OBJECTIVE: To explore the genetic basis for 7 patients with Alström syndrome. METHODS: DNA was extracted from peripheral blood samples of the patients and their parents. Whole exome sequencing was carried out for the patients. Suspected variant was verified by Sanger sequencing and bioinformatic analysis. RESULTS: Genetic testing revealed 12 variants of the ALMS1 gene among the 7 patients, including 7 nonsense and 5 frameshift variants, which included c.5418delC (p.Tyr1807Thrfs*23), c.10549C>T (p.Gln3517*), c.9145dupC (p.Thr3049Asnfs*12), c.10819C>T (p.Arg3607*), c.5701_5704delGAGA (p.Glu1901Argfs*18), c.9154_9155delCT (p.Cys3053Serfs*9), c.9460delG (p.Val3154*), c.9379C>T (p.Gln3127*), c.12115C>T (p.Gln4039*), c.1468dupA (p.Thr490Asnfs*15), c.10825C>T (p.Arg3609*) and c.3902C>A (p.Ser1301*). Among these, c.9154_ 9155delCT, c.9460delG, c.9379C>T, and c.1468dupA were unreported previously. Based on the standards and guidelines of American College of Medical Genetics and Genomics, the c.9379C>T and c.12115C>T variants of the ALMS1 gene were predicted to be likely pathogenic (PVS1+PM2), whilst the other 10 variants were predicted to be pathogenic (PVS1+ PM2+ PP3+PP4). CONCLUSION ALMS1 variants probably underlay the Alström syndrome in the 7 patients, and genetic testing can provide a basis for the clinical diagnosis of this syndrome. The discovery of four novel variants has expanded the mutational spectrum of Alström syndrome.
Alstrom Syndrome/genetics* ; Cell Cycle Proteins/genetics* ; Humans ; Mutation ; Pedigree ; Whole Exome Sequencing

OBJECTIVE: To explore the clinical characteristics and genetic etiology of a Chinese pedigree affected with Alström syndrome. METHODS: A pedigree with 5 members affected with Alström syndrome who had visited the First Affiliated Hospital of Zhengzhou University in February 2021 was selected as the study subject. Clinical data of the pedigree were collected, and peripheral venous blood samples were collected for the extraction of genomic DNA. Genetic testing was carried out for the eldest daughter and third son through whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing and bioinformatic analysis. RESULTS: The eldest daughter (14 years old) and the third son (11 years old) both had congenital nystagmus, amblyopia, growth retardation and type 2 diabetes. WES revealed that both had harbored homozygous c.3538A>T (p.Lys1180*) variant of the ALMS1 gene. Sanger sequencing confirmed that the father, mother, and second daughter were all heterozygous carriers. Based on the Guidelines for Genetic Variation and the Technical Standards for Interpretation and Reporting of Primary Copy Number Variations, the variant was predicted as pathogenic (PVS1+PM2_Supporting+PP4). CONCLUSION The homozygous c.3538A>T (p.Lys1180*) variant of the ALSM1 gene probably underlay the Alström syndrome in this pedigree, which has provided a reference for the clinical treatment.
Adolescent ; Child ; Humans ; Alstrom Syndrome/genetics* ; Diabetes Mellitus, Type 2 ; DNA Copy Number Variations ; East Asian People ; Pedigree ; Male ; Female

BACKGROUND: Alstrom syndrome and Bardet-Biedl syndrome are autosomal recessively inherited ciliopathies with common characteristics of obesity, diabetes, and blindness. Alstrom syndrome is caused by a mutation in the ALMS1 gene, and Bardet-Biedl syndrome is caused by mutations in BBS1-16 genes. Herein we report genetically confirmed cases of Alstrom syndrome and Bardet-Biedl syndrome in Korea using whole exome sequencing. METHODS: Exome capture was done using SureSelect Human All Exon Kit V4+UTRs (Agilent Technologies). HiSeq2000 system (Illumina) was used for massive parallel sequencing. Sanger sequencing was used for genotype confirmation and familial cosegregation analysis. RESULTS: A 21-year old Korean woman was clinically diagnosed with Alstrom syndrome. She had diabetes, blindness, obesity, severe insulin resistance, and hearing loss. Whole exome sequencing revealed a nonsense mutation in exon 10 of ALMS1 (c.8776C>T, p.R2926X) and a seven base-pair deletion resulting in frameshift mutation in exon 8 (c.6410_6416del, p.2137_2139del). A 24-year-old Korean man had Bardet-Biedl syndrome with diabetes, blindness, obesity, and a history of polydactyly. Whole exome sequencing revealed a nonsynonymous mutation in exon 11 of the BBS1 gene (c.1061A>G, p.E354G) and mutation at the normal splicing recognition site of exon 7 of the BBS1 gene (c.519-1G>T). CONCLUSION: We found novel compound heterozygous mutations of Alstrom syndrome and Bardet-Biedl syndrome using whole exome sequencing. The whole exome sequencing successfully identified novel genetic variants of ciliopathy-associated diabetes.
Alstrom Syndrome ; Bardet-Biedl Syndrome ; Blindness ; Codon, Nonsense ; Diabetes Mellitus ; Exome* ; Exons ; Female ; Frameshift Mutation ; Genotype ; Hearing Loss ; Humans ; Insulin Resistance ; Korea ; Obesity ; Obesity, Morbid ; Polydactyly ; Young Adult

Obesity has become a common healthcare problem worldwide. Cilia are tiny hair-like organelles on the cell surface that are generated and anchored by the basal body. Non-motile primary cilia have been considered to be evolutionary rudiments until a few decades, but they are now considered as important signaling organelles because many receptors, channels, and signaling molecules are highly expressed in primary cilia. A potential role of primary cilia in metabolic regulation and body weight maintenance has been suspected based on rare genetic disorders termed as ciliopathy, such as Bardet-Biedl syndrome and Alström syndrome, which manifest as obesity. Recent studies have demonstrated involvement of cilia-related cellular signaling pathways in transducing metabolic information in hypothalamic neurons and in determining cellular fate during adipose tissue development. In this review, we summarize the current knowledge about cilia and cilia-associated signaling pathways in the regulation of body metabolism.
Adipose Tissue ; Alstrom Syndrome ; Bardet-Biedl Syndrome ; Basal Bodies ; Body Weight Maintenance ; Cilia* ; Delivery of Health Care ; Energy Metabolism* ; Hedgehogs ; Metabolism ; Neurons ; Obesity ; Organelles ; Wnt Signaling Pathway

The Alstrom syndrome is inherited autosomal recessive disorder, characterized by obesity, diabetes mellitus, pigmentary retinal degeneration, normal intelligence, sensorineural hearing loss, baldness, acanthosis nigricans, male hypogonadism, hyperuricemia and hypertriglyceridemia. There is no reported case of Alstrom syndrome in Korea yet. We experienced a 29-year-old female patient with clinical characteristics similar to Alstrom syndrome who was admitted due to poorly controlled diabetes mellitus and diabetic retinopathy with hemorrhage. We report this case with the review of literatures.
Acanthosis Nigricans ; Adult ; Alopecia ; Alstrom Syndrome* ; Diabetes Mellitus ; Diabetic Retinopathy ; Female ; Hearing Loss, Sensorineural ; Hemorrhage ; Humans ; Hypertriglyceridemia ; Hyperuricemia ; Hypogonadism ; Intelligence ; Korea ; Male ; Obesity ; Retinal Degeneration