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Neurocognitive assessment and DNA sequencing expand the phenotype and genotype spectrum of Alström syndrome
Author(s) -
Dassie Francesca,
Lorusso Riccardina,
BenavidesVarela Silvia,
Milan Gabriella,
Favaretto Francesca,
Callus Edward,
Cagnin Stefano,
Reggiani Francesco,
Minervini Giovanni,
Tosatto Silvio,
Vettor Roberto,
Semenza Carlo,
Maffei Pietro
Publication year - 2021
Publication title -
american journal of medical genetics part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.064
H-Index - 112
eISSN - 1552-4833
pISSN - 1552-4825
DOI - 10.1002/ajmg.a.62029
Subject(s) - neurocognitive , medicine , working memory , neuropsychology , audiology , phenotype , cognition , genetics , psychology , psychiatry , biology , gene
Alström syndrome (OMIM#203800) is an ultra‐rare autosomal recessive monogenic disease presenting pathogenic variants in ALMS1 (chromosome 2p13). It is characterized by early onset of blindness, hearing loss and systemic comorbidities, with delayed development without cognitive impairment. We aimed to investigate the cognitive functions and describe new pathogenic variants in Alström syndrome patients. Nineteen patients (13 adults, 6 children) underwent a thorough clinical, genetic, laboratory, instrumental, and neurocognitive assessment. Six new pathogenic variants in ALMS1 including the first described in exon 6 were identified. Four patients displayed a “mild phenotype” characterized by slow disease onset or absence of complications, including childhood obesity and association with at least one pathogenic variant in exon 5 or 6. At neurocognitive testing, a significant proportion of patients had deficits in three neurocognitive domains: similarities, phonological memory, and apraxia. In particular, 53% of patients showed difficulties in the auditory working memory test. We found ideomotor and buccofacial apraxia in 74% of patients. “Mild phenotype” patients performed better on auditory working memory and ideomotor apraxia test than “typical phenotype” ones (91.9 + 16.3% vs. 41.7 + 34.5% of correct answers, Z = 64.5, p < .01 and 92.5 + 9.6 vs. 61.7 + 26.3, Z = 61, p < .05, respectively). Deficits in auditory working memory, ideomotor, and buccofacial apraxia were found in these patients and fewer neuropsychological deficits were found in the “mild” phenotype group. Furthermore, in the “mild” phenotype group, it was found that all pathogenic variants are localized before exon 8.