Thunell S, Holmberg L, Lundgren J
J Clin Chem Clin Biochem. 1987 Jan;25(1):5-14. doi: 10.1515/cclm.1987.25.1.5.
Homozygous deficiency of aminolaevulinate dehydratase (porphobilinogen synthase, EC 4.2.1.24) was diagnosed in a small child. The clinical presentation was unique since severe symptoms were already present in the neonatal period. The patient, a boy, now three-years old, had recurrent attacks of pain, vomiting, hyponatraemia and symptoms of polyneuropathy engaging motor functions including respiration. The clinical course of the disease from birth on is related, as are the results of various attempts at therapy. The patient excreted large amounts of 5-aminolaevulinic acid and coproporphyrin and minor amounts of porphobilinogen in the urine. Faecal excretion of coproporphyrin and harderoporphyrin was increased as was erythrocyte porphyrin concentration. Diagnosis was established by the finding that erythrocyte aminolaevulinate dehydratase activity was less than 5 per cent of normal in the patient and between 26 and 51 per cent of normal in both the parents, the grandfathers and a sibling. The activity of the enzyme could not be restored by the addition of dithiothreitol (10(-3) mol/l) alone, or in combination with zinc or manganese in varying concentrations. The enzyme Km did not differ between affected and nonaffected members of the family.
在一名幼儿中诊断出氨基乙酰丙酸脱水酶（卟啉原合酶，EC 4.2.1.24）纯合子缺乏症。临床表现独特，因为在新生儿期就已出现严重症状。该患者为一名三岁男孩，反复出现疼痛、呕吐、低钠血症以及累及包括呼吸在内的运动功能的多发性神经病症状。从出生起的疾病临床过程以及各种治疗尝试的结果都有相关性。患者尿液中排泄大量的5-氨基乙酰丙酸和粪卟啉，少量的卟啉原。粪卟啉和硬卟啉的粪便排泄量增加，红细胞卟啉浓度也增加。通过发现患者红细胞氨基乙酰丙酸脱水酶活性低于正常水平的5%，而父母、祖父和一个兄弟姐妹的该酶活性在正常水平的26%至51%之间，从而确立了诊断。单独添加二硫苏糖醇（10⁻³ mol/l），或与不同浓度的锌或锰联合添加，都无法恢复该酶的活性。该酶的Km值在家族中患病和未患病成员之间没有差异。
