ALSTROM HALLGREN SYNDROME WITH CLASSICAL FINDINGS: A RARE CASE REPORT OF MONOGENIC CILIOPATHY CO-OCCURRENCE IN TWINS.Clinical Message: With the prevalence of 1 in million cases Alstorm 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 .Keywords: Alstrom Hallgren syndrome, monogenic ciliopathy, twinsCorresponding Author :1Sagun ghimire,KIST medical college and Teaching Hospital, Gwarko, Lalitpur, NepalSagunghimire01@gmail.comCo-authors:2Suman simkhada, KIST medical college and teaching hospital,gwarko, lalitpur, Nepalsimkhadasuman@gmail.com3Samir Thapa, KIST medical college and teaching hospital, gwarko,lalitpur, NepalThapasamir32@gmail.com4Kiran Ghising, KIST medical college and teaching hospital, gwarko,lalitpur, NepalKiran.email@example.com . INTRODUCTION:Alström syndrome is a rare autosomal recessive genetic disorder,thought to have a prevalence of less than one per million in the general population. It is characterized by the progressive development of multi-organpathology . It is caused by recessive mutations in ALMS1 (Chr 2q13). Although its function is not completely understood, evidence to date suggests that ALMS1 plays roles in ciliary function, cell cycle regulation, endosomal trafficking, cell migration, and extracellular matrix production . Diagnosis of Alström Syndrome can be difficult because some features begin at birth and others emerge as the child develops. There is considerable variation both within and among families. The major phenotypes usually observed in children with Alström Syndrome include cone–rod retinal dystrophy beginning in infancy and leading to eventual juvenile blindness, sensorineural hearing impairment, insulin resistance, and obesity. In some cases, infants present with congestive heart failure (CHF) due to dilated cardiomyopathy (DCM). As patients reach adolescence, more of the major phenotypes develop, including type 2 diabetes mellitus (T2DM), hypertriglyceridemia, and adolescent-onset DCM. Short stature, scoliosis, alopecia, and male hypogonadism and hyperandrogenism in female patients may be present when patients reach adulthood. Pulmonary, hepatic, and renal phenotypes are progressive. Fibrosis in multiple organs has been described . Currently there are no specific treatments for Alström syndrome that can cure the disease, prevent the complications, or reverse the complications. A multidisciplinary approach is currently preferred to detect, predict, and treat the complications of Alström syndrome. The article is presented in accordance with CARE guidelines for case reports. Here, we present a case of twin siblings with signs and symptoms consistent with AS and associated with two AMLS1 variants.2. CASE SUMMARYPatients Demography :In this report we describe monochorionic, diamniotic twin boys who were born pre term at 36 weeks to a healthy 28 year old mother and healthy 32 year old father, with natal history of low birth weight of in one twin and in another twin with APGAR score of 6\10 and 7\10 and post natal history of raised total serum bilirubin for which both twins were kept under phototherapy. There is no history of delay in attainment of age related milestones . Parents are of Asian heritage who deny consanguinity, both alive and well as well as two twins siblings currently aged 16 years . The family structure is outlined in( Figure 1). Family history was not significant for any genetic disease on the paternal and maternal side.Clinical Evaluation :On physical examination, there was evidence of central obesity in both twins with the body mass index ( in both) being 34.9 kg/m2. Their blood pressure was within normal percentile with a regular pulse of 80 beats per minute. Behaviorally, they do not demonstrates several features concerning for autism spectrum disorder, including poor eye contact, lack of a social smile, and disinterest in social interaction. Their weight since birth has been seen to in increasing trend, and height within mid parental range. There was no evidence of poly- or syndactyly or any other features suggestive of Bardet-Biedl syndrome. Features of hirsutism was also absent on the face, abdomen, and arms. There was significant history of decreased vision in both eyes since neonatal period .Both the twins presented at four years of age with visual symptoms suggestive of photosensitivity. There was features suggestive of rotatory nystagmus . Amsler grid and color vision tests were normal. Visual field revealed concentric contraction in both eyes. The fundoscopy showed pale optic discs, atrophic maculopathy, golden appearance of peripheral and midperipheral fundus, coarser pigmentary changes with a ”bone-spicule” configuration and arteriolar narrowing. The red free pictures demonstrated the atrophy of internal retinal layers and the infrared pictures revealed the atrophy of the external layers of the retina in posterior pole of the fundus. The flash ERG showed reduced amplitude of photopic and scotopic b-wave. The multifocal ERG demonstrated the normal function of the central retina. revealed decreased Arden ratio in both eyes. The pattern VEP revealed the P100 amplitude reduction by 80% and elongation of latency by 120% in the right eye and normal in the left eye. Subsequent ophthalmologic exam showed visual acuity of counting finger from 2 and half meter binocularly only due to high hyperopia with amblyopia. The findings were consistent with cone-rod dystrophy through electroretinography (ERG). Subsequently there was progressive visual loss and legal blindness was declared to both of the twins at the age of 11 years. The cardiovascular examination was unremarkable with no any significant Echocardiography and electrocardiography findings . There was not any features suggestive of congestive heart failure, myocarditis, dilated cardiomyopathy. Cardiac catheterization and Endomyocardial biopsy were not done . A comprehensive systemic panel did not identify any disease causing mutations and screening for evidence of metabolic and mitochondrial diseases was negative. The patient also showed features such as weight loss, polyuria, polydipsia, predilection to sweet foods.