentation

Monochorionic diamniotic twins male born to healthy parents with significant antenatal and natal history along with decreased vision in both eyes in both twins since neonatal period. Throughout the childhood the disease progressed without any confirmatory diagnosis during which the twins underwent simultaneous multiple systemic involvement such as legal blindness in both twins at the age of 11 years, insulin resistance and features of diabetes mellitus, sensorineural hearing loss, subclinical hypothyroidism and various deranged metabolic panels. Certain diagnosis of Alstrom syndrome was made at the age of 16 years in both twins after whole-exome sequencing.

Clinical discussion

Based on genetic profile alstrom syndrome is a unique diagnosis. Along with its multi-organ involvement features, its progression and prognosis should also be looked upon while diagnosis and management in such syndromic patients. The diagnostic delay in such cases is also a matter of concern which can result in further delay in halting adverse effects of the disease itself. The multidisciplinary approach with involvement of endocrionologist, ophthalmologist and audiologist can bring upon improvement in quality of life of the patients.

Conclusion

With the prevalence of 1 in million cases Alstrom Hallgren syndrome is one of the rare genetic disorder with poor prognosis. In our case we present classical findings in twins who were diagnosed as Alstrom syndrome concurrently and further diseases progressed simultaneously.

Very high bone mineral density in a monogenic form of obesity-associated insulin resistance

INTRODUCTION

Alström syndrome (ALMS) is an ultra-rare metabolic disorder caused by biallelic loss-of-function in the Alms1 gene which encodes a ubiquitously expressed centrosomal protein of the primary cilium. Although ALMS is characterised by several metabolic and hormonal dysfunctions that can lead to an increased risk of developing osteoporosis and bone fracture, an increased BMD have been observed. The aim of this study was to characterise the anthropometric, clinical, genetic and densitometric features of bone health in a large adult UK cohort of subjects with ALMS.

METHODS

Twenty-three patients with ALMS and 23 age-matched male control subjects were recruited. Lumbar spine (LS) and total hip (TH) bone mineral density (BMD) were evaluated by DXA in all subjects. A CT scan to assess the spinal bone architecture was performed in ALMS patients with raised lumbar density. Blood analysis for biochemical parameters and thyroid and sex hormones was performed in all ALMS patients.

RESULTS

LS Z-score levels were higher than +2 SD in 35% of all ALMS study participants, of whom 75% were men and 25% were women. TH Z-scores were higher than +1 SD 13% of patients and all of them have higher than expected lumbar Z-score. An extremely high BMD was found in two of the oldest patients (LS Z-score +10.8 and +15.3 SD).

CONCLUSION

ALMS patients tend to have high levels of BMD that increase with age, in particular of the trabecular bones. Although obesity and lifelong IR can be responsible for the increase in BMD, at least in part, of a possible signalling role of Alms1 protein as a bone-forming factor is plausible.

Consensus clinical management guidelines for Alström syndrome

Alström Syndrome (ALMS) is an ultra-rare multisystem genetic disorder caused by autosomal recessive variants in the ALMS1 gene, which is located on chromosome 2p13. ALMS is a multisystem, progressive disease characterised by visual disturbance, hearing impairment, cardiomyopathy, childhood obesity, extreme insulin resistance, accelerated non-alcoholic fatty liver disease (NAFLD), renal dysfunction, respiratory disease, endocrine and urologic disorders. Clinical symptoms first appear in infancy with great variability in age of onset and severity. ALMS has an estimated incidence of 1 case per 1,000,000 live births and ethnically or geographically isolated populations have a higher-than-average frequency. The rarity and complexity of the syndrome and the lack of expertise can lead to delayed diagnosis, misdiagnosis and inadequate care. Multidisciplinary and multiprofessional teams of experts are essential for the management of patients with ALMS, as early diagnosis and intervention can slow the progression of multi-organ dysfunctions and improve patient quality of life.These guidelines are intended to define standard of care for patients suspected or diagnosed with ALMS of any age. All information contained in this document has originated from a systematic review of the literature and the experiences of the authors in their care of patients with ALMS. The Appraisal of Guidelines for Research & Evaluation (AGREE II) system was adopted for the development of the guidelines and for defining the related levels of evidence and strengths of recommendations.These guidelines are addressed to: a) specialist centres, other hospital-based medical teams and staffs involved with the care of ALMS patients, b) family physicians and other primary caregivers and c) patients and their families.

Obesity an overview: Genetic conditions and recent developments in therapeutic interventions

Obesity is a complex disorder that is linked to many coexisting disorders. Recent epidemiological data have suggested that the prevalence of obesity is at an all-time high, growing to be one of the world's biggest problems. There are several mechanisms on how individuals develop obesity which includes genetic and environmental factors. Not only does obesity contribute to other health issues but it also greatly affects the quality of life, physical ability, mental strength and imposes a huge burden in terms of healthcare costs. Along with that, obesity is associated with the risk of mortality and has been shown to reduce the median survival rate. Obesity is basically when the body is not able to balance energy intake and output. When energy intake exceeds energy expenditure, excess calories will be stored as fat leading to weight gain and eventually obesity. The therapeutic market for treating obesity is composed of many different interventions from lifestyle intervention, surgical procedures to pharmacotherapeutic approaches. All of these interventions have their respective benefits and disadvantages and are specifically prescribed to a patient based on the severity of their obesity as well as the existence of other health conditions. This review discusses the genetic and environmental causes of obesity along with the recent developments in anti-obesity therapies.

Pituitary morphovolumetric changes in Alström syndrome

PURPOSE

Alström syndrome (AS) is a rare monogenic ciliopathy characterized by cone-code dystrophy, leading to early blindness, and obesity. Early endocrinological dysfunctions, especially growth hormone deficiency and hypogonadism, are detected in about half of AS patients. This MRI study investigates the presence of pituitary gland abnormalities in a large cohort of AS patients.

METHODS

Pituitary morphological changes (gland flattening with partial or total empty sella) were evaluated on midsagittal high-resolution T1-weighted images of 32 AS patients (mean-age 23.2±9.4 years; range: 6-45, 15 females) and 21 unrelated healthy subjects (mean age 23.2±11.2 years; range: 6-43; 10 females).

RESULTS

Among AS patients, 11/32 (34%) had total empty sella and 6/32 (19%) partial empty sella, while 3/21 (14%) of controls had partial empty sella and none presented with total empty sella (P<0.005). AS patients harboring a total or partial empty sella did not differ from those with normal pituitary gland for gender (P=0.98), BMI (P=0.10) or visual impairment (P=0.21), while the presence of empty sella was associated with an older age (P=0.007) being especially frequent above the age of 30.

CONCLUSIONS

Total or partial empty sella appears commonly during the course of AS. Pituitary gland flattening might represent the morphological underpinning of subtle endocrinologic dysfunctions and raises the need to further investigate the pituitary function in this rare ciliopathy.

Alström syndrome: current perspectives

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.

Alström Syndrome: Mutation Spectrum of ALMS1

Alström Syndrome (ALMS), a recessive, monogenic ciliopathy caused by mutations in ALMS1, is typically characterized by multisystem involvement including early cone-rod retinal dystrophy and blindness, hearing loss, childhood obesity, type 2 diabetes mellitus, cardiomyopathy, fibrosis, and multiple organ failure. The precise function of ALMS1 remains elusive, but roles in endosomal and ciliary transport and cell cycle regulation have been shown. The aim of our study was to further define the spectrum of ALMS1 mutations in patients with clinical features of ALMS. Mutational analysis in a world-wide cohort of 204 families identified 109 novel mutations, extending the number of known ALMS1 mutations to 239 and highlighting the allelic heterogeneity of this disorder. This study represents the most comprehensive mutation analysis in patients with ALMS, identifying the largest number of novel mutations in a single study worldwide. Here, we also provide an overview of all ALMS1 mutations identified to date.

Elevation of insulin-like growth factor binding protein-2 level in Pallister-Killian syndrome: implications for the postnatal growth retardation phenotype

Pallister-Killian syndrome (PKS) is a multi-system developmental disorder caused by tetrasomy 12p that exhibits tissue-limited mosaicism. Probands with PKS often demonstrate a unique growth profile consisting of macrosomia at birth with deceleration of growth postnatally. We have previously demonstrated that cultured skin fibroblasts from PKS probands have significantly elevated expression of insulin-like growth factor binding protein-2 (IGFBP2). To further evaluate the role of IGFBP2 in PKS, the amount of IGFBP2 secreted from cultured skin fibroblast cell lines and serum IGFBP2 levels were measured in probands with PKS. Approximately 60% of PKS fibroblast cell lines secreted higher levels of IGFBP2 compared to control fibroblasts, although the remaining 40% of PKS samples produced comparable level of IGFBP2 to that of control fibroblasts. Serum IGFBP2 levels were also measured in PKS probands and were elevated in 40% of PKS probands. PKS probands with elevated IGFBP2 manifested with severe postnatal growth retardation. IGFBPs are the family of related proteins that bind IGFs with high affinity and are typically thought to attenuate IGF action. We suggest that elevated IGFBP2 levels might play a role in the growth retardation phenotype of PKS.

GLUT4 defects in adipose tissue are early signs of metabolic alterations in Alms1GT/GT, a mouse model for obesity and insulin resistance

Dysregulation of signaling pathways in adipose tissue leading to insulin resistance can contribute to the development of obesity-related metabolic disorders. Alström Syndrome, a recessive ciliopathy, caused by mutations in ALMS1, is characterized by progressive metabolic alterations such as childhood obesity, hyperinsulinemia, and type 2 diabetes. Here we investigated the role of Alms1 disruption in AT expansion and insulin responsiveness in a murine model for Alström Syndrome. A gene trap insertion in Alms1 on the insulin sensitive C57BL6/Ei genetic background leads to early hyperinsulinemia and a progressive increase in body weight. At 6 weeks of age, before the onset of the metabolic disease, the mutant mice had enlarged fat depots with hypertrophic adipocytes, but without signs of inflammation. Expression of lipogenic enzymes was increased. Pre-adipocytes isolated from mutant animals demonstrated normal adipogenic differentiation but gave rise to mature adipocytes with reduced insulin-stimulated glucose uptake. Assessment of whole body glucose homeostasis revealed glucose intolerance. Insulin stimulation resulted in proper AKT phosphorylation in adipose tissue. However, the total amount of glucose transporter 4 (SLC4A2) and its translocation to the plasma membrane were reduced in mutant adipose depots compared to wildtype littermates. Alterations in insulin stimulated trafficking of glucose transporter 4 are an early sign of metabolic dysfunction in Alström mutant mice, providing a possible explanation for the reduced glucose uptake and the compensatory hyperinsulinemia. The metabolic signaling deficits either reside downstream or are independent of AKT activation and suggest a role for ALMS1 in GLUT4 trafficking. Alström mutant mice represent an interesting model for the development of metabolic disease in which adipose tissue with a reduced glucose uptake can expand by de novo lipogenesis to an obese state.

Alström syndrome is associated with short stature and reduced GH reserve

INTRODUCTION

Alström syndrome (ALMS) is a rare autosomal recessive monogenic disease included in an emerging class of genetic disorders called 'ciliopathies' and is likely to impact the central nervous system as well as metabolic and endocrine function. Individuals with ALMS present clinical features resembling a growth hormone deficiency (GHD) condition, but thus far no study has specifically investigated this aspect in a large population.

MATERIAL AND METHODS

Twenty-three patients with ALMS (age, 1-52 years; 11 males, 12 females) were evaluated for anthropometric parameters (growth charts and standard deviation score (SDS) of height, weight, BMI), GH secretion by growth hormone-releasing hormone + arginine test (GHRH-arg), bone age, and hypothalamic-pituitary magnetic resonance imaging (MRI). A group of 17 healthy subjects served as controls in the GH secretion study. Longitudinal retrospective and prospective data were utilized.

RESULTS

The length-for-age measurements from birth to 36 months showed normal growth with most values falling within -0·67 SDS to +1·28 SDS. A progressive decrease in stature-for-age was observed after 10 years of age, with a low final height in almost all ALMS subjects (>16-20 years; mean SDS, -2·22 ± 1·16). The subset of 12 patients with ALMS tested for GHRH-arg showed a significantly shorter stature than age-matched controls (154·7 ± 10·6 cm vs 162·9 ± 4·8 cm, P = 0·009) and a mild increase in BMI (Kg/m(2) ) (27·8 ± 4·8 vs 24·1 ± 2·5, P = 0·007). Peak GH after GHRH-arg was significantly lower in patients with ALMS in comparison with controls (11·9 ± 6·9 μg/l vs 86·1 ± 33·2 μg/l, P < 0·0001). Severe GHD was evident biochemically in 50% of patients with ALMS. The 10 adult ALMS patients with GHD showed a reduced height in comparison with those without GHD (149·7 ± 6·2 cm vs 161·9 ± 9·2 cm, P = 0·04). MRIs of the diencephalic and pituitary regions were normal in 11 of 12 patients. Bone age was advanced in 43% of cases.

CONCLUSIONS

Our study shows that 50% of nonobese ALMS patients have an inadequate GH reserve to GHRH-arg and may be functionally GH deficient. The short stature reported in ALMS may be at least partially influenced by impairment of GH secretion.

Alström syndrome: cardiac magnetic resonance findings

BACKGROUND

Alström Syndrome (ALMS) is an extremely rare multiorgan disease caused by mutations in ALMS1. Dilated cardiomyopathy (DCM) is a common finding but only one series has been investigated by Cardiac Magnetic Resonance (CMR).

METHODS

Eight genetically proven ALMS patients (ages 11-41) underwent CMR performed by standard cine steady state, T1, T2 and late gadolinium enhancement (LGE) sequences. Ejection fraction (EF), Diastolic Volume (EDV) and Systolic Volume normalized for body surface area (ESV), and mass indices were determined, as well as EDV/Mass ratio, an index expressing the adequacy of cardiac mass to heart volume. Regional fibrosis was assessed by LGE; diffuse fibrosis was measured by a TI scout sequence acquired at 5, 10 and 15 min after gadolinium by comparing inversion time values (TI) at null time in ALMS and control group.

RESULTS

In one patient severe DCM was present with diffuse LGE. There were seven cases without clinical DCM. In these patients, EF was at lower normal limits or slightly reduced and ESV index increased; six patients had decreased mass index and EDV/Mass ratio. Mild regional non ischemic fibrosis was detected by LGE in three cases; diffuse fibrosis was observed in all cases, as demonstrated by shorter TI values in ALMS in comparison with controls (5 min: 152 ± 12 vs 186 ± 16, p 0.0002; 10 min: 175 ± 8 vs 204 ± 18, p 0.0012; 15 min: 193 ± 9 vs 224 ± 16, p 0.0002).

CONCLUSIONS

Cardiac involvement in ALMS is characterized by progressive DCM, associated with systolic dysfunction, myocardial fibrosis and reduced myocardial mass.

Endocrine manifestations related to inherited metabolic diseases in adults

Most inborn errors of metabolism (IEM) are recessive, genetically transmitted diseases and are classified into 3 main groups according to their mechanisms: cellular intoxication, energy deficiency, and defects of complex molecules. They can be associated with endocrine manifestations, which may be complications from a previously diagnosed IEM of childhood onset. More rarely, endocrinopathies can signal an IEM in adulthood, which should be suspected when an endocrine disorder is associated with multisystemic involvement (neurological, muscular, hepatic features, etc.). IEM can affect all glands, but diabetes mellitus, thyroid dysfunction and hypogonadism are the most frequent disorders. A single IEM can present with multiple endocrine dysfunctions, especially those involving energy deficiency (respiratory chain defects), and metal (hemochromatosis) and storage disorders (cystinosis). Non-autoimmune diabetes mellitus, thyroid dysfunction and/or goiter and sometimes hypoparathyroidism should steer the diagnosis towards a respiratory chain defect. Hypogonadotropic hypogonadism is frequent in haemochromatosis (often associated with diabetes), whereas primary hypogonadism is reported in Alström disease and cystinosis (both associated with diabetes, the latter also with thyroid dysfunction) and galactosemia. Hypogonadism is also frequent in X-linked adrenoleukodystrophy (with adrenal failure), congenital disorders of glycosylation, and Fabry and glycogen storage diseases (along with thyroid dysfunction in the first 3 and diabetes in the last). This is a new and growing field and is not yet very well recognized in adulthood despite its consequences on growth, bone metabolism and fertility. For this reason, physicians managing adult patients should be aware of these diagnoses.

Alström syndrome: genetics and clinical overview

Alström syndrome is a rare autosomal recessive genetic disorder characterized by cone-rod dystrophy, hearing loss, childhood truncal obesity, insulin resistance and hyperinsulinemia, type 2 diabetes, hypertriglyceridemia, short stature in adulthood, cardiomyopathy, and progressive pulmonary, hepatic, and renal dysfunction. Symptoms first appear in infancy and progressive development of multi-organ pathology leads to a reduced life expectancy. Variability in age of onset and severity of clinical symptoms, even within families, is likely due to genetic background.Alström syndrome is caused by mutations in ALMS1, a large gene comprised of 23 exons and coding for a protein of 4,169 amino acids. In general, ALMS1 gene defects include insertions, deletions, and nonsense mutations leading to protein truncations and found primarily in exons 8, 10 and 16. Multiple alternate splice forms exist. ALMS1 protein is found in centrosomes, basal bodies, and cytosol of all tissues affected by the disease. The identification of ALMS1 as a ciliary protein explains the range of observed phenotypes and their similarity to those of other ciliopathies such as Bardet-Biedl syndrome.Studies involving murine and cellular models of Alström syndrome have provided insight into the pathogenic mechanisms underlying obesity and type 2 diabetes, and other clinical problems. Ultimately, research into the pathogenesis of Alström syndrome should lead to better management and treatments for individuals, and have potentially important ramifications for other rare ciliopathies, as well as more common causes of obesity and diabetes, and other conditions common in the general population.

Alström syndrome: insights into the pathogenesis of metabolic disorders

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.

Protection from clinical peripheral sensory neuropathy in Alström syndrome in contrast to early-onset type 2 diabetes

OBJECTIVE

Alström syndrome, with type 2 diabetes, and blindness could confer a high risk of foot ulceration. Clinical testing for neuropathy in Alström syndrome and matched young-onset type 2 diabetic subjects was therefore undertaken.

RESEARCH DESIGN AND METHODS

Fifty-eight subjects with Alström syndrome (18 insulin-resistant nondiabetic and 40 diabetic; aged 8-43 years) and 30 young-onset diabetic subjects (aged 13-35 years) were studied. Neuropathy symptom questionnaires were administered. Graded monofilament and 128-MHz tuning fork vibration perception were assessed in both feet.

RESULTS

Neuropathic symptoms, loss of monofilament, and/or vibration perception were reported by 12 of the 30 young-onset type 2 diabetic subjects (6 had neuropathic ulceration) but none of the subjects with Alström syndrome.

CONCLUSIONS

The striking preservation of protective foot sensation in Alström syndrome may provide a clue to the causes of differential susceptibility to neuropathy in the wider diabetic population.

Impaired IGF1-GH axis and new therapeutic options in Alström Syndrome patients: a case series

Background

Defects of the primary cilium and its anchoring structure, the basal body, cause a number of human genetic disorders, collectively termed ciliopathies: primary ciliary dyskinesia, Bardet-Biedl syndrome, polycystic kidney and liver disease, nephronophthisis, Alström syndrome, Meckel-Gruber syndrome and some forms of retinal degeneration.

Alström syndrome is an extremely rare, autosomal recessive genetic disorder characterized by a group of signs and symptoms including infantile onset dilated cardiomyopathy, blindness, hearing impairment/loss, obesity, diabetes, hepatic and renal dysfunction.

Because adult growth hormone deficiency and Alström Syndrome share some clinical and metabolic features, we studied the GH-IGF1 axis, using MRI techniques and dynamic tests in 3 unrelated patients with Alström syndrome.

Case presentation

The patients were hospitalized and the growth hormone stimulatory tests were made, as well as brain MRI. Insulin provocative test revealed a severe GH deficiency in these patients, defined by a peak response to insulin-induced hypoglycemia less than 3 ng/dl and IGF1 concentrations less than – 2SDS.

We didn't find multiple pituitary hormone deficiency and we noticed only a severe GH deficiency in all three patients. The MRI study of the diencephalic and pituitary region was suggestive for the diagnosis of empty sella in one patient.

One patient received Recombinant-GH replacement for one year with very good results, one underwent a gastric sleeve with a satisfactory outcome, one patient died due to the progression of the cardiac myopathy.

Conclusion

Future studies are needed to assses if the substitution therapy with Recombinant Growth hormone is cost-effective and without risk in such patients with Alström Syndrome and severe insulin resistance, despite our good results in one patient. Also, careful clinical and genetic studies can contribute to a better understanding of the evolution after different therapeutical attempt in the complex disorders such as Alström Syndrome.

Monitoring clinical quality in rare disease services--experience in England

After some well-publicised problems with paediatric cardiac surgery, there has been great interest in England in monitoring clinical quality in specialised medical services. The National Commissioning Group plans, funds and monitors a set of highly specialised services for the National Health Service in England. We have developed systems for monitoring clinical quality that perform two interrelated but distinct functions: performance measurement and performance improvement. The aim is to collect information on all patients seen during each year--a 100% consecutive case series. Generally, there is no conceptual difficulty identifying an appropriate outcome for surgical interventions: the indication for surgery usually defines the outcome to monitor. This is not so for the medical and psychiatric services, where the relevant outcome to monitor is sometimes not obvious. There are a number of problems in interpreting, and acting on, outcome data for rare conditions and treatments. These problems include statistical problems due to small numbers, the need to risk adjust data and coding problems.

Alstrom syndrome (OMIM 203800): a case report and literature review

Background

Alstrom syndrome (AS) is a rare autosomal recessive disease characterized by multiorgan dysfunction. The key features are childhood obesity, blindness due to congenital retinal dystrophy, and sensorineural hearing loss. Associated endocrinologic features include hyperinsulinemia, early-onset type 2 diabetes, and hypertriglyceridemia. Thus, AS shares several features with the common metabolic syndrome, namely obesity, hyperinsulinemia, and hypertriglyceridemia. Mutations in the ALMS1 gene have been found to be causative for AS with a total of 79 disease-causing mutations having been described.

Case presentation

We describe the case of a 27-year old female from an English (Caucasian) kindred. She had been initially referred for hypertriglyceridemia, but demonstrated other features suggestive of AS, including blindness, obesity, type 2 diabetes, renal dysfunction, and hypertension. DNA analysis revealed that she is a compound heterozygote with two novel mutations in the ALMS1 gene – H3882Y and V424I. Examination of her family revealed that her phenotypically unaffected mother and younger sister also had heterozygous mutations in the ALMS1 gene. In addition to presenting these novel molecular findings for AS, we review the clinical and genetic features of AS in the context of our case.

Conclusion

Two novel mutations in the ALMS1 gene causative for AS have been reported here, thereby increasing the number of reported mutations to 81 and providing a wider basis for mutational screening among affected individuals.

Alström syndrome

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.