New variants of ALMS1 gene and familial Alström syndrome case series.

OBJECTIVES: To report two new variants of ALMS1 gene and to discuss the audiological evolution and clinical phenotype in two pairs of siblings with Alström syndrome. REPORT: This paper is a multi-disciplinary diagnostic evaluation, with genetic and audiological analysis that aims to report two new variants of the ALMS1 gene and to discuss the audiological evolution and clinical phenotype in a case series of patients with familial Alström syndrome. Therefore, we describe 4 cases presenting a complete audiometric profile of two pairs of unrelated siblings, to provide a better understanding of this very rare disease. Additionally, the present study identified two heterozygous mutations in the ALMS1 gene. CONCLUSION: This Clinical Capsule Report highlights the importance of audiological monitoring throughout the development of patients with Alström syndrome. The two variants found were not previously reported in the literature, which expands the spectrum of ALMS1 variants in Alström syndrome.

New variants of ALMS1 gene and familial Alström syndrome case series

Abstract Objectives To report two new variants of ALMS1 gene and to discuss the audiological evolution and clinical phenotype in two pairs of siblings with Alström syndrome. Report This paper is a multi-disciplinary diagnostic evaluation, with genetic and audiological analysis that aims to report two new variants of the ALMS1 gene and to discuss the audiological evolution and clinical phenotype in a case series of patients with familial Alström syndrome. Therefore, we describe 4 cases presenting a complete audiometric profile of two pairs of unrelated siblings, to provide a better understanding of this very rare disease. Additionally, the present study identified two heterozygous mutations in the ALMS1 gene. Conclusion This Clinical Capsule Report highlights the importance of audiological monitoring throughout the development of patients with Alström syndrome. The two variants found were not previously reported in the literature, which expands the spectrum of ALMS1 variants in Alström syndrome.

Morphological and functional findings in Alström syndrome: a study of two families / Achados morfológicos e funcionais na síndrome de Alström: um estudo de duas famílias

ABSTRACT Alström syndrome is a rare disorder characterized by mutations to the ALMS1 gene and clinical findings of childhood obesity, diabetes mellitus, dilated cardiomyopathy, sensorineural hearing loss, and progressive cone-rod dystrophy, which may result in blindness. Ocular manifestations occur in the first decade of life with nystagmus, blepharospasm, and photophobia leading to progressive and severe reductions in visual acuity. This study describes the retinal structure and functional aspects of four patients (8 eyes) from two different families as determined by optical coherence tomography (OCT), fundus autofluorescence, and full-field electroretinography. There was a correlation between morphological and functional findings, evidenced by typical funduscopic changes of retinal dystrophy in spectral domain-OCT and electrophysiological analyses. Foveal characteristics include a single layer of undifferentiated photoreceptors with retinal disorganization mainly from external segments, in agreement with previous reports in the literature. Fundus autofluorescence showed areas of hyperautofluorescence interspersed by hypoautofluorescence dots suggesting, respectively, involvement and atrophy of retinal pigmented epithelial cells in the macular zone. Electroretinographic analyses showed early dysfunction of the cones followed by rapid rod deterioration.

RESUMO A síndrome de Alström é uma doença rara caracterizada por mutações no gene AMLS 1 e achados clínicos de obesidade infantil, diabetes mellitus, cardiomiopatia dilatada, surdez neurossensorial e distrofia de cones e bastonetes progressiva, que podem resultar em cegueira. Manifestações oftalmológicas ocorrem na primeira década de vida com nistagmo, blefaroespasmo e fotofobia, levando a reduções progressivas e graves na acuidade visual. Este estudo descreve a estrutura da retina e os aspectos funcionais de quatro pacientes (oito olhos) de duas famílias dis tintas, conforme determinado por tomografia de coerência óptica, autoflourescência de fundo de olho e eletrorretinograma de campo total. Houve correlação entre os achados morfológicos e funcionais evidenciados por alterações fundoscópicas típicas da distrofia retiniana no domínio espectral-OCT e análises eletrofisiológicas. As características foveais incluem uma única camada de fotorreceptores indiferenciados com desorganização retiniana principalmente nos segmentos externos, de acordo com relatos prévios da literatura. A autofluorescência de fundo mostrou áreas de hiperautofluorescência, sugerindo, respectivamente, envolvimento e atrofia das células do epitélio pigmentar da retina na região macular. Análises eletrorretinográficas mostram disfunção precoce de cones, seguida de rápida deteriorização da haste.

A Nonsense ALMS1 Mutation Underlies Alström Syndrome in an Extended Mennonite Kindred Settled in North Mexico.

AIM: Alström syndrome (AS) is a rare autosomal recessive multisystem disease caused by biallelic mutations in ALMS1, a gene encoding a widely expressed centrosomal/basal body protein. Although more than 200 pathogenic mutations in ALMS1 have been identified to date in AS patients from various ethnic populations, there are very few reports of ALMS1 founder mutations in isolated populations. Our aim was to describe the molecular characterization of a cohort of AS patients from an extended inbred Mennonite kindred settled in Mexico. METHODS: Genetic study included polymerase chain reaction amplification and direct nucleotide sequencing of the entire ALMS1 gene in DNA from seven related AS patients. RESULTS: A homozygous single-nucleotide c.10480C>T substitution in exon 16, predicting a p.Q3494* nonsense mutation, was identified in all affected subjects. CONCLUSIONS: To our knowledge, this is the first demonstration of a high prevalence of AS in Mennonites, a population group maintaining high levels of consanguineous marriage in their communities. Our findings provide an example of genetic isolation and consanguinity causing a high prevalence of AS and offer the opportunity for early clinical interventions and for genetic counseling of at-risk couples in this community.