Severe combined adrenal and gonadal deficiency caused by novel mutations in the cholesterol side chain cleavage enzyme, P450scc

CONTEXT

Mitochondrial cytochrome P450scc converts cholesterol to pregnenolone in all steroidogenic tissues. Although progesterone production from the fetally-derived placenta is necessary to maintain pregnancy to term, four patients with mutations in the gene encoding P450scc (CYP11A1), have been described, one in a 46,XX female and three in underandrogenized 46,XY individuals, all with primary adrenal failure.

OBJECTIVE

Our aim was to determine whether P450scc mutations might be found in other children and to explore genotype/phenotype correlations.

METHODS AND PATIENTS

We performed mutational analysis of CYP11A1 in individuals with 46,XY disorders of sex development and primary adrenal failure, followed by functional studies of P450scc activity and of P450scc RNA splicing.

RESULTS

Among nine 46,XY infants with adrenal failure and disordered sexual differentiation, two infants had compound heterozygous mutations in CYP11A1. One patient harbored the novel P450scc missense mutations L141W and V415E, which retained 38 and 0% activity, respectively. The other carried a CYP11A1 frameshift mutation c835delA (0% activity) and a splice site mutation [IVS3+(2-3)insT] that prevented correct splicing of P450scc mRNA.

CONCLUSIONS

P450scc deficiency is a recently recognized disorder that may be more frequent than originally thought. The phenotypic spectrum ranges from severe loss-of-function mutations associated with prematurity, complete underandrogenization, and severe, early-onset adrenal failure, to partial deficiencies found in children born at term with clitoromegaly and later-onset adrenal failure. In contradistinction to congenital lipoid adrenal hyperplasia caused by steroidogenic acute regulatory protein mutations, adrenal hyperplasia has not been reported in any of the six patients with P450scc deficiency.

Congenital adrenal hypoplasia and male pseudohermaphroditism due to DAX1 mutation, SF1 mutation or neither: a patient report

A 15 year-old African American phenotypic female with congenital adrenal hypoplasia and intra-abdominal testes is described; she received cortisone acetate, 9alpha-Florinef, Premarin and Provera for maintenance therapy. Evaluation for DAX1, SF1 mutations using Southern blotting, PCR, PCR amplification, coding sequences, and splice site analyses have not detected any genetic abnormalities. While only 30% of the reported DAX1 mutation defects have been identified by a variety of genetic laboratory techniques, it remains probable that this unusual patient has either a DAX1 or SF1 mutation defect. A Wnt-4 defect was not evaluated.

Monozygotic twins with congenital adrenal hyperplasia: long-term endocrine evaluation and gene analysis

Monozygotic female twins with congenital adrenal hyperplasia due to 21-hydroxylase deficiency are described and evaluated over the first 6 years of life. Despite appropriate steroids, NaCl, and fludrocortisone therapies, there was significant fluctuation in the suppression of adrenal steroid secretion. Advanced bone maturation in both was noted. For the first time, molecular genetic analysis was performed and documented that the twins were compound heterozygotes for two different mutations: the maternal allele carried the 8-bp deletion mutation, whereas the paternal allele carried the 1172N missense mutation. Parental DNA samples confirmed that the mutations were on different alleles.

Familial dysalbuminemic hyperthyroxinemia: a rare example of albumin polymorphism and its rapid molecular diagnosis

Familial dysalbuminemic hyperthyroxinemia (FDH) is the most common cause of euthyroid hyperthyroxinemia, although a rare example of albumin polymorphism. FDH is inherited in an autosomal dominant manner and is characterized by enhanced binding of thyroxine to a mutant form of albumin, probably at Site 1, subdomain 11A. Previous laboratory tests of FDH have been cumbersome, rarely available, and required demonstration of anti-albumin precipitable T4, isoelectric focusing of serum for albumin in presence of labeled T4 and, occasionally, comparison of the concentrations of metabolites of T4 that have different binding affinities to the abnormal albumin. Recent studies have shown that the same mutation in the albumin gene that results in FDH has been found in 13 unrelated families. A G-->A transition in codon 218 of the albumin gene resulted in the replacement of arginine with histidine. An intragenic Sac-1 polymorphic site was found in association with the specific FDH mutation, suggesting a founder effect. FDH in our Hispanic family was confirmed by isoelectric focusing of serum. Results of thyroid function tests in our affected patients were typical for the phenotype: high total T4 and normal total T3. Genomic DNA was amplified by PCR using a mismatched oligonucleotide primer that produced a unique restriction site (Dra III) only if the DNA sample contained the mutation in codon 218: CGC (Arg) to CAC (His). In affected individuals of this family expression of the FDH phenotype was associated with the presence of His218 in one of the two alleles. Analysis linking the FDH mutation to the Sac-1 polymorphism in this family was not informative. DNA analysis is a rapid and simple method to diagnose FDH in individuals with euthyroid hyperthyroxinemia.

Transient neonatal diabetes mellitus, type 4, type 1 diabetes mellitus, or MODY: which disease is it, anyway?

A 30year-old Hispanic male who presented with transient neonatal diabetes mellitus at 4 months has been intensively studied with 12 islet-cell secretagogues from 4 months to 24 years. He was both ICA- and GAD-65-negative, but at 28 years was diagnosed with hypothyroidism due to positive thyroperoxidase antibodies. The course of his disease(s) and the various presentations of hyperglycemia are documented and illustrated by the responses in islet cell hormone secretion, namely, insulin, glucagon, and C-peptide. Insulin secretion gradually fell over 24 years, glucagon secretion persisted from infancy to 24 years but was only minimal during i.v. glucose at 24 years, and C-peptide secretion remained normal, although modest, throughout the 24 years. These data suggest that, despite changing presentations of diabetes mellitus over time, the islets continued to process proinsulin, although the patient required insulin therapy.

C-peptide and glucagon profiles in minority children with type 2 diabetes mellitus

The present study was conducted to determine the extent of insulin deficiency and glucagon excess in the hyperglycemia of type 2 diabetes in children. The incidence of type 2 diabetes mellitus in children and adolescents has increased substantially over the past several years. Because insulin and glucagon action both regulate blood glucose concentration, we studied their responses to mixed meals in children with type 2 diabetes. Subjects were 24 patients with type 2 diabetes compared with 24 controls, aged 9--20 yr (predominantly African-Americans), matched for body mass index and sexual maturation. All of those with diabetes were negative for antibodies to glutamic acid decarboxylase. Plasma glucose, glucagon, and serum C-peptide concentrations were measured at 0, 30, 60, 90, and 120 min after a mixed liquid meal (Sustacal) ingestion (7 mL/kg body weight; maximum, 360 mL). The area under the curve (AUC) was calculated by trapezoidal estimation. The incremental C-peptide (Delta CP) in response to the mixed meal was calculated (peak -- fasting C-peptide). The plasma glucose AUC was significantly greater in patients than in controls (mean +/- SEM, 1231 +/- 138 vs. 591 +/- 13 mmol/L x min; P < 0.001). The Delta CP was significantly lower in those with diabetes than in controls (1168 +/- 162 vs. 1814 +/- 222 pmol/L; P < 0.02). Glucagon responses did not differ between the two groups. Hyperglycemia is known to inhibit glucagon secretion. Therefore, our patients with substantial hyperglycemia would be expected to have decreased glucagon responses compared with controls and are thus relatively hyperglucagonemic. Patients were divided into poorly and well controlled subgroups (glycosylated hemoglobin A(1c), > or =7.2% and <7.2%, respectively). There were no significant differences in the Delta CP and glucagon responses between these two subgroups. We next analyzed the data in terms of duration of diabetes (long term, > or =1 yr; short term, <1 yr). The CP was significantly lower in long- vs. short-term patients (768 +/- 232 vs. 1407 +/- 199 pmol/L; P < 0.05). The plasma glucagon AUC was significantly higher in the long- vs. short-term patients (9029 +/- 976 vs. 6074 +/- 291 ng/L x min; P < 0.001). Hemoglobin A(1c) did not differ between long- vs. short-term patients. Our results indicate that relative hypoinsulinemia and hyperglucagonemia represent the pancreatic beta- and alpha-cell dysfunctions in children with type 2 diabetes. The severity of both beta- and alpha-cell dysfunctions appears to be determined by the duration of diabetes.

Pheochromocytoma: clinical observations from a Brooklyn tertiary hospital

OBJECTIVE

To report eight cases of pheochromocytoma, diagnosed and treated at our tertiary hospital during a 42-month period.

METHODS

We review clinical manifestations as well as historical and family data. Biochemical and radiologic methods for diagnosis and tumor localization at our institution were compared with methods at other teaching centers.

RESULTS

Among 4,180 patients with essential hypertension encountered during a 42-month interval, 8 had pheochromocytoma. The most common clinical findings were diaphoresis, chest or abdominal pain, palpitations, headaches, and nausea. Clinical features were remarkable only for the significant correlation between urinary excretion of vanillylmandelic acid and tumor volume (r = 0.925; P<0.01). Only one patient, with a history of medullary thyroid carcinoma, had multiple endocrine neoplasia. No unusual familial concentration of pheochromocytomas was found in our community, and our diagnostic techniques were similar to those reported from other institutions. We calculated an average annual incidence rate of 0.5 per 100,000 person-years, a figure comparable to that reported at the Mayo Clinic in Rochester, Minnesota.

CONCLUSION

Because our institution does not see the volume of referral patients as does the Mayo Clinic, we suggest that the frequency of pheochromocytoma may be underestimated in the patient population that we serve.

Decreased T3 and T4 levels following topical application of povidone-iodine in premature neonates

Thyroid function and iodine levels of 30 preterm neonates were examined before and up to five days after topical exposure to 10% povidone-iodine application. Urinary iodine excretion significantly increased in the group closest to term (8.9 +/- 1.2 mg I/g creatinine x 10) vs controls (3.5 +/- 0.5 mg; p < 0.01). T3 levels significantly decreased at all sub-group gestational ages vs controls (p < 0.01-0.05). Similarly, both FT4 and TT4 levels were lower in the subgroups vs controls (p < 0.01-0.05). TSH levels however did not rise in any group. These data suggest partial failure of thyroid hormone synthesis, in a population of high-risk infants possibly already exhibiting features of the euthyroid-sick syndrome. Topical iodine-containing antiseptic solutions should be used with caution in this population since these antiseptics may modify serum thyroid hormone concentrations rapidly.

Mother-daughter interaction and adherence to diabetes regimens

This study explores the relationship of mother-daughter interaction to adherence to treatment plans among diabetic adolescents. Fifty mother-daughter dyads discussed conflict issues and feelings, problems, and concerns related to diabetes. Discussions were analyzed using the Hill Interaction Matrix and modified Beavers-Timberlawn Family Evaluation Scales. Interview questionnaires provided information on adherence, feelings, problems and concerns, parental supervision, adjustment, and family life. The less adherent the adolescent, the more emotionally charged the interaction, the more directly confrontive mother and daughter were, and the less efficient they were at negotiating issues. The adolescent's statements about herself confirmed observations that poor adherers, more than good adherers, had difficulty discussing feelings, problems, and concerns with their mothers (r = -0.51, P less than or equal to 0.001). Poor adherers reported believing less strongly that adherence would delay/avoid complications (r = 0.51, P less than or equal to 0.001), became more anxious about seeing a disabled diabetic person (r = -0.29, P less than or equal to 0.29), and worried more about future health (r = -0.27, P = NS). No relationships were found between adherence and adolescent-physician rapport. Many adolescents were not engaging in good self-care behaviors, were quite concerned about future health, perceived mothers to be very concerned, hesitated telling peers about their illness, and did not share deeper illness-related concerns with their closest nondiabetic friends.

Decreased prolactin secretion in childhood obesity

Twelve obese patients and 7 control subjects, age and sex matched, whose weights were greater than 200% of ideal weight and 100% of ideal body weight, respectively, underwent intravenous insulin and thyroid releasing hormone (TRH) tests. Serial prolactin growth hormone, insulin, blood sugar, cortisol, glucagon, thyrotropin stimulating hormone, thyroxine, and triiodothyronine were obtained by RIA. Obese patients showed no significant differences from controls in basal and nadir glucose, basal and peak glucagon, cortisol, and thyroid responses to both tests. Basal insulin levels were higher (36 +/- 9.4 vs 10 +/- 2.3 microU/ml, P less than 0.05) and peak growth hormone responses after insulin were lower in the obese group (6.1 +/- 1.1 vs 12.7 +/- 3.7 ng/ml, P less than 0.05) than in controls. Whereas all control subjects had prolactin responses to both tests, five of 12 obese patients had no responses to insulin. Obese patients had lower prolactin responses at 30 minutes after insulin (5.4 +/- 0.7 vs 12.9 +/- 3.7 ng/ml, P less than 0.05) and lower prolactin responses at 60 minutes after TRH (9.9 +/- 1.7 vs 20.4 +/- 5.9 ng/ml, P less than 0.05). Maximum prolactin responses after TRH were lower in obese patients (9.9 +/- 2.0 vs 28.8 +/- 10.9 ng/ml, P less than 0.05). Maximum prolactin responses after insulin were lower in obese patients (6.2 +/- 4.1 vs 28.9 +/- 18.3 ng/ml). Thus prolactin secretion in childhood obesity is decreased after both stimuli, but more so after IV insulin that TRH, and suggests that, as in adult hypothalamic obesity, neuroendocrine regulation of prolactin release in obese children is impaired.

Essential hypernatraemia, antidiuretic hormone and neurophysin secretion: response to chlorpropamide

An adolescent boy with essential hypernatremia, absent corpus callosum, mental retardation, hypodipsia, and partial diabetes insipidus with "inappropriate" ADH regulation and secretion was studied regarding factors controlling ADH and neurophysin release. Persistent hyperosmolality was noted while on 100 mEq sodium intake daily. Endogenous vasopressin activity was demonstrated after prolonged water deprivation. Hypertonic saline infusion produced increased volumes but dilute urine. Aqueous pitressin increased urinary osmolality, decreased serum osmolality, urine flow rate, and free water clearance. Stable water diuresis was induced by water loading and on normal saline infusion. Nicotine-stimulated neurophysin remained unexpectedly low and below the level of detectability when sampled during the physiologic studies, whereas oestrogen-stimulated neurophysin was elevated during oestrogen stimulation, water loading, and orthostasis procedures. Plasma vasopressin was suppressed with water loading but remained suppressed 90 min after tilt table testing. These data indicate impairment of the osmoreceptor mechanism: however, since the patient had a normal response of oestrogen-stimulated neurophysin, that part of the neurohypophysis appears intact. Chlorpropamide was effective in alleviating the hyperosmolar state acutely and maintained normal osmolar concentrations during two years of therapy.

Turner's syndrome and carbohydrate metabolism. II. Parotid salivary insulin concentration in normal subjects and in patients with gonadal dysgenesis

Ten children with XO gonadal dysgenesis and ten control siblings (CS) had sequential IV tolbutamide and IM glucagon tests to ascertain serum and salivary insulin concentrations, to confirm the presence of parotid salivary insulin and to determine if these concentrations were of diagnostic value in the diagnosis of insulin deficiency. After tolbutamide, peak serum insulin concentrations were lower in the patients with Turner's syndrome (TS) than in control siblings (58 +/- 10 vs 90 +/- 15 microU/ml) and fractional areas under insulin curves were significantly lower in the patients with Turner's syndrome at 10 to 15 minutes (TS: 240 +/- 16 microUmin/ml; CS: 340 +/- 46 microU-min/ml, P less than 0.05) and at 15 to 30 minutes (TS: 562 +/- 62 microU-min/ml; CS: 884 +/- 128 microU-min/ml, P less than 0.05). After glucagon, peak serum insulin concentrations were significantly lower in Turner's syndrome than in control siblings(P less than 0.02, at 45 minutes) and fractional areas under insulin curves were also lower in TS than in siblings at 30 to 45 minutes (TS: 1,062 +/- 185 microU-min/ml; CS: 2,189 +/- 402 microU-min/ml, P less than 0.02). Basal salivary immunoreactive insulin (IR) concentrations were similar in both groups: TS: 4.8 +/- 2.1 microU/min; CS: 2.1 +/- 0.4 microU/min. Peak salivary IRI concentrations after tolbutamide were 13.8 +/- 4.7 microU/min in Turner's syndrome and 8.8 +/- 1.8 microU/ml in control siblings. Peak salivary IRI values in Turner's syndrome and in control siblings after glucagon were 26.8 +/- 10.1 and 13.4 +/- 2.1 microU/min, respectively. While significant differces in insulin secretion in serum were detected in the two patient groups, no differences were noted between groups when salivary insulin concentrations were compared. These data confirm serum insulin deficiency in gonadal dysgenesis, the presence of immunoreactive insulin in parotid saliva, and suggest the possibility that extrapancreatic insulin synthesis could occur in the parotid gland.

Turner's syndrome and carbohydrate metabolism. I. Impaired insulin secretion after tolbutamide and glucagon stimulation tests: evidence of insulin deficiency

Tolbutamide (25 mg/kg: maximum 1 mg) intravenously (IV) and glucagon (0.03 mg/kg; maximum 1 mg) intramuscularly (IM) were given sequentially to 12 untreated girls with XO-Turner's syndrome (ages 6.5 to 17.0 years) and to ten female siblings (ages 8.0 to 16.7 years) to evaluate blood sugar (BS), plasma free fatty acids (FFA), serum immunoreactive insulin (IRI), and growth hormone (IRGH) responses to these insulinogenic secretagogues in order to appreciate any differences of genotypes on carbohydrate metabolism within identical family backgrounds. Seven of 12 patients with Turner's syndrome (58%) but none of the siblings were 20% or more overweight for height. There was a family history of diabetes mellitus in 7 to 12 patients (58%). The results showed significant elevations of mean FFA levels and decreased mean IRI responses to both insulinogenic stimuli without differences in mean BS or serum IRGH responses in the Turner's syndrome patients when compared to the controls. Three of 12 patients (25%) had abnormally elevated and prolonged blood sugar responses to IM glucagon. These findings show a significant incidence of abnormal carbohydrate and lipid metabolism and insulin deficiency in untreated patients with XO-Turner's syndrome when compared to normal female siblings and implicate this chromosomal defect in the impaired insulin secretion.

Glucagon suppression with low-dose intramuscular insulin therapy in diabetic ketoacidosis

The effects of low-dose intramuscular insulin therapy on endogenous glucagon secretion in diabetic ketoacidosis were compared prospectively with a conventional regimen. Ten patients, 4 to 15 years of age, who had 13 episodes of diabetic ketoacidosis, were alternately assigned to either group. Either 0.1 unit/kg regular insulin was given every two hours im, or 1.0 unit/kg regular insulin was given, half subcutaneously and half intravenously, every 4 hours. In both groups, a significant and equal fall in both serum glucose and glucagon concentrations was observed. No complications were encountered. It is concluded that 0.1 unit/kg of regular insulin given im every two hours is as effective in correcting hyperglycemia and hyperglucagonemia of diabetic ketoacidosis as is conventional therapy, and avoids the risks of secondary hypoglycemia known to occur when the larger insulin dosages are employed.