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CARPHOLOGY by A Fo Ben

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Don’t you hate it when …

… you wait for a paper on genome wide association studies (GWAS) in schizophrenia and three come at once? Schizophrenia is perhaps 80% inherited but phenotyping is challenging and its major genes remain elusive.1 A pan-European study (n = 3322) of schizophrenia using GWAS reported important MHC region variants, strongly supporting a polygenic basis and explaining at least 30% of the liability. Intriguingly, schizophrenia’s genetic data are substantially shared with bipolar disorder.2 A meta-analysis of European ancestry people from three large datasets (8008 cases, 19 077 controls) identified an important linkage disequilibrium on chromosome 6p22.1 (p = 9.54×10−9); seven single nucleotide polymorphisms were significantly associated.3 The Wellcome Trust Case Control Consortium GWAS data for bipolar disorder were re-examined asking which of seven subtypes had the most independent associations. The answer: schizoaffective disorder, bipolar type.

1doi:10.1038/nature08192; 2doi:10.1038/nature08185; 3Br J Psychiatry 2009;195:23–9.

White spots in Icelandic migraine

In a prospective Icelandic cohort (n = 4689), 7.7% experienced migraine with aura in “midlife”. Infarct-like lesions on MRI up to 23 years later were common (39% of men and 25% of women) and the excess of these in migraineurs was mainly from cerebellar lesions (23% women and 19% men). On closer analysis, this excess was solely in women (men OR 1.0; 95% CI 0.6 to 1.8; women OR 1.9; 95% CI 1.4 to 2.6; p = 0.04) and independent of vascular risk factors in mid or later life. The hyperintensities were not typically ischaemic and may not represent infarcts at all. Despite the established association between migraine and ischaemic stroke, the clinical implications are unclear.

JAMA 2009;301:2563–70.

Older people drive safer on the left

Most neurologists, despite an interest in handedness, would assume traffic safety to be uninfluenced by traffic directionality. However, a German group hypothesize that, with age, left-sided directionality becomes safer than right-sided. Diverging hemispheric asymmetry of attentional functions combined with age acquired brain lesions (especially vascular) mean more elderly drivers have attention deficits for the left than for the right half of their environment. Yet right-sided traffic directionality means drivers and pedestrians each need more attention to the left than the right. A Fo Ben recommends looking both ways before crossing a road, whatever your age.

Med Hypotheses 2009;73:20–3.

UK tonsils still prion free

Concerns that Britons exposed to bovine spongiform encephalopathy may still be incubating variant prion protein in their lymphoreticular system seem somewhat allayed by a huge prevalence study of 63 007 anonymous UK tonsils. PrPCJD was absent from all specimens. Among the birth cohort 1961–1985 from which most variant CJD cases arose, the latest prevalence estimate becomes 0 to 289 per million. While still consistent with the previous appendix derived estimate, it gives some reassurance to those whose diet contained British cattle derived products in the 1980s.

BMJ 2009;338:1316.

Antipsychotics and hypoglycaemia

When assessing an unconscious patient on a psychiatric ward, the mnemonic ABC (airway, breathing, circulation) must be followed by DEFG (don’t ever forget glucose). A Japanese group reports three cases where second generation antipsychotic agents (quetiapine, risperidone and olanzapine) induced hypoglycaemia in non-diabetic schizophrenic patients. None became unconscious but the neuroglycopenic adrenergic symptoms of irritability and anxiety are easily overlooked in psychotic patients.

BMJ 2009;338:1387–8.

This may have been tricky getting through ethics…

If breaking bad news is a skill, then carefully explaining inconclusive results must be an art form. Preparation (both practically for the clinician and psychologically for the recipient) is key. American researchers randomised 162 asymptomatic people who had a relative with Alzheimer’s either to be told or not be told their APOE status. They must have expected upset because anxiety, depression and test related distress (measured up to 1 year) were primary outcomes. Although the two groups did not behave differently, those with high levels of depression and anxiety before testing showed more emotional difficulties after disclosure.

N Engl J Med 2009;361:245–54.

You know what they say about men with big feet?

They need big socks. A Fo Ben, making the neurology/urology mistake beloved of hospital switchboards (it’s heads, not tails) wondered if anyone publishes in the “does shoe size predict penis length?” field. The answer is “yes”, our top men are working on it but “no”, there is no correlation. 104 men had median stretched (flaccid) penis length of 13 cm (range 6–18 cm); their shoe sizes ranged from 5.5 to 13, but you’re less interested in that. The authors state that their method had several advantages, not least that an independent researcher measured the men. You could scarcely believe it but apparently men overestimate their penis length when asked to self-measure.

BJU Int 2002;90:586–7.

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