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1/6. A particular phenotype in a girl with aldosterone synthase deficiency.

    aldosterone synthase deficiency (ASD) usually presents in infancy as a life-threatening electrolyte imbalance. A 4-wk-old child of unrelated parents was examined for failure to thrive and salt-wasting. Notable laboratory findings were hyperkalemia, high plasma renin, and low-normal aldosterone levels. Urinary metabolite ratios of corticosterone/18-hydroxycorticosterone and 18-hydroxycorticosterone/aldosterone were intermediate between ASD type I and type II. sequence analysis of CYP11B2, the gene encoding aldosterone synthase (P450c11AS), revealed that the patient was a compound heterozygote carrying a previously described mutation located in exon 4 causing a premature stop codon (E255X) and a further, novel mutation in exon 5 that also causes a premature stop codon (Q272X). The patient's unaffected father was a heterozygous carrier of the E255X mutation, whereas the unaffected mother was a heterozygous carrier of the Q272X mutation. Therefore, the patient's CYP11B2 encodes two truncated forms of aldosterone synthase predicted to be inactive because they lack critical active site residues as well as the heme-binding site. This case of ASD is of particular interest because despite the apparent lack of aldosterone synthase activity, the patient displays low-normal aldosterone levels, thus raising the question of its source. ( info)

2/6. estrogens are essential for male pubertal periosteal bone expansion.

    The skeletal response to estrogen therapy was studied in a 17-yr-old boy with congenital aromatase deficiency. As expected, estrogen therapy (1 mg estradiol valeriate/d from age 17 until 20 yr) normalized total and free testosterone and reduced the rate of bone remodeling. Dual-energy x-ray absorptiometry-assessed areal bone mineral density (BMD) of the lumbar spine and femoral neck increased significantly (by 23% and 14%, respectively), but peripheral quantitative computed tomography at the ultradistal radius revealed no gain of either trabecular or cortical volumetric BMD. The increase in areal BMD was thus driven by an increase in bone size. Indeed, longitudinal bone growth (height, 8.5%) and especially cross-sectional area of the radius ( 46%) and cortical thickness ( 12%), as measured by peripheral quantitative computed tomography, increased markedly during estrogen treatment. These findings demonstrate that androgens alone are insufficient, whereas estrogens are essential for the process of pubertal periosteal bone expansion typically associated with the male bone phenotype. ( info)

3/6. A male twin infant with skull deformity and elevated neonatal 17-hydroxyprogesterone: a prismatic case of P450 oxidoreductase deficiency.

    We report on a male twin infant who presented with brachy-turri-cephaly, frontal bossing, large anterior fontanelle, low set and malformed ears, and mild arachnodactyly. He had normal male genitalia. There was no evidence for maternal virilization during pregnancy. The pattern of malformations resembled Antley-Bixler-syndrome (ABS). However, sequencing analysis of the fibroblast growth factor receptor 2 gene (FGFR2) did not reveal mutations. The boy's twin sister did not show any somatic or endocrine abnormalities. In the boy, neonatal screening for congenital adrenal hyperplasia was positive with moderately elevated 17-hydroxyprogesterone. sequence analysis of his CYP21 gene did not reveal any mutations. The short synacthen test revealed an exaggerated 17-hydroxyprogesterone and a blunted cortisol response. Urinary steroid profiling by gas chromatography-mass spectrometry (GC-MS) revealed a unique steroid metabolome suggestive of impaired activity of both 17-hydroxylase and 21-hydroxylase. Clinical and metabolic findings therefore were compatible with the recently described variant of congenital adrenal hyperplasia, P450 oxidoreductase deficiency (ORD). Subsequently, sequencing analysis of CPR, the gene encoding P450 oxidoreductase (OR), revealed a homozygous mutation in the patient, resulting in an amino acid exchange in position 284 of the OR protein (A284P). Both the female twin sister and the parents were heterozygous for the A284P mutation. P450 oxidoreductase deficiency represents a novel autosomal recessively inherited form of congenital adrenal hyperplasia. Its characteristic steroid metabolome can readily be detected by GC-MS analysis of spot urine. Clinical features may include an ABS phenotype, ambiguous genitalia (virilization in girls, feminization in boys), and glucocorticoid deficiency. If required, hydrocortisone replacement should be provided. ( info)

4/6. hypertension in a patient with aldosterone deficiency.

    OBJECTIVE: To describe a patient with aldosterone synthase deficiency, who presented with failure to thrive, hypovolemic hyponatremia, and the unexpected finding of hypertension. methods: We present a case report, review the related literature, and outline a possible mechanism for the concomitant occurrence of high blood pressure and hyponatremia in this patient. RESULTS: A 5-month-old infant with unambiguous female genitalia was admitted to our hospital with failure to thrive and hyponatremia. Her blood pressure was 115/88 mm Hg (>95% for age). The serum sodium concentration was 123 mEq/L (normal for age, >130), and the potassium level was 5.3 mEq/L (normal, 3.5 to 5.3). A direct renin measurement by immunochemiluminescence assay was 11,400 microU/mL (normal, <5), and the aldosterone level was 4 ng/dL (normal, 2 to 70). These findings indicated a diagnosis of aldosterone synthase deficiency. Treatment with fludrocortisone and sodium chloride was begun, but the hypertension worsened. Therapy with an angiotensin-converting enzyme inhibitor was transiently required. CONCLUSION: angiotensin ii, a potent vasoconstrictor, is an intermediate in the renin-angiotensin system. We believe that this protein was the cause of the hypertension in the setting of aldosterone deficiency in our patient. ( info)

5/6. Compound heterozygosity of a frameshift mutation in the coding region and a single base substitution in the promoter of the ACTH receptor gene in a family with isolated glucocorticoid deficiency.

    Isolated glucocorticoid deficiency (IGD) is an autosomal recessive syndrome characterized by glucocorticoid insufficiency without mineralocorticoid deficiency. Mutations in the coding region of the ACTH receptor (MC2R) have been reported in several families with IGD. We amplified and sequenced the entire MC2R coding region in a new family with IGD. The proband was found to be heterozygous (paternal allele) for the mutation Gly217fs, which changes the open reading frame of the MC2R protein resulting in a truncated receptor. No other abnormality was found in the MC2R coding region. However, sequencing of the promoter region of the MC2R gene (-1017/44 bp) of the proband revealed a heterozygous T-->C substitution in the maternal allele at -2 bp position from initiation of the transcription start site. This substitution was found in only 6.5% in a healthy unrelated population. Constructs containing this polymorphism consistently showed a significant 15% decrease in promoter activity compared to wild type. In conclusion, we provide evidence that the IGD in this previously unreported family with ACTH resistance appears to be secondary to compound heterozygosity of a coding region and a promoter mutation in the MC2R gene. ( info)

6/6. Novel compound heterozygous mutation of the MC2R gene in a patient with familial glucocorticoid deficiency.

    Familial glucocorticoid deficiency (FGD) is an autosomal recessive disorder characterised by glucocorticoid insufficiency without mineralocorticoid deficiency. Here, we report a 2 year-old girl with FGD, showing tall stature and skin pigmentation, but no abnormalities of the external genitalia. serum sodium, potassium and chloride levels were within normal ranges. Endocrinological analysis revealed low serum cortisol (<5.5 nmol/1), elevated plasma ACTH (875.2 pmol/1) and low 17alpha-hydroxyprogesterone (< 0.303 nmol/l). We suspected the patient of having FGD type 1. Direct and allele-specific sequence analyses of the melanocortin 2 receptor gene (MC2R) revealed compound heterozygous mutations (C21Y and R146H) in the MC2R gene. Her father and mother each had heterozygous C21Y and R146H mutations, respectively, without symptoms of glucocorticoid deficiency. This is the first report of FGD associated with a compound heterozygous mutation of C21Y and R146H in the MC2R gene. ( info)

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