ICF syndrome in a girl with DNA hypomethylation but without detectable DNMT3B mutation.
A 3-year-old girl with phenotypic and cytogenetic manifestations of the ICF syndrome and DNA hypomethylation but without DNMT3B gene mutation is described. At age 3 months, she had an apneic spell that left her with spastic paraplegia and severe mental retardation. At age 8 months, she suffered meningococcal meningitis and sepsis. When seen by us at age 3 years with virilization, she had a cleft plate, macroglossia, and an atrial septal defect. An adenoma was surgically removed from the right adrenal cortex. Her serum immunoglobulin levels were normal except IgA at the low normal border. Her lymphocytes showed paracentromeric stretching of chromosomes 1 and 16 in 7% of metaphases, and multiradial figures involving these chromosomes in 1% of cells. Hypomethylation of classical satellite 2 DNA was observed with BstBI digestion, but in a lesser degree than those in the individuals with proven DNMT3B mutations. No mutation was found in the coding and promoter regions of the gene. Several alternative interpretations were considered to explain the low frequencies of chromosomal instabilities and the lower degree of DNA hypomethylation, and undetected DNA3B mutations. A mutation may be present in the gene but undetected, present in other DNA methyltransferases (DNMT) genes or in a DNMT-associated protein gene.
Kubota
Takeo
T
Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, Kodaira, Japan. takeot@yamanashi.ac.jp
Furuumi
Hiroyasu
H
Kamoda
Tomohiro
T
Iwasaki
Nobuaki
N
Tobita
Naomi
N
Fujiwara
Nobuko
N
Goto
Yu-Ichi
Y
Matsui
Akira
A
Sasaki
Hiroyuki
H
Kajii
Tadashi
T
D000015:Abnormalities, Multiple / Q000235:genetics*; D002503:Centromere / Q000235:genetics / Q000473:pathology; D002675:Child, Preschool; D043171:Chromosomal Instability / Q000235:genetics*; D019465:Craniofacial Abnormalities / Q000235:genetics; D019175:DNA Methylation; D004252:DNA Mutational Analysis; D017931:DNA Primers; D004276:DNA, Satellite / Q000235:genetics; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007154:Immune System Diseases / Q000151:congenital / Q000235:genetics*; D008607:Intellectual Disability / Q000235:genetics*
D017931:DNA Primers; D004276:DNA, Satellite