Inferences on the inheritance of congenital anomalies from temporal and spatial patterns of occurrence

Most congenital anomalies are believed to result from interactions between genetic and environmental determinants, whose relative importance is not generally established. Temporal and spatial patterns allow inferences on the underlying transmission processes; in particular, it is possible to discriminate between sporadic and nonsporadic genetic factors, and to find evidence for the effects of environmental heterogeneity in time and space. We studied the occurrence of 14 anomalies in 14 registries of Western Europe. Four basic patterns have been identified: (1) Chromosomal abnormalities have uniform incidences and do not show significant geographical variation, in agreement with the expected consequences of randomly scattered nondisjunction events. (2) The homogeneous spatial distributions of three severe malformations (renal agenesis, oesophageal atresia, ano-rectal atresia) are consistent with both the effects of fresh mutation and segregation of detrimental alleles. (3) A decrease of similarity of incidences with distance has been observed for neural tube defects, and this is the expected consequence of isolation by distance on genetically determined traits. (4) For facial clefts, polydactyly, and hypospadias, all postulated processes poorly account for the observed temporal and spatial patterns.     

Genetics and autoantibodies

Autoimmune diseases (ADs) are chronic conditions initiated by the loss of immunological tolerance to self-antigens. The pathogenic hypothesis comprises a complex interaction between genetic, environmental and hormonal factors that interact with an individual over time generating a dysregulation of the immune system leading to disease development. Several polymorphic genes contribute to the development of ADs. Furthermore, age and gender play a major role by influencing hormone levels that can represent the fulcrum unbalancing from susceptibility to protection. Evidences suggest that while all these steps occur, the susceptible individual develops autoantibodies over a long time lapse. Such autoantibody production is genetically determined and finally, their presence seems to determine the clinical presentation of ADs. The genetic predisposition to the developments of autoantibodies and toward the disease process may overlap. The unveiling of these mechanisms could allow not only to treat but also to prevent the development of autoimmune diseases.     

Serum glucose concentration and ACP1 genotype in healthy adult subjects

Acid phosphatase locus 1 (ACP 1 ) or cytosolic low molecular weight protein tyrosine phosphatase is a polymorphic enzyme that can hydrolyze phosphotyrosine-containing peptides of the human insulin receptor and of band 3 protein. High-activity ACP 1 may favor an increase in serum glucose concentration through a depression of insulin action and through inactivation of aldolase, phosphofructokinase, and glyceraldehyde-3-phosphate dehydrogenase induced by dephosphorylation of band 3 protein. In diabetic subjects, we have previously reported lower serum glucose concentration in subjects with low-activity ACP 1 A and AB phenotypes. We have now studied the relationship between serum glucose concentration and ACP 1 genotype in a sample of 137 healthy adult workers of our university. In males, serum glucose concentration is significantly higher in medium-high- than in low-activity ACP 1 genotypes. With advancing age in males, there is a progressive increase in glycemic differential between medium-high- and low-activity ACP 1 genotypes. The data suggest that normal variability of ACP 1 genotype influences serum glucose concentration in normal individuals. Such influence depends on sex and in males becomes more marked with advancing age.     

Colonoscopic screening and follow-up in patients with acromegaly: a multicenter study in Italy

Acromegaly is an infrequent disease attributable to endogenous excess of GH and IGF-I. Human studies have associated the GH-IGF-I axis with the development of colorectal cancer; however, the question of whether colorectal cancer is a problem in acromegaly is currently unresolved. We performed a cross-sectional study to assess the risk of colonic neoplasia in patients with acromegaly. Colonoscopic screening was performed in 235 patients with acromegaly at five tertiary care hospitals in Italy between January 1, 1996, and December 31, 2001. A repeat colonoscopy was performed in 121 patients after a mean interval of 32.1 months. Colonoscopic findings in patients with acromegaly were compared with those of 233 patients with nonspecific abdominal complaints who were referred for endoscopy during the study period. A total of 65 patients (27.7%) and 36 controls (15.5%) had colonic neoplasia. In 55 patients (23.4%) and 34 control subjects (14.6%), the most important findings were adenomas (odds ratio, 1.7; range, 1.1-2.5), whereas 10 patients (4.3%) and two control subjects (0.9%) had carcinoma (odds ratio, 4.9; range, 1.1-22.4). The risk of colonic neoplasia was higher for younger patients with acromegaly compared with age-matched controls. Patients with acromegaly with or without colonic neoplasia did not differ significantly for IGF-I levels or duration of disease. A neoplastic recurrence was found in 16.5% of patients who underwent follow-up; 90% of them had had a neoplasm removed at the first colonoscopy. Acromegaly carries with it a moderate, but definitive, increase in the risk of colonic neoplasia that occurs at a younger age than in the general population. Patients who are found to harbor a colonic neoplasia are at risk for recurrence.     

Advanced magnetic resonance imaging in benign hereditary chorea: Study of two familial cases

No brain abnormalities are usually detected on conventional magnetic resonance imaging (MRI) in benign hereditary chorea (BHC); there are currently no studies with advanced techniques in literature. We investigated whether conventional and advanced MRI techniques could depict regional brain abnormalities in two familial BHC patients and 24 healthy controls. No brain abnormalities on conventional scans were detectable; also, no significant differences in fractional anisotropy of the basal nuclei were observed. Volumetric analysis showed a decreased volume of the striatum bilaterally compared with controls, whereas spectroscopy demonstrated a significant increased myoinositol/creatine ratio bilaterally, a reduction of choline/creatine ratio bilaterally, and of N‐acetyl‐aspartate/creatine in the right putamen. With the limits of the small sample size in the patient group, these data show that, despite the absence of macroscopic changes on conventional MRI, volumetric and metabolic abnormalities are present in the basal nuclei of BHC patients. © 2010 Movement Disorder Society.     

Callosal atrophy in mild cognitive impairment and Alzheimer's disease: Different effects in different stages

Alzheimer's Disease (AD) is a neurodegenerative disorder that mainly affects grey matter (GM). Nevertheless, a number of investigations have documented white matter (WM) pathology associated with AD. The corpus callosum (CC) is the largest WM fiber bundle in the human brain. It has been shown to be susceptible to atrophy in AD mainly as a correlate of Wallerian degeneration of commissural nerve fibers of the neocortex. The aim of this study was to investigate which callosal regions are affected and whether callosal degeneration is associated with the stage of the disease. For this purpose, we analyzed high-resolution MRI data of patients with amnesic mild cognitive impairment (MCI) (n = 20), mild AD (n = 20), severe AD (n = 10), and of healthy controls (n = 20). Callosal morphology was investigated applying two different structural techniques: mesh-based geometrical modeling methods and whole-brain voxel-based analyses. Our findings indicate significant reductions in severe AD patients compared to healthy controls in anterior (genu and anterior body) and posterior (splenium) sections. In contrast, differences between healthy controls and mild AD patients or amnesic MCI patients were less pronounced and did not survive corrections for multiple comparisons. When correlating anterior and posterior WM density of the CC with GM density of the cortex in the severe AD group, we detected significant positive relationships between posterior sections of the CC and the cortex. We conclude that callosal atrophy is present predominantly in the latest stage of AD, where two mechanisms might contribute to WM alterations in severe AD: the Wallerian degeneration in posterior subregions and the myelin breakdown process in anterior subregions.     

Time to reconsider the clinical value of immunoglobulin G4 to foods?

BACKGROUND: The usefulness of serum antibodies to common food antigens (immunoglobulin G4; IgG4) assay in management of patients suffering from food intolerance was assessed. METHODS: A total of 22 asymptomatic healthy subjects and 68 patients with symptoms referred for suspected food intolerance were studied. Serum IgG4 to 19 common foods was measured by an automated immunoassay. RESULTS: The area under the receiver operating characteristic curve was 0.92 (standard error 0.04) and, at a threshold value of 2.3 U/mL, the IgG4 determination had a sensitivity of 0.81, with a specificity of 0.87. With a pre-test probability of 5% and 20%, the post-test probability of having disease was found to be 24% and 61%, respectively, and 1.1% and 5% if the result was negative. Cohen's K value (0.83) indicated a good agreement between symptoms and IgG4 concentrations. CONCLUSION: Serum IgG4 assay may play a role in rul-ing out food intolerance, because of its satisfactory negative predictive value (0.99).