Faculty Collaboration Database

Expanding the clinical phenotype of individuals with a 3-bp in-frame deletion of the NF1 gene (c.2970_2972del): an update of genotype-phenotype correlation. Genet Med 2019 Apr;21(4):867-876

Date

09/08/2018

Pubmed ID

30190611

Pubmed Central ID

PMC6752285

DOI

10.1038/s41436-018-0269-0

Scopus ID

2-s2.0-85053443613 (requires institutional sign-in at Scopus site)   61 Citations

Abstract

PURPOSE: Neurofibromatosis type 1 (NF1) is characterized by a highly variable clinical presentation, but almost all NF1-affected adults present with cutaneous and/or subcutaneous neurofibromas. Exceptions are individuals heterozygous for the NF1 in-frame deletion, c.2970_2972del (p.Met992del), associated with a mild phenotype without any externally visible tumors.

METHODS: A total of 135 individuals from 103 unrelated families, all carrying the constitutional NF1 p.Met992del pathogenic variant and clinically assessed using the same standardized phenotypic checklist form, were included in this study.

RESULTS: None of the individuals had externally visible plexiform or histopathologically confirmed cutaneous or subcutaneous neurofibromas. We did not identify any complications, such as symptomatic optic pathway gliomas (OPGs) or symptomatic spinal neurofibromas; however, 4.8% of individuals had nonoptic brain tumors, mostly low-grade and asymptomatic, and 38.8% had cognitive impairment/learning disabilities. In an individual with the NF1 constitutional c.2970_2972del and three astrocytomas, we provided proof that all were NF1-associated tumors given loss of heterozygosity at three intragenic NF1 microsatellite markers and c.2970_2972del.

CONCLUSION: We demonstrate that individuals with the NF1 p.Met992del pathogenic variant have a mild NF1 phenotype lacking clinically suspected plexiform, cutaneous, or subcutaneous neurofibromas. However, learning difficulties are clearly part of the phenotypic presentation in these individuals and will require specialized care.

Author List

Koczkowska M, Callens T, Gomes A, Sharp A, Chen Y, Hicks AD, Aylsworth AS, Azizi AA, Basel DG, Bellus G, Bird LM, Blazo MA, Burke LW, Cannon A, Collins F, DeFilippo C, Denayer E, Digilio MC, Dills SK, Dosa L, Greenwood RS, Griffis C, Gupta P, Hachen RK, Hernández-Chico C, Janssens S, Jones KJ, Jordan JT, Kannu P, Korf BR, Lewis AM, Listernick RH, Lonardo F, Mahoney MJ, Ojeda MM, McDonald MT, McDougall C, Mendelsohn N, Miller DT, Mori M, Oostenbrink R, Perreault S, Pierpont ME, Piscopo C, Pond DA, Randolph LM, Rauen KA, Rednam S, Rutledge SL, Saletti V, Schaefer GB, Schorry EK, Scott DA, Shugar A, Siqveland E, Starr LJ, Syed A, Trapane PL, Ullrich NJ, Wakefield EG, Walsh LE, Wangler MF, Zackai E, Claes KBM, Wimmer K, van Minkelen R, De Luca A, Martin Y, Legius E, Messiaen LM

Author

Donald Basel MD Chief, Professor in the Pediatrics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adolescent
Adult
Child
Child, Preschool
Female
Genetic Association Studies
Genetic Predisposition to Disease
Heterozygote
Humans
Infant
Male
Mutation, Missense
Neurofibroma, Plexiform
Neurofibromatosis 1
Neurofibromin 1
Sequence Deletion
Young Adult