Aim: We describe the difficulties encountered in making a diagnosis where a somatic condition manifests itself alongside psychiatric symptoms associated with possible psychiatric comorbidities. Methods: A case study is presented of a 15-year-old girl who was eventually diagnosed with ornithine transcarbamylase (OTC) deficiency (hyperammonaemia type II), following an initial diagnosis of pervasive developmental disorder, selective mutism, and anorexia nervosa. Results: The OTC disease is not fully expressed in females and its prevalence is lower than in males. Around 17–20% of female patients found with a defective OTC gene on an X chromosome can suffer from OTC deficiency that may result in elevated levels of ammonia in the blood; this occurs when one of the X chromosomes become inactivated. Patients typically present with nausea, migraines, and a history of dietary protein avoidance. In more severe cases, ataxia, confusion, hallucinations, and cerebral oedema can occur. The OTC deficiency can thus remain undiagnosed in women for many years. Conclusion: Somatic comorbidity in psychiatric inpatients is commonly found; however, such disorders are rarely diagnosed or even treated adequately.
Neuropsychobiology

中文翻译：

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作为躯体疾病的首次或单独表现的精神症状：II 型高氨血症。

目的：我们描述了在诊断时遇到的困难，其中躯体疾病与可能的精神疾病相关的精神症状同时出现。方法：介绍了一个 15 岁女孩的案例研究，在初步诊断为广泛性发育障碍、选择性缄默症和神经性厌食症后，她最终被诊断为鸟氨酸转氨甲酰酶 (OTC) 缺乏症（高氨血症 II 型）。结果： OTC疾病在女性中未完全表达，其患病率低于男性。大约 17-20% 的女性患者发现OTC有缺陷X 染色体上的基因可能患有 OTC 缺乏症，这可能导致血液中氨水平升高；当其中一条 X 染色体失活时，就会发生这种情况。患者通常表现为恶心、偏头痛和避免饮食蛋白质的病史。在更严重的情况下，会出现共济失调、意识模糊、幻觉和脑水肿。因此，女性的 OTC 缺乏症可能多年未得到诊断。结论：精神科住院患者躯体合并症常见；然而，此类疾病很少得到诊断，甚至很少得到充分治疗。
神经心理生物学