To trust or not to trust an idiosyncratic mitochondrial data set.

(2000) Epigenotype-phenotype correlations in Beckwith-Wiedemann syndrome. J Med Ge-net 37:921–926 Fitzpatrick GV, Soloway PD, Higgins MJ (2002) Regional loss of imprinting and growth deficiency in mice with a targeted deletion of KvDMR1. (2001) Analysis of the methylation status of the KCNQ1OT and H19 genes in leukocyte DNA for the diagnosis and prognosis of Beckwith-Wiedemann syndrome. (1999) Loss of imprinting of a paternally expressed transcript, with antisense orientation to KvLQT1, occurs frequently in Beckwith-Wiedemann syndrome and is independent of insulin-like growth factor II imprinting. (2000) Study of DNA-methylation patterns at chromosome 15q11-q13 in children born after ICSI reveals no imprinting defects. (1999) LIT1, an imprinted antisense RNA in the human KvLQT1 locus identified by screening for differentially expressed transcripts using monochromosomal hybrids. (2001) Perinatal outcome of pregnancy after GnRH antagonist (ganirelix) treatment during ovarian stimulation for conventional IVF or ICSI: a preliminary report. (2003) Another case of imprinting defect in a girl with Angelman syndrome who was conceived by intracytoplasmic sperm injection. A maternally methylated CpG island in KvLQT1 is associated with an antisense paternal transcript and loss of imprinting in Beckwith-Wiedemann syndrome. (2001) Tumor development in the Beckwith-Wiedemann syndrome is associated with a variety of constitutional molecular 11p15 alterations including imprinting defects of KCNQ1OT1. (2001) Epigenetic change in IGF2R is associated with fetal overgrowth after sheep embryo culture. To the Editor: In a recent report, Silva et al. (2002) provided partial (8.8 kb) information on the mtDNA coding region (within the region 7148–15946, in the numbering of the Cambridge reference sequence [CRS]; Anderson et al. [1981]) in 40 individuals from Brazil. On the basis of the similarity in nucleotide diversity and age estimates of the four founder haplogroups A, B, C, and D, they claimed to have added new evidence for a single early entry of the founder populations into America. However, a site-by-site audit of the data reveals that their sequences are not of high enough quality to justify such statements. The authors failed to realize that a large number of mutations associated with basal branches of the worldwide mtDNA phylogeny (Finnilä et al. 2001; Maca-Meyer et al. 2001; Torroni et al. 2001; Derbeneva et al. 2002; Herrnstadt et al. 2002; Kivisild et al. 2002) were not correctly scored in their data set.