Breakpoint mapping and haplotype analysis of translocation t(1;12)(q43;q21.1) in two apparently independent families with vascular phenotypes

TY - JOUR

T1 - Breakpoint mapping and haplotype analysis of translocation t(1;12)(q43;q21.1) in two apparently independent families with vascular phenotypes

AU - Luukkonen, Tiia Maria

AU - Mehrjouy, Mana M

AU - Pöyhönen, Minna

AU - Anttonen, Anna-Kaisa

AU - Lahermo, Päivi

AU - Ellonen, Pekka

AU - Paulin, Lars

AU - Tommerup, Niels

AU - Palotie, Aarno

AU - Varilo, Teppo

N1 - © 2017 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals, Inc.

PY - 2018/1

Y1 - 2018/1

N2 - BACKGROUND: The risk of serious congenital anomaly for de novo balanced translocations is estimated to be at least 6%. We identified two apparently independent families with a balanced t(1;12)(q43;q21.1) as an outcome of a "Systematic Survey of Balanced Chromosomal Rearrangements in Finns." In the first family, carriers (n = 6) manifest with learning problems in childhood, and later with unexplained neurological symptoms (chronic headache, balance problems, tremor, fatigue) and cerebral infarctions in their 50s. In the second family, two carriers suffer from tetralogy of Fallot, one from transient ischemic attack and one from migraine. The translocation cosegregates with these vascular phenotypes and neurological symptoms.METHODS AND RESULTS: We narrowed down the breakpoint regions using mate pair sequencing. We observed conserved haplotypes around the breakpoints, pointing out that this translocation has arisen only once. The chromosome 1 breakpoint truncates a CHRM3 processed transcript, and is flanked by the 5' end of CHRM3 and the 3' end of RYR2. TRHDE, KCNC2, and ATXN7L3B flank the chromosome 12 breakpoint.CONCLUSIONS: This study demonstrates a balanced t(1;12)(q43;q21.1) with conserved haplotypes on the derived chromosomes. The translocation seems to result in vascular phenotype, with or without neurological symptoms, in at least two families. We suggest that the translocation influences the positional expression of CHRM3, RYR2, TRHDE, KCNC2, and/or ATXN7L3B.

AB - BACKGROUND: The risk of serious congenital anomaly for de novo balanced translocations is estimated to be at least 6%. We identified two apparently independent families with a balanced t(1;12)(q43;q21.1) as an outcome of a "Systematic Survey of Balanced Chromosomal Rearrangements in Finns." In the first family, carriers (n = 6) manifest with learning problems in childhood, and later with unexplained neurological symptoms (chronic headache, balance problems, tremor, fatigue) and cerebral infarctions in their 50s. In the second family, two carriers suffer from tetralogy of Fallot, one from transient ischemic attack and one from migraine. The translocation cosegregates with these vascular phenotypes and neurological symptoms.METHODS AND RESULTS: We narrowed down the breakpoint regions using mate pair sequencing. We observed conserved haplotypes around the breakpoints, pointing out that this translocation has arisen only once. The chromosome 1 breakpoint truncates a CHRM3 processed transcript, and is flanked by the 5' end of CHRM3 and the 3' end of RYR2. TRHDE, KCNC2, and ATXN7L3B flank the chromosome 12 breakpoint.CONCLUSIONS: This study demonstrates a balanced t(1;12)(q43;q21.1) with conserved haplotypes on the derived chromosomes. The translocation seems to result in vascular phenotype, with or without neurological symptoms, in at least two families. We suggest that the translocation influences the positional expression of CHRM3, RYR2, TRHDE, KCNC2, and/or ATXN7L3B.

U2 - 10.1002/mgg3.346

DO - 10.1002/mgg3.346

M3 - Journal article

C2 - 29168350

SN - 2324-9269

VL - 6

SP - 56

EP - 68

JO - Molecular genetics & genomic medicine

JF - Molecular genetics & genomic medicine

IS - 1

ER -