Clinical characterization of individuals with the distal 1q21.1 microdeletion.

TitleClinical characterization of individuals with the distal 1q21.1 microdeletion.
Publication TypeJournal Article
Year of Publication2021
AuthorsEdwards, SD, Schulze, KV, Rosenfeld, JA, Westerfield, LE, Gerard, A, Yuan, B, Grigorenko, EL, Posey, JE, Bi, W, Liu, P
JournalAm J Med Genet A
Date Published2021 05
KeywordsAbnormalities, Multiple, Adolescent, Adult, Child, Child, Preschool, Chromosome Deletion, Chromosomes, Human, Pair 1, Developmental Disabilities, DNA Copy Number Variations, Failure to Thrive, Female, Genetic Counseling, Genetic Testing, Heart Defects, Congenital, Humans, Infant, Intellectual Disability, Male, Megalencephaly, Microcephaly, Pedigree, Seizures, Young Adult

Distal 1q21.1 microdeletions have shown highly variable clinical expressivity and incomplete penetrance, with affected individuals manifesting a broad spectrum of nonspecific features. The goals of this study were to better describe the phenotypic spectrum of patients with distal 1q21.1 microdeletions and to compare the clinical features among affected individuals. We performed a retrospective chart review of 47 individuals with distal 1q21.1 microdeletions tested at a large clinical genetic testing laboratory, with most patients being clinically evaluated in the same children's hospital. Health information such as growth charts, results of imaging studies, developmental history, and progress notes were collected. Statistical analysis was performed using Fisher's exact test to compare clinical features among study subjects. Common features in our cohort include microcephaly (51.2%), seizures (29.8%), developmental delay (74.5%), failure to thrive (FTT) (68.1%), dysmorphic features (63.8%), and a variety of congenital anomalies such as cardiac abnormalities (23.4%) and genitourinary abnormalities (19.1%). Compared to prior literature, we found that seizures, brain anomalies, and FTT were more prevalent among our study cohort. Females were more likely than males to have microcephaly (p = 0.0199) and cardiac abnormalities (p = 0.0018). Based on existing genome-wide clinical testing results, at least a quarter of the cohort had additional genetic findings that may impact the phenotype of the individual. Our study represents the largest cohort of distal 1q21.1 microdeletion carriers available in the literature thus far, and it further illustrates the wide spectrum of clinical manifestations among symptomatic individuals. These results may allow for improved genetic counseling and management of affected individuals. Future studies may help to elucidate the underlying molecular mechanisms impacting the phenotypic variability observed with this microdeletion.

Alternate JournalAm J Med Genet A
PubMed ID33576134
Grant ListK08 HG008986 / HG / NHGRI NIH HHS / United States

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