Association of rare missense variants in the second intracellular loop of NaV1.7 sodium channels with familial autism

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder often accompanied by intellectual disability, language impairment and medical co-morbidities. The heritability of autism is high and multiple genes have been implicated as causal. However, most of these genes have been identified in de novo cases. To further the understanding of familial autism, we performed whole-exome sequencing on five families in which second- and third-degree relatives were affected. By focusing on novel and protein-altering variants, we identified a small set of candidate genes. Among these, a novel private missense C1143F variant in the second intracellular loop of the voltage-gated sodium channel Na_V1.7, encoded by the SCN9A gene, was identified in one family. Through electrophysiological analysis, we show that Na_V1.7^C1143F exhibits partial loss-of-function effects, resulting in slower recovery from inactivation and decreased excitability in cultured cortical neurons. Furthermore, for the same intracellular loop of Na_V1.7, we found an excess of rare variants in a case-control variant-burden study. Functional analysis of one of these variants, M932L/V991L, also demonstrated reduced firing in cortical neurons. However, although this variant is rare in Caucasians, it is frequent in Latino population, suggesting that genetic background can alter its effects on phenotype. Although the involvement of the SCN1A and SCN2A genes encoding Na_V1.1 and Na_V1.2 channels in de novo ASD has previously been demonstrated, our study indicates the involvement of inherited SCN9A variants and partial loss-of-function of Na_V1.7 channels in the etiology of rare familial ASD.

Evaluating interviewing techniques for the sexual practices history. Use of video trigger tapes to assess patient comfort

BACKGROUND

Although physicians recognize the importance of assessing a patient's risk for human immunodeficiency virus (HIV) infection, many are reluctant to explore a person's sexual history, a principal determinant of this risk.

OBJECTIVE

To examine the feasibility of a research design that uses responses to viewing a videotaped interview as a proxy for how patients might feel if they were interviewed using a specific approach, and to determine comfort levels with a variety of interview approaches for conducting HIV risk assessment.

METHODS

Individuals responded to a videotape of several interviewing approaches for HIV risk assessment. Responses to the following aspects were collected: introduction of HIV risk assessment, assessment of patient comfort with the topic, techniques for collecting HIV risk and sexual information, and exploration of sensitive issues not previously identified. Participants expressed levels of comfort by means of a Likert scale to rate their comfort with each approach.

RESULTS

Participants expressed higher comfort levels with an introduction that used a ubiquity statement or lifestyle bridge question. Also, they expressed greater comfort when the interviewer addressed how they felt about responding to questions about their HIV risk. Participants reported highest levels of comfort with both patient-centered and closed-ended interviewing techniques. Women were less comfortable with an open-ended interviewing technique.

CONCLUSIONS

Individuals have different comfort levels for approaches used to assess HIV risk. This trigger tape experimental design to assess comfort levels for interview techniques is feasible for exploring other aspects of physician-patient communication; additional validation studies are recommended.

A new era for hospital liability

Hospitals are no longer merely facilities with equipment where autonomous physicians practice; they owe a direct duty of reasonable care to patients. This dramatic transition for hospitals will ensure a sea of change in the character of hospital medical practice and management.