Prospective cohort study of phenotypic variation based on an anal sphincter function in adults with fecal incontinence.

BACKGROUND: One-third of patients with fecal incontinence (FI) do not have any anal dysfunction. The aim was to characterize patients with FI with normal anal function compared with patients with anal weakness. METHODS: The general characteristics and data of anal manometry, endosonography, and defecography of patients who were evaluated for FI at a single institution from 2005 to 2015 were prospectively assessed. Fecal incontinence was defined by the Cleveland Clinic Incontinence Score (CCIS) >4. Anal weakness was defined by one or more of the three following parameters: <25 mmHg at the upper part of the anal canal, <26 mmHg at the lower part of the anal canal, and <60 mmHg for the mean squeeze pressure. KEY RESULTS: A total of 439 patients with FI were included (152 with normal anal function/287 with anal weakness). Severe constipation (Kess score ≥21) was predominant in patients with normal anal function (44/151 vs 50/284, respectively; p = 0.0054). Fecal incontinence with normal anal function was significantly associated with lower age (>63 years; odds ratio [OR] = 0.29), higher weight (>65 kg; OR = 1.69), fecal urgency (OR = 1.58), less severe FI score (CCIS score >10; OR = 0.52), higher abdominal pressure (>36 mmHg; OR = 2.15), and paradoxical puborectal contraction (OR = 2.07) in a multivariate analysis model. CONCLUSION & INFERENCES: Fecal incontinence with normal anal function is a specific phenotype that involves distal constipation and may be an early stage of FI with anal weakness. Physicians should adapt their management to focus on the treatment of constipation.

HETEROZYGOSITY AND GROWTH IN MARINE BIVALVES: FURTHER DATA AND POSSIBLE EXPLANATIONS.

In a natural population of two-year-old mussels, shell length was correlated with degree of heterozygosity. There was no correlation between an individual's glycogen level and its degree of heterozygosity, but when individuals were grouped in heterozygosity classes a near-significant correlation was observed between degree of heterozygosity and mean glycogen level corrected for the effects of sex and stage of gonad development. There was no correlation between degree of heterozygosity and index of gonad development. Such a correlation would have provided support for the hypothesis (Zouros and Foltz, 1984) that dependence of time of spawning on heterozygosity may explain the observed heterozygote-deficiency. The causes of heterozygote-deficiency, a common phenomenon in populations of marine bivalves, remain obscure. The observed heterozygosity-growth correlation is examined in the light of the controversy of whether allozymes act as markers in linkage association with genetic conditions that are responsible for the differences in growth among individuals or are themselves the agents of the correlation. The observations that 1) the contributions of individual loci to the correlation vary among populations, 2) the correlation is observed in samples from natural populations but not among progeny from pair matings, and 3) the correlation is nearly always accompanied with heterozygote-deficiency in the population are more compatible with the first explanation and suggest that the growth-heterozygosity correlation results mostly from associative overdominance and to a lesser extent from the direct contributions of scored loci to growth.

A comment on the use of Nass's contingency test for random association of alleles at different loci.

A chi 2 test developed by Nass (1959) and recently used by Ahmad and Hedrick (1985) for the detection of non-random association between alleles of different loci is very sensitive to misclassification of genotypes.