Background Schizophrenia is a heterogeneous disorder with strong genetic vulnerability. Family history of schizophrenia has been considered in genetic studies under several models. De novo genetic events seem to play a larger role in sporadic cases. Aim This study used the familial–sporadic distinction with the aim of identifying a more homogeneous phenotype to delineate the genetic and clinical complexity of schizophrenia. Setting The study was conducted at Weskoppies Hospital, Pretoria, South Africa. Methods The study included 384 participants with schizophrenia or schizoaffective disorder from the Afrikaner founder population in South Africa who are considered comparable to Caucasian patients from the United States. A comprehensive data capturing sheet was completed. Results When schizophrenia and schizoaffective disorder diagnoses were considered jointly, we found no significant differences between the sporadic and the familial groups for age at disease onset, season of birth, comorbid diagnoses, clinical symptomatology, history of suicide or marital status. When the diagnoses were examined separately, however, the sporadic schizoaffective disorder, bipolar type, was found to have a significantly lower age at onset (mean 20.6 vs. 25.3 years). Conclusion The sporadic schizoaffective disorder, bipolar type, forms a more homogeneous subgroup for genetic studies.

中文翻译：

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家族史将散发性分裂情感障碍确定为遗传研究的亚型。

背景精神分裂症是一种异质性疾病，具有很强的遗传易感性。在几种模型下的遗传研究中已经考虑了精神分裂症的家族史。从头遗传事件似乎在散发病例中发挥更大的作用。目的 本研究使用家族性-散发性区分，旨在确定更同质的表型来描述精神分裂症的遗传和临床复杂性。设置 该研究在南非比勒陀利亚的 Weskoppies 医院进行。方法 该研究包括来自南非南非荷兰语创始人人群的 384 名精神分裂症或分裂情感障碍患者，他们被认为与来自美国的高加索患者相当。完成了一份全面的数据采集表。结果当综合考虑精神分裂症和分裂情感障碍的诊断时，我们发现散发性组和家族性组在发病年龄、出生季节、合并症诊断、临床症状、自杀史或婚姻状况方面没有显着差异。然而，当对诊断进行单独检查时，发现偶发性分裂情感障碍双相型的发病年龄明显较低（平均 20.6 岁对 25.3 岁）。结论 散发性分裂情感障碍，双相型，形成一个更同质的遗传研究亚组。然而，当对诊断进行单独检查时，发现偶发性分裂情感障碍双相型的发病年龄明显较低（平均 20.6 岁对 25.3 岁）。结论 散发性分裂情感障碍，双相型，形成一个更同质的遗传研究亚组。然而，当对诊断进行单独检查时，发现偶发性分裂情感障碍双相型的发病年龄明显较低（平均 20.6 岁对 25.3 岁）。结论 散发性分裂情感障碍，双相型，形成一个更同质的遗传研究亚组。