Unidade de Nefrologia Pediátrica, Instituto da Criança, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
Clinics (Sao Paulo). 2009 May;64(5):409-14. doi: 10.1590/s1807-59322009000500007.
Nephrogenic diabetes insipidus is characterized by a lack of response in the distal nephron to the antidiuretic hormone arginine vasopressin. Manifestations include polyuria, polydipsia, hyposthenuria, recurrent episodes of dehydration and fever and growth failure. Most cases are caused by mutations in the AVPR2 gene. The mutant receptors are trapped intracellularly.
We studied five boys using clinical, laboratory and molecular data. The mean age at diagnosis was 14.6 months (range 6 to 24) and 12.2 years (7.8 to 19) after the follow-up period. The mean period of follow-up was 132.2 +/- 50.9 months.
The geometric means of the z-scores of weight and stature were -4.5 and -3.6, respectively, at diagnosis. At the last medical appointment, the z-scores of weight and stature were -0.3 and -0.9, respectively. Three patients were diagnosed with ureterohydronephrosis and exhibited increased post-void urine volume. Mutations in the AVPR2 gene were found in all patients, and the carrier status was confirmed in four of five cases. Two unrelated children presented identical mutations (S167L) in arginine vasopressin R2. Two of the patients had a mutation that has already been described in other Brazilian families (R337X), and one patient showed a de novo mutation (Y128D) in arginine vasopressin R2, since his mother's molecular analysis was normal. The recurrence risk for this family was significantly reduced.
This study reports the clinical and laboratory characterization of Nephrogenic diabetes insipidus and reiterates the importance of the genetic basis that underlies the disease diagnosis and genetic counseling.
肾性尿崩症的特征是远曲小管对血管加压素精氨酸加压素无反应。临床表现包括多尿、多饮、少尿、反复脱水和发热以及生长发育不良。大多数病例是由 AVPR2 基因突变引起的。突变受体被困在细胞内。
我们使用临床、实验室和分子数据研究了 5 名男孩。诊断时的平均年龄为 14.6 个月（范围为 6 至 24），随访期后为 12.2 岁（7.8 至 19）。平均随访时间为 132.2 +/- 50.9 个月。
诊断时体重和身高的 Z 分数几何平均值分别为-4.5 和-3.6。最后一次就诊时，体重和身高的 Z 分数分别为-0.3 和-0.9。3 名患者被诊断为输尿管积水，表现为排尿后尿量增加。所有患者均发现 AVPR2 基因突变，5 例中有 4 例证实为携带者状态。2 名无关的儿童表现出相同的精氨酸加压素 R2 突变（S167L）。2 名患者具有已在其他巴西家族中描述过的突变（R337X），1 名患者显示出精氨酸加压素 R2 中的新生突变（Y128D），因为他母亲的分子分析正常。该家族的复发风险显著降低。
本研究报告了肾性尿崩症的临床和实验室特征，并再次强调了疾病诊断和遗传咨询所依据的遗传基础的重要性。
