Double aneuploidy (48,XXY,+21) of maternal origin in a child born to a 13-year-old mother: evaluation of the maternal folate metabolism.
The occurrence of non-mosaic double trisomy is exceptional in newborns. In this paper, a 48,XXY,+21 child, the parental origin of the extra chromosomes and the evaluation of the maternal folate metabolism are presented. The infant was born to a 13-year-old mother and presented with the typical clinical features of Down syndrome (DS). The origin of the additional chromosomes was maternal and most likely resulted from errors during the first meiotic division. Molecular analysis of 12 genetic polymorphisms involved in the folate metabolism revealed that the mother is heterozygous for the MTHFR C677T and TC2 A67G polymorphisms, and homozygous for the mutant MTRR A66G polymorphism. The maternal homocysteine concentration was 4.7 miromol/L, a value close to the one considered as a risk factor for DS in our previous study. Plasma methylmalonic acid and serum folate concentrations were 0.17 micromol/L and 18.4 ng/mL, respectively. It is possible that the presence of allelic variants for the folate metabolism and Hey concentration might have favored errors in chromosomal disjunction during gametogenesis in this young mother. To our knowledge, this is the first patient with non-mosaic Down-Klinefelter born to a teenage mother, resulting from a rare fertilization event combining an abnormal 25,XX,+21 oocyte and a 23,Y spermatozoon.
Unidade de Pesquisa em Genética e Biologia Molecular, Departamento de Biologia Molecular, Faculdade de Medicina de São José do Rio Preto--FAMERP, São José do Rio Preto, SP, Brasil.
J M
JM
Biselli
F B
FB
Machado
B L
BL
Zampieri
A F
AF
Alves da Silva
E M
EM
Goloni-Bertollo
R
R
Haddad
M N
MN
Eberlin
H
H
Vannucchi
V M
VM
Carvalho
E
E
Medina-Acosta
E C
EC
Pavarino-Bertelli
D000293:Adolescent; D000483:Alleles; D000782:Aneuploidy; D001938:Brazil; D041321:Chromosomes, Human, X / Q000235:genetics*; D041322:Chromosomes, Human, Y / Q000235:genetics*; D004252:DNA Mutational Analysis; D004314:Down Syndrome / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D005287:Ferredoxin-NADP Reductase / Q000235:genetics*; D005492:Folic Acid / Q000097:blood*; D006580:Genetic Carrier Screening; D005838:Genotype; D006330:Heart Defects, Congenital / Q000175:diagnosis / Q000235:genetics; D006710:Homocysteine / Q000097:blood; D006720:Homozygote; D006801:Humans; D007223:Infant; D007713:Klinefelter Syndrome / Q000175:diagnosis / Q000235:genetics*; D008297:Male; D008540:Meiosis; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D008764:Methylmalonic Acid / Q000097:blood; D009630:Nondisjunction, Genetic / Q000235:genetics; D011110:Polymorphism, Genetic / Q000235:genetics*; D011247:Pregnancy; D011253:Pregnancy in Adolescence / Q000235:genetics*; D012729:Sex Chromosome Aberrations; D014314:Trisomy
D006710:Homocysteine; D008764:Methylmalonic Acid; D005492:Folic Acid; C111241:methionine synthase reductase; D005287:Ferredoxin-NADP Reductase; D042965:Methylenetetrahydrofolate Reductase (NADPH2)