Mutations in subunits of the epithelial sodium channel cause salt wasting with hyperkalaemic acidosis, pseudohypoaldosteronism type 1.

Autosomal recessive pseudohypoaldosteronism type I is a rare life-threatening disease characterized by severe neonatal salt wasting, hyperkalaemia, metabolic acidosis, and unresponsiveness to mineralocorticoid hormones. Investigation of affected offspring of consanguineous union reveals mutations in either the alpha or beta subunits of the amiloride-sensitive epithelial sodium channel in five kindreds. These mutations are homozygous in affected subjects, co-segregate with the disease, and introduce frameshift, premature termination or missense mutations that result in loss of channel activity. These findings demonstrate the molecular basis and explain the pathophysiology of this disease.

Type I pseudohypoaldosteronism includes two clinically and genetically distinct entities with either renal or multiple target organ defects.

Type I pseudohypoaldosteronism (PHA) is a hereditary disease characterized by salt wasting resulting from target organ unresponsiveness to mineralocorticoids. We have studied two kindreds including a total of nine patients with PHA. In kindred I, the propositus presented with renal salt wasting in infancy (vomiting, failure to thrive, short stature, hyponatremia, hyperkalemia) and responded dramatically to a high salt diet (2.5 g/day). Sodium supplementation was discontinued at the age of two. In seven additional family members from three generations, clinical expression of PHA varied from asymptomatic to moderate. In affected members (propositus, mother, and two brothers), hyperaldosteronism persisted over 13 yr; however, the PRA decreased gradually to near normal values. Persistent hyperaldosteronism in the face of a decrease in PRA indicated the development of tertiary hyperaldosteronism due to autonomously functioning zona glomerulosa. The pedigree was consistent with an autosomal dominant mode of transmission with variable expression. In kindred II, the propositus, who was the product of a consanguineous marriage, developed severe renal salt losing at age 9 days. She had also increased salivary and sweat electrolytes consistent with PHA resulting from multiple organ unresponsiveness to mineralocorticoids. Life threatening episodes of salt wasting recurred beyond the age of 2 yr. At 5 yr of age she still requires high amounts of salt supplements (14 g/day). A sister died at 9 days of age with PHA symptoms. Six close relatives (parents, three siblings, maternal uncle) showed no biochemical abnormalities. This pedigree was consistent with an autosomal recessive mode of inheritance. In view of the findings on these two kindreds and the analysis of those in the literature, we conclude that type I PHA includes two clinically and genetically distinct entities with either renal or multiple target organ defects.

Metabolic clearance rates of synthetic human growth hormone in lean and obese male rhesus monkeys.

The MCR of synthetic human GH was studied in eight adult male rhesus monkeys (Macaca mulatta). Four monkeys were lean (less than 20% body fat), and four were obese (greater than 35% body fat). The monkeys were given a single bolus injection of GH (2.5 micrograms/kg BW), followed by a constant infusion of GH (250 micrograms/h) for 2.5 h. Venous blood samples were collected before the infusion and every 10 min during the infusion. In both groups a plateau of the plasma GH concentrations, indicating a steady state, was reached 70 min after the start of the infusion. The MCR of GH was calculated from the ratio of the constant GH infusion rate and the plateau plasma GH concentration in each monkey. The MCR of synthetic GH was 12.7 +/- 1.7 (+/- SD) L/24 h in the lean group and 19.5 +/- 2.9 L/24 h in the obese group (P less than 0.007). However, the MCR/kg ratio in the lean monkeys was the same as that in the obese animals. We conclude that 1) MCR of GH is directly proportional to body weight; and 2) the lower plasma GH levels in obesity may be due to an increase in its MCR not compensated for by an appropriate increase in the rate of GH secretion.

Relationship of etiology to treatment in congenital hypothyroidism.

We examined the patterns of TSH, T(4), and treatment schedules from diagnosis to 4 yr of age in 125 children (50 males anf 75 females) with congenital hypothyroidism (CH). Subjects were divided into 3 groups based on their thyroid scans: 1) athyreosis (n = 31), 2) dysgenesis (n = 54; 49 lingual and 5 hypoplastic), and 3) dyshormonogenesis (n = 40). Follow-up evaluation was carried out at 2-4 wk and 3, 6, 9, 12, 24, 36, and 48 months of age. Median gestational age, age at onset of therapy, and starting L-T(4) dose were similar in the three groups. In infants with athyreosis median screening TSH levels were higher (P < 0.02) and confirmatory T(4) levels were lower than in the other two groups (P < 0.01 vs. dysgenetic; P < 0.05 vs. dyshormonogenetic CH). During the first 6 months of therapy, mean TSH levels were highest in the athyrotic group, intermediate in the dysgenetic group, and lowest in the dyshormonogenetic group. In children with athyreosis, TSH levels normalized by 12 months of age. At 12 months dysgenetic patients had the highest TSH levels (P < 0.05). During the entire study period, TSH levels were lowest in patients with dyshormonogenesis (except at 48 months) and normalized earlier. Mean T(4) levels normalized by 2-4 weeks in all groups. At 3 and 6 months, the percentage of patients who required dose changes was highest in the athyrotic group, and at 12 months it was highest in the dysgenetic group. The athyrotic group received the highest dose of L-T(4), and dyshormonogenetic group received the lowest dose. We conclude that treatment and follow-up schedules for CH may differ in the three etiological categories based on the different hormonal patterns and responses to therapy. Children with athyreosis need close monitoring particularly early in life, whereas those with dysgenesis and dyshormonogenesis require more attention later in life.

Exclusion of the locus for autosomal recessive pseudohypoaldosteronism type 1 from the mineralocorticoid receptor gene region on human chromosome 4q by linkage analysis.

Pseudohypoaldosteronism type 1 (PHA1) is an uncommon inherited disorder characterized by salt-wasting in infancy arising from target organ unresponsiveness to mineralocorticoids. Clinical expression of the disease varies from severely affected infants who may die to apparently asymptomatic individuals. Inheritance is Mendelian and may be either autosomal dominant or autosomal recessive. A defect in the mineralocorticoid receptor has been implicated as a likely cause of PHA1. The gene for human mineralocorticoid receptor (MLR) has been cloned and physically mapped to human chromosome 4q31.1-31.2. The etiological role of MLR in autosomal recessive PHA1 was investigated by performing linkage analysis between PHA1 and three simple sequence length polymorphisms (D4S192, D4S1548, and D4S413) on chromosome 4q in 10 consanguineous families. Linkage analysis was carried out assuming autosomal recessive inheritance with full penetrance and zero phenocopy rate using the MLINK program for two-point analysis and the HOMOZ program for multipoint analysis. Lod scores of less than -2 were obtained over the whole region from D4S192 to D4S413 encompassing MLR. This provdes evidence against MLR as the site of mutations causing PHA1 in the majority of autosomal recessive families.

Type 1 diabetes in Jewish Ethiopian immigrants in Israel: HLA class II immunogenetics and contribution of new environment.

The interrelationship between human leukocyte antigen immunogenetics and environmental factors and their contribution to the emergence of type 1 diabetes (T1D) were studied in Jewish immigrants from Ethiopia in Israel. This community displays high incidence of T1D, and is unique both by its ethnic segregation and its rapid exposure to a new environment after the immigration. The study population consisted of 152 Ethiopian Jews living in Israel, 33 with T1D and 119 unrelated controls. Human leukocyte antigen class II susceptible and protective alleles in the Jewish Ethiopian patients were similar to those in patients of other ethnic groups in Israel and in non-Jewish Ethiopian patients, with a few exceptions. Three haplotypes were markedly associated with diabetes in Jewish Ethiopian patients: DRB1*0301 DQA1*05 DQB1*02 (OR 4.4, p < 0.001); DRB1*0404 DQA1 03 DQB1*0302 (OR 19.2, p = 0.006), and DRB1*0405 DQA1*03 DQB1*0302 (OR 87.8, p < 0.001). The highly susceptible allele DRB1*0301 was more common in the general Ethiopian population (25.2%) than in all other ethnic groups in Israel, which may render this community prone to the disease. The age at onset of disease in patients with two susceptible haplotypes was negatively correlated with the duration of living in Israel (r = -0.621, p = 0.04). We concluded that ongoing exposure of genetically predisposed immigrants from Ethiopia to diabetogenic environmental factors eventually leads to a high incidence of overt diabetes in this ethnic group.

Selective increases in adrenal steroidogenic capacity during acute respiratory disease in infants.

To examine steroidogenic responses of the different zones of the adrenal cortex to acute disease we determined the basal and adrenocorticotropin (ACTH)-stimulated levels of cortisol, dehydroepiandrosterone (DHEAS) and aldosterone in 16 infants aged 1-4 months with acute bronchiolitis. Fourteen of the infants were retested after recovery. During illness the mean basal levels of cortisol and DHEAS were twice as high as the levels after recovery (370 vs 180 nmol/l and 2.7 vs 1.3 mumol/l, respectively). The mean peak ACTH-stimulated levels of cortisol and DHEAS during illness were 1.5- and 2.5-fold higher, respectively, than the levels found after recovery. Although aldosterone secretion was stimulated > or = 3-fold by ACTH, illness was not associated with any change in aldosterone secretory capacity. The basal and stimulated levels of both cortisol and DHEAS during illness and after recovery were correlated significantly. Thus, the relative steroidogenic capacities for these two steroids were characteristic of the individual infant and showed constancy over a period of at least several weeks. While the levels of cortisol and aldosterone were not dependent on the age of the infants, both the basal and stimulated levels of DHEAS correlated strongly with age. We conclude that during acute disease the steroidogenic capacity selectively increases in the zones that secrete cortisol and DHEAS (only in infants < 3 months) but not in the zona glomerulosa that secretes aldosterone. The DHEAS response may be related to its putative effects to enhance immune responses.

Growth hormone activates renin-aldosterone system in children with idiopathic short stature and in a pseudohypoaldosteronism patient with a mutation in epithelial sodium channel alpha subunit.

Growth hormone (GH) treatment causes salt and water retention, and this effect has been suggested to be mediated by activation of epithelial sodium channel (ENaC). Multi-system pseudohypoaldosteronism (PHA) is a salt wasting disease resulting from mutations in ENaC subunit genes. We examined effects of GH therapy for 12-21 months on the renin-angiotensin-aldosterone system (RAAS) in 12 children with idiopathic short stature (ISS) and a PHA patient with defective ENaC function and concomitant GH deficiency. On GH therapy (0.7 U/kg/week), plasma renin activity (PRA), serum aldosterone and insulin-like growth factor-I (IGF-I) levels were periodically determined every 1-3 months in all children. The PHA patient was studied for 6 yr during which time serum, urine, and sweat electrolytes and secretion rate were also examined before, on and off GH therapy. In the PHA patient, mean plasma aldosterone concentration, 7.7 nmol/l (278 ng/dl) before therapy (n=9) rose to 73 nmol/l (2650 ng/dl) 10 months after GH. PRA and IGF-I increased similarly, reaching a plateau between 8 and 12 months. Off GH, there was a decrease to pretreatment levels in 30 months. Aldosterone and PRA strongly correlated with IGF-I (r=0.66 and 0.67). GH therapy also improved the growth rate, and increased both sweat secretion rate and Na(+)/K(+) ratio. In children with ISS, aldosterone and IGF-I peaked 6-12 months after GH. Off GH their levels normalized in 3 months. These findings indicate that long-term GH activates the RAAS in both children with ISS and a PHA patient, and that this effect does not depend on a fully functional ENaC.

Pseudohypoaldosteronism due to renal and multisystem resistance to mineralocorticoids respond differently to carbenoxolone.

Type I pseudohypoaldosteronism (PHA) is a hereditary syndrome of salt wasting resulting from unresponsiveness to mineralocorticoids. PHA is manifested in two clinically and genetically distinct forms, affecting either only the kidney or multiple target organs of aldosterone. We examined the mineralocorticoid effect of carbenoxolone (CBX) in young PHA patients with either renal or multisystem resistance to aldosterone to find out whether CBX may help reduce the requirement for a high-salt diet. CBX did not show any significant salt-retaining effect in two patients with multiple PHA, and did not affect the renin-aldosterone system. In contrast, CBX significantly suppressed the renin-aldosterone system in a renal PHA patient for the whole duration of treatment, but without a long-term salt-retaining effect. On CBX treatment, urinary cortisone levels decreased and the cortisol:cortisone ratio increased, indicating that CBX inhibited 11beta-HSD activity that metabolizes cortisol to cortisone. The complete lack of effect of CBX on the renin-aldosterone system in multisystem PHA patients indicates that CBX does not exert an effect via mineralocorticoid (MR) or glucocorticoid receptors. Examination of the structure and expression of the MR gene by Southern blot analysis and polymerase chain reaction (PCR) showed no abnormality. Whereas multiple PHA results from a spectrum of mutations in the mineralocorticoid activated epithelial sodium channel subunits, the genetic basis of renal PHA is still unknown. The response to CBX suggests that there is at least a partly functional MR in renal PHA patients.

Inheritance of familial primary endocardial fibroelastosis.

Two related families with 15 children, seven of whom developed endocardial fibroelastosis (EFE) are described. Three of the children died during infancy, and the disease was confirmed in one of them at autopsy. The survivors, two sisters age 5 years and 15 months (Family A) and two sisters age 17 and 14 years (Family B), are now symptomless and show a decrease in left ventricular hypertrophy. The mode of inheritance of EFE in our two families appears to be either autosomal or X-linked dominant with reduced penetrance.

Benign paroxysmal torticollis in infancy.

We present four children with benign paroxysmal torticollis (BPT) and a review of the literature. BPT appears to be a self-limited disorder that occurs predominantly in females. The attacks of head tilting usually start in infancy, may recur at varying intervals until the age of 1 to 5 years, and may be confused with other seizures. Other symptoms, such as ataxia and vomiting, may be associated with the attacks of torticollis. Less frequently, infantile migraine also may be associated.

Surgically curable hypophosphatemic rickets. Diagnosis and management.

Childhood hypophosphatemic rickets (HR) is most often caused by a defect in renal tubular resorption of filtered phosphorus. However, HR can also be caused by secretion of a phosphaturetic factor from a tumor. The presentation of patients with the different HR syndromes may be identical. Distinguishing between the HR syndromes is essential, however, because HR caused by renal defect requires life-long therapy with Vitamin D and phosphate replacement, but tumor-associated HR is cured by removal of the tumor. A case of hemangiopericytoma occurring in bone and causing HR is reported. Children with HR typically have normal levels of serum calcium and parathyroid hormone but very low levels of serum phosphorus. In a child with HR, the following features should prompt a thorough evaluation for a causative tumor: lack of other family members who have hypophosphatemia; presence of aminoaciduria, particularly glycinuria. Causative lesions are most commonly found in the bone or skin.

The effect of endogenous dehydroepiandrosterone sulphate on antibody response to hepatitis B vaccine in neonates.

BACKGROUND: DHEAS, the most abundant steroid secreted by the adrenal cortex, is suggested to have an important role in the development of immune reaction by activating T cell function and increasing antibody response, and has been tried as a vaccine adjuvant in elderly people. OBJECTIVES: We examined the correlation between endogenous DHEAS and antibody response in the neonatal period by comparing the serum DHEAS levels with the amount of antibody response against hepatitis B vaccination in neonates. METHODS: Vaccine was administered to 12 healthy infants within 24 hours of birth (day 0), and blood specimens were obtained on days 0 and 30 for determination of anti-hepatitis B surface antibody concentration and DHEAS levels. RESULTS: DHEAS levels varied widely (range 0.38-3.70 micrograms/ml, mean +/- 1SD 2.14 +/- 0.98). While we could identify two groups of patients--those with high DHEAS levels (2.90 +/- 0.56) and those with lower levels (1.30 +/- 0.56)--there was no correlation between DHEAS levels and the antibody response to hepatitis B vaccine (r = -0.05). CONCLUSIONS: In neonates, antibody response to hepatitis B vaccine does not correlate with DHEAS serum levels. These results do not support the usage of DHEAS as a vaccine adjuvant in neonates.

[Cyclic psychosis associated with the menstrual cycle].

Cyclic psychosis associated with the menstrual cycle is an uncommon disorder, not included under the accepted definitions of functional psychoses. We present three female adolescents who developed an acute psychosis a few days before menstruation, which resolved completely upon bleeding or several days later, only to reappear in the same form in subsequent cycles. The clinical presentation was not in line with that of the typical functional psychoses. An extensive medical work-up did not show any significant disturbances, with the exception of anovulatory cycles in one youngster. Psychotropic treatment had no effect on the course of the psychosis. Treatment with progesterone in the second half of the cycle in one case, and with a combined progesterone/estrogen contraceptive agent in another, resulted in full recovery within several cycles. The third girl showed a spontaneous remission within four cycles. Remission continued in all cases after discontinuation of the hormonal treatment, and with no need to reintroduce any psychotropic agent, for a period of 2-4 years. We discuss several possible etiologic mechanisms for cyclic psychosis associated with the menstrual cycle, including it being a cycloid non-specific affective disorder, and its association with a temporary functional hypothalamic-pituitary dysfunction, and with anovulation. We also discuss the role of psychotropic and hormonal treatment in this disorder.