Objective To assess the impact of breast feeding on the risk of obesity and risk of being overweight in children at the time of entry to school. Design Cross sectional survey Setting Bavaria, southern Germany. Methods Routine data were collected on the height and weight of 134 577 children participating in the obligatory health examination at the time of school entry in Bavaria. In a subsample of 13 345 children, early feeding, diet, and lifestyle factors were assessed using responses to a questionnaire completed by parents. Subjects 9357 children aged 5 and 6 who had German nationality. Main outcome measures Being overweight was defined as having a body mass index above the 90th centile and obesity was defined as body mass index above the 97th centile of all enrolled German children. Exclusive breast feeding was defined as the child being fed no food other than breast milk. Results The prevalence of obesity in children who had never been breast fed was 4.5% as compared with 2.8% in breastfed children. A clear dose-response effect was identified for the duration of breast feeding on the prevalence of obesity: the prevalence was 3.8% for 2 months of exclusive breast feeding, 2.3% for 3-5 months, 1.7% for 6-12 months, and 0.8% for more than 12 months. Similar relations were found with the prevalence of being overweight. The protective effect of breast feeding was not attributable to differences in social class or lifestyle. After adjusting for potential confounding factors, breast feeding remained a significant protective factor against the development of obesity (odds ratio 0.75, 95% CI 0.57 to 0.98) and being overweight (0.79, 0.68 to 0.93). Conclusions In industrialised countries promoting prolonged breast feeding may help decrease the prevalence of obesity in childhood. Since obese children have a high risk of becoming obese adults, such preventive measures may eventually result in a reduction in the prevalence of cardiovascular diseases and other diseases related to obesity.

Agenesis of the corpus callosum (ACC) is among the most frequent human brain malformations with an incidence of 0.5–70 in 10,000. It is a heterogeneous condition, for which several different genetic causes are known, for example, ACC as part of monogenic syndromes or complex chromosomal rearrangements. We systematically evaluated the data of 172 patients with documented corpus callosum abnormalities in the records, and 23 patients with chromosomal rearrangements known to be associated with corpus callosum changes. All available neuroimaging data, including CT and MRI, were re-evaluated following a standardized protocol. Whenever feasible chromosome and subtelomere analyses as well as molecular genetic testing were performed in patients with disorders of the corpus callosum in order to identify a genetic diagnosis. Our results showed that 41 patients with complete absence (agenesis of the corpus callosum—ACC) or partial absence (dysgenesis of the corpus callosum—DCC) were identified. Out of these 28 had ACC, 13 had DCC. In 11 of the 28 patients with ACC, the following diagnoses could be established: Mowat–Wilson syndrome (n = 2), Walker–Warburg syndrome (n = 1), oro-facial-digital syndrome type 1 (n = 1), and chromosomal rearrangements (n = 7), including a patient with an apparently balanced reciprocal translocation, which led to the disruption and a predicted loss of function in the FOXG1B gene. The cause of the ACC in 17 patients remained unclear. In 2 of the 13 patients with DCC, unbalanced chromosomal rearrangements could be detected (n = 2), while the cause of DCC in 11 patients remained unclear. In our series of cases a variety of genetic causes of disorders of the corpus callosum were identified with cytogenetic anomalies representing the most common underlying etiology.

We have investigated the chromosome abnormalities in a female patient exhibiting a severe cognitive disability associated with complete agenesis of the corpus callosum and microcephaly. The patient carries a balanced de novo translocation t(2;14)(p22;q12), together with a neighbouring 720 kb inversion in chromosome 14q12. By combined fluorescence in situ hybridisation and Southern hybridisation, the distal inversion breakpoint on chromosome 14 was mapped to a region harbouring genes and ESTs derived predominantly from brain tissue. RT-PCR studies indicated that these transcripts comprise the 3' ends of novel splice variants of the winged helix transcription factor FOXG1B (also referred to in previous studies as FOXG1A and FOXG1C, as well as Brain Factor 1), the mouse orthologue of which is essential for normal development of the telencephalon. Analysis of these novel FOXG1B transcripts indicated that they are all disrupted by the breakpoint in the patient. Moreover, we have identified novel orthologous Foxg1 transcripts in the mouse and other vertebrates, which validates the functional importance of these variants and provides a direct genetic link between the patient phenotype and that of the heterozygous Foxg1 knockout mice. These results, together with previously published studies on patients with similar disorders and proximal 14q deletions, strongly suggest that several disorders associated with malformations of the human brain may be directly caused by mutations or alterations in the FOXG1B gene.

Interstitial deletions or apparently balanced translocations involving bands 1p31 and 1p32 in the short arm of chromosome 1 are rarely described chromosomal imbalances. To our knowledge, there have been six cases documented to date. Five of these cases, where the NFIA gene is involved, show complex central nervous system malformations and in some cases urinary tract defects. We report another case of a microdeletion with involvement of the NFIA gene in the short arm of chromosome 1 (del(1)(p31.3p32.2)) with, amongst other features, hypoplasia of the corpus callosum, ventriculomegaly, and dysmorphic features. A microdeletion 1p31.3p32.2 which includes the NFIA gene is associated with hypoplasia of the corpus callosum, ventriculomegaly, and dysmorphic features.

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