TY - JOUR
T1 - The Phenotypic Spectrum of PNKP-Associated Disease and the Absence of Immunodeficiency and Cancer Predisposition in a Dutch Cohort
AU - Garrelfs, Mark R
AU - Takada, Sanami
AU - Kamsteeg, Erik-Jan
AU - Pegge, Sjoert
AU - Mancini, Grazia
AU - Engelen, Marc
AU - van de Warrenburg, Bart
AU - Rennings, Alexander
AU - van Gaalen, Judith
AU - Peters, Ivo
AU - Weemaes, Corry
AU - van der Burg, Mirjam
AU - Willemsen, Michèl A
N1 - Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.
PY - 2020/12/1
Y1 - 2020/12/1
N2 - BACKGROUND: We aimed to expand the number of currently known pathogenic PNKP mutations, to study the phenotypic spectrum, including radiological characteristics and genotype-phenotype correlations, and to assess whether immunodeficiency and increased cancer risk are part of the DNA repair disorder caused by mutations in the PNKP gene.METHODS: We evaluated nine patients with PNKP mutations. A neurological history and examination was obtained. All patients had undergone neuroimaging and genetic testing as part of the prior diagnostic process. Laboratory measurements included potential biomarkers, and, in the context of a DNA repair disorder, we performed a detailed immunologic evaluation, including B cell repertoire analysis.RESULTS: We identified three new mutations in the PNKP gene and confirm the phenotypic spectrum of PNKP-associated disease, ranging from microcephaly, seizures, and developmental delay to ataxia with oculomotor apraxia type 4. Irrespective of the phenotype, alpha-fetoprotein is a biochemical marker and increases with age and progression of the disease. On neuroimaging, (progressive) cerebellar atrophy was a universal feature. No clinical signs of immunodeficiency were present, and immunologic assessment was unremarkable. One patient developed cancer, but this was attributed to a concurrent von Hippel-Lindau mutation.CONCLUSIONS: Immunodeficiency and cancer predisposition do not appear to be part of PNKP-associated disease, contrasting many other DNA repair disorders. Furthermore, our study illustrates that the previously described syndromes microcephaly, seizures, and developmental delay, and ataxia with oculomotor apraxia type 4, represent the extremes of an overlapping spectrum of disease. Cerebellar atrophy and elevated serum alpha-fetoprotein levels are early diagnostic findings across the entire phenotypical spectrum.
AB - BACKGROUND: We aimed to expand the number of currently known pathogenic PNKP mutations, to study the phenotypic spectrum, including radiological characteristics and genotype-phenotype correlations, and to assess whether immunodeficiency and increased cancer risk are part of the DNA repair disorder caused by mutations in the PNKP gene.METHODS: We evaluated nine patients with PNKP mutations. A neurological history and examination was obtained. All patients had undergone neuroimaging and genetic testing as part of the prior diagnostic process. Laboratory measurements included potential biomarkers, and, in the context of a DNA repair disorder, we performed a detailed immunologic evaluation, including B cell repertoire analysis.RESULTS: We identified three new mutations in the PNKP gene and confirm the phenotypic spectrum of PNKP-associated disease, ranging from microcephaly, seizures, and developmental delay to ataxia with oculomotor apraxia type 4. Irrespective of the phenotype, alpha-fetoprotein is a biochemical marker and increases with age and progression of the disease. On neuroimaging, (progressive) cerebellar atrophy was a universal feature. No clinical signs of immunodeficiency were present, and immunologic assessment was unremarkable. One patient developed cancer, but this was attributed to a concurrent von Hippel-Lindau mutation.CONCLUSIONS: Immunodeficiency and cancer predisposition do not appear to be part of PNKP-associated disease, contrasting many other DNA repair disorders. Furthermore, our study illustrates that the previously described syndromes microcephaly, seizures, and developmental delay, and ataxia with oculomotor apraxia type 4, represent the extremes of an overlapping spectrum of disease. Cerebellar atrophy and elevated serum alpha-fetoprotein levels are early diagnostic findings across the entire phenotypical spectrum.
KW - AOA4 ataxia with oculomotor apraxia type 4
KW - DNA repair
KW - Immunodeficiency
KW - MCSZ microcephaly, seizures and developmental delay
KW - PNKP Polynucleotide kinase 3′-phosphatase
UR - http://www.scopus.com/inward/record.url?scp=85091843021&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.pediatrneurol.2020.07.014
DO - https://doi.org/10.1016/j.pediatrneurol.2020.07.014
M3 - Article
C2 - 32980744
SN - 0887-8994
VL - 113
SP - 26
EP - 32
JO - Pediatric neurology
JF - Pediatric neurology
ER -