Science 321(5886): 218-23. Introduction

This article begins with a discussion of autism spectrum disorders and the social and mental impairments that typify the disorder, setting up an approach that is inherently humanistic and person-centered. Despite the highly technical and quantified nature of the ultimate research question and data collected and analyzed in this study, this person-centered focus and tone is observable throughout this research article. Immediately following a brief description of the impacts of autism spectrum disorders on individuals that have these disorders, the authors launch into a discussion regarding the evidence for a hereditary pattern in the development of the disorder and the ability to trace the disorder and its impact through families.

The authors follow this with a discussion about one of the general methodologies they ultimately employ in this research, known as "homozygosity mapping," which essentially is a method of genetic analysis that examines genomes with shared ancestry as a means of discovering autosomal recessive genotypes that lead to disorders. The specific research conducted by the authors is, naturally, a combination of these two primary trends discussed in the front sections of their article: an application of this homozygosity mapping technique to the study of autism spectrum disorders, for the purpose of illuminating specific potential genetic factors influencing the emergence of autism spectrum disorders. Throughout, this is guided by a stated desire to improve the quality of life for individuals and families dealing with autism spectrum disorders.

Methods

A total of one hundred and four families were recruited through the Homozygosity Mapping Collaborative for Autism; eighty eight of these families had marriages between cousins, which were especially useful for this study. All families from the Arabic Middle East, Turkey, and Paksitan. The DSM-IV-TR was used as a diagnostic instrument for assessing and identifying autism spectrum disorders, in all cases confirming previous diagnosis by a licensed physician...

Homozygosity mapping was performed by obtaining full genomic testing on all available family members for each of the identified families, and cross comparing results both within and between families was conducted in order to determine potential correlations and to highlight any observed differences.
Results

The results of this research are multifaceted and not entirely straightforward. Intrafamily analysis suggested that certain genetic expressions were definitely factors in correlated to the development of autism spectrum disorders, while comparisons of the multiple families in the study revealed a large degree of heterogeneity that suggests a multitude of different and independent gene loci can be involved in the development of these disorders. In short, the general belief that there is are genetic factors largely responsible for the development of autism spectrum disorders seems to have been borne out, but the hope of providing specific loci information not only went unfulfilled, but appears to be even further out of reach.

Discussion

The authors situate their research in an emerging trend that suggests a large degree of heterogeneity in individuals with autism spectrum disorders, while at the same time proffering homozygosity mapping as an effective means of obtaining useful information regarding genetic factors in autism spectrum disorders despite this heterogeneity. Though autism is influenced by many different specific gene loci, that is, there is still a great deal of both academic and practical value in identifying these many different genetic areas. This research also helped to identify certain specific loci that, while perhaps quite rare in actually affecting autism, are definitely correlated with the development of autism spectrum disorders in the families studied and thus represent additions to the growing pool of rare autism-associated loci. All of this research helps to build the comprehensive body of knowledge regarding autism, enabling future discoveries to have wider impacts and more comprehensively analyzed results.