A case of central diabetes insipidus due to neurophysin II gene abnormality diagnosed based on a family history of nocturnal enuresis

The etiology of central diabetes insipidus (DI) is classified into (1) idiopathic, (2) familial, and (3) secondary. Of these, familial central diabetes insipidus shows an autosomal dominant inheritance. We herein report a case in which this disease was diagnosed based on a family history of nocturnal enuresis. A 40-year-old man had had symptoms of polydipsia, polyuria and nocturia since childhood and found that his daughter had the same symptoms. Despite reaching nine years old, his daughter's nocturnal enuresis still had not improved, resulting in her consulting a pediatrician. She was suspected of having familial neurohypophyseal diabetes insipidus (FNDI) based on her family history and was referred along with her father for a detailed examination and treatment. A hypertonic saline load test (HSLT) to evaluate the arginine vasopressin (AVP) reaction was performed in both the proband and his daughter. The results showed no increase in AVP levels in response to high plasma osmolality. The water deprivation test (WDT) revealed he was suffering from partial DI. Based on the above findings and considering the possibility of familial central diabetes insipidus, we performed a gene mutation analysis of AVP-neurophysin II (NPII). Both the father and daughter had an exon 2 abnormality in this gene (c232_234delGAG; pGlu78del), and this gene mutation is known to cause NPII protein abnormality, abolishing the function of AVP as a carrier protein. This case was considered to have provided an opportunity to understand the role of an NPII gene abnormality in familial central diabetes insipidus.

Possible impact of comorbid conditions on the persistence of nocturnal enuresis: results of a long-term follow-up study

PURPOSE

To describe the natural history of patients with nocturnal enuresis (NE) during a 10-year period and to evaluate possible impact of comorbid conditions on the persistence of NE.

MATERIALS AND METHODS

Ninety-five children (male to female ratio [M:F] 65:30), aged at first visit between 6 and 21 years were included in this study. Of study subjects 75 had primary monosymptomatic nocturnal enuresis (PMNE), 3 had secondary monosymptomatic nocturnal enuresis (SMNE) and 17 had non-mono­symptomatic nocturnal enuresis (NMNE). Demographic and NE-related details were assessed from electron­ic medical records and by telephone interview at the times 3, 6, 12 months and 3, 5, 10 years after the first examination. Sixty-seven of 95 patients were enrolled, of whom 57 had PMNE (M:F ratio 39:18, mean age 9.35 ± 2.81 years, mean age at improvement 11.5 ± 4.08 years), 8 had NMNE (M:F ratio 4:4, mean age 10.1 ± 2.64 years, mean age at improvement 12.6 ± 1.68 years) and 2 had SMNE (M:F ratio 1:1, mean age 12 years, mean age at improvement 13.5 ± 2.12 years).

RESULTS

The mean duration of follow up was 7.2 ± 2.5 years. All of the 67 children had 5 years follow up. Only 29 of 67 patients (19 with PMNE, 8 with NMNE and 2 with SMNE) had 10 years follow up and 4 of 19 with PMNE were still affected by NE. Out of 57 patients with PMNE 12 (2/12 with language disorders, 1/12 varicocele and 1/12 cryptorchidism) and out of 8 patients with NMNE 1 were still enuretic while all patients with SMNE were in remission.

CONCLUSION

We observed that language disorders and testicular pathology in NE children could be comor­bidities associated with persistence of NE and treatment resistance.

Prevalence of nocturnal enuresis and associated factors in schoolchildren in Western Turkey

INTRODUCTION

The prevalence of nocturnal enuresis (NE) in pediatric populations varies between 1% to 20%. The aim of this study was to determine the prevalence of NE in schoolchildren living in Tekirdag, a city in Western Turkey.

MATERIALS AND METHODS

We distributed a questionnaire to 11324 schoolchildren aged 7 to 14 years who were living in Tekirdag. The questionnaires were filled in by the children's parents. The main study endpoints were the prevalence of NE, and its association with sociodemographic factors of the children and their parents.

RESULTS

The results from 9210 children (81.4%) who returned fully completed questionnaires were included in the study. The prevalence of NE was 7.5%. Another 579 children (6.2%) had NE that had resolved at the time of study. Prevalence rates decreased with increasing age, reaching 1.4% by age 14 years. NE was more prevalent among boys than girls, but the rates became similar by age 12 years. There was a strong relationship between NE and family history of childhood NE. More than half of the parents who had a child with NE were using traditional techniques for treatment.

CONCLUSIONS

The prevalence of NE in schoolchildren in Tekirdag, a city in Western Turkey was 7.5%. Having a family history of childhood NE was the one of main risk factors for NE.

Behavioural genetics of childhood disorders

After a general introduction into genetic risk factors for child psychiatric disorders, four specific child psychiatric disorders with a strong genetic component, namely, Autism Spectrum Disorders, Attention Deficit / Hyperactivity Disorder, Nocturnal Enuresis, and obesity, are discussed in detail. Recent evidence of linkage, candidate gene, and genome-wide association studies are presented. This chapter ends with a prospectus on further research needs.

Nitric Oxide Synthase Gene Polymorphisms in Children with Primary Nocturnal Enuresis: A Preliminary Study

AIMS

Recent studies demonstrated some differences in urinary electrolytes of enuretic children. Intrarenal nitric oxide (NO) serves as a major regulator of renal sodium and water excretion like an endogenous diuretic. This study aimed to investigate endothelial (eNOS), and neuronal (nNOS) NO synthase gene polymorphisms in children with primary nocturnal enuresis (PNE).

MATERIALS AND METHODS

The eNOS gene polymorphism was investigated in 171 Turkish children (57 PNE cases and 114 healthy, non-enuretic controls), and nNOS gene polymorphism was determined in 158 Turkish children (83 PNE cases and 75 healthy, non-enuretic controls). The glu298asp (G/T) polymorphism of the eNOS and C276T (C/T) polymorphism of nNOS genes were genotyped using PCR.

RESULTS

The distribution of GG, TG, and TT genotypes for eNOS gene was 48%, 33%, and 19% in PNE, compared with 61%, 26%, and 13% in the controls (p > 0.05). The distribution of CC, TC, TT and genotypes for nNOS gene was 31%, 29%, and 40% in PNE compared with 10%, 43%, and 47% in the controls. CC genotype was found higher in enuretic children (p = 0.002). The eNOS and nNOS gene polymorphisms were not associated with positive family history, frequency of enuresis, and clinical response to desmopressin.

CONCLUSIONS

This study is the first to search the NOS gene polymorphisms in children with PNE. It was determined that eNOS gene polymorphism may not be associated with PNE, while nNOS gene polymorphism, a predominantly CC genotype, may be associated with PNE in Turkish children. Further studies with larger samples together with the detection of enuresis gene may help determine the exact role of nNOS gene polymorphism in enuresis.

[Relationship between dopamine D4 receptor gene polymorphisms and primary nocturnal enuresis]

OBJECTIVE

To study polymorphisms of dopamine D4 receptor (DRD4) in children with primary nocturnal enuresis (PNE) and explore the relationship between DRD4 gene polymorphisms and PNE.

METHODS

Genomic DNA was isolated from leukocytes in 86 unrelated children with PNE and in 100 healthy unrelated children (controls). Polymorphisms of DRD4-1240L/S, -616C/G and -521C/T were genotyped by allele-specific primer PCR.

RESULTS

There were significant differences in allele frequencies (x2=8.13, P<0.05) and genotypes frequencies (x2=6.23, P<0.05) of DRD4-616C/G between PNE patients and healthy controls. The frequency of haplotype LCT consisting of 3 function polymorphic sites DRD4-1240L/S, -616C/G and -521C/T in PNE patients was statistically higher than that in healthy controls (x2=5.88, P<0.05).

CONCLUSIONS

The change of C to G of DRD4-616 may affect the induction and transcription of DRD4 gene. The haplotype LCT consisting of 3 function polymorphic sites DRD4-1240L/S, -616C/G and -521C/T may synergistically inhibit the transcription activity of DRD4 gene. This might lead to a reduction of DRD4 protein expression and cause nocturnal enuresis.

Family and segregation studies: 411 Chinese children with primary nocturnal enuresis

BACKGROUND

The aim of the present paper was to determine the incidence of primary nocturnal enuresis (PNE) among relatives of Chinese children with PNE, the inheritance pattern, and to identify the characteristics of PNE with positive family history.

METHODS

From July 2003 to June 2004, an epidemiological survey on PNE children was carried out by self-administered questionnaires to parents of 5-18-year-old Chinese students in Henan Province, central China. A detailed family history was recorded in order to determine the presence of familial PNE as defined as any close relative with PNE beyond the age of 5 years.

RESULTS

The response rate was 88% (10 383/11 799), and 411 children (235 boys and 176 girls) with PNE were identified. A positive family history was found in 94 families (22.87%) of 411 probands with PNE, including 48.94% of fathers, 8.51% of mothers, 6.38% of both parents, 6.38% of the siblings and 29.79% of grandfathers or (and) mothers. Among the probands the ratio of male to female was 1.3:1 excluding sex-linked inheritance. Autosomal dominant inheritance was in 14.60%, and autosomal recessive inheritance was consistent in 1.46% of families. In PNE children with positive family history, the proportion of adolescents, with associated daytime symptoms, marked PNE and seeking professional help were significantly higher than those in PNE children without positive family history.

CONCLUSIONS

PNE has a significant family clustering, and all modes of inheritance can occur in different families on the basis of a formal genetic analysis. Those with positive family history often manifest marked PNE, and have daytime symptoms.

Relief of Nocturnal Enuresis by Desmopressin Is Kidney and Vasopressin Type 2 Receptor Independent

Primary nocturnal enuresis (PNE) is a common problem in childhood and adolescence. Although various treatments are highly effective, a common underlying hypothesis on the pathogenesis is lacking. The success of desmopressin, a synthetic analogue of the antidiuretic hormone vasopressin, has been attributed to increased renal water reabsorption that is mediated by activation of the renal vasopressin V2 receptor (V2R). However, this effect does not explain other symptoms of PNE, such as the failure to arouse upon bladder distension. This study identified a family in which one child displayed PNE and coexisting nephrogenic diabetes insipidus, as a result of a novel nonsense mutation in the V2R gene (C358X). Cell-biologic investigations revealed that V2R-C358X is retained in the endoplasmic reticulum and is unstable, which explains his nephrogenic diabetes insipidus. Consistently, extrarenal V2R-mediated responses were absent in the patient who was treated with desmopressin. Administration of desmopressin, however, changed his PNE into nocturia, because he now still voided unchanged high urinary volumes at night but woke up and went to the bathroom. Withdrawal of desmopressin was accompanied by bedwetting, whereas reintroduction again relieved the symptoms. Therefore, these data indicate that neither a functioning renal concentration system nor a functional V2R is needed for the therapeutic benefit of desmopressin in PNE. Rather, it suggests that another vasopressin receptor and other organ(s) is the target for desmopressin to relieve PNE.

The genetic basis of inherited primary nocturnal enuresis: A UAE study

OBJECTIVE

Nocturnal enuresis is defined as involuntary emptying of the bladder in the absence of an organic cause in a child aged 5 years or older. Primary nocturnal enuresis (PNE) is the term used if the child has never been dry. Of several factors implicated in the etiology of PNE, genetic factors appear to be the strongest. In about 75% of affected children, there is a strong family history. The purpose of this study was to examine the genetic basis of nocturnal enuresis among children in the United Arab Emirates (UAE).

METHODS

Chromosomes 12 and 13 were genotyped in all family members of 10 affected children in four large families. Linkage to earlier reported microsatellite markers on these two chromosomes was examined.

RESULTS

In the four families examined, we did not find evidence for linkage to the two loci reported previously.

CONCLUSIONS

Among UAE children examined, no linkage was found between PNE and the loci reported previously on chromosomes 12 and 13, indicating further genetic heterogeneity in PNE.