Next generation sequencing-based mutation screening of 86 patients with idiopathic short stature.

Although mutations in ACAN, FGFR3, NPR2, and SHOX typically lead to skeletal dysplasia, and mutations in GHRHR, GH1, GHR, STAT5B, IGF1, IGFALS, and IGF1R usually underlie hormonal defects of the growth hormone (GH)-insulin-like growth factor 1 (IGF1) axis, such mutations have also been identified in patients with idiopathic short stature (ISS). Of these, SHOX abnormalities are known to account for a certain percentage of ISS cases, whereas the frequency of mutations in the other 10 genes in ISS cohorts remains unknown. Here, we performed next-generation sequencing-based mutation screening of the 10 genes in 86 unrelated Japanese ISS patients without SHOX abnormalities. We searched for rare protein-altering variants. The functional significance of the identified variants was assessed by in silico analyses. Consequently, we identified 18 heterozygous rare variants in 19 patients, including four probable damaging variants in ACAN, six pathogenicity-unknown variants in FGFR3, GHRHR, GHR, and IGFALS, and eight possible benign variants. Pathogenic variants in NPR2, GH1, and IGF1 were absent from our cohort. Unlike previously reported patients with ACAN mutations, our four patients with ACAN variants manifested non-specific short stature with age-appropriate or mildly delayed bone ages, and had parents of normal stature. These results indicate that ACAN mutations can underlie ISS without characteristic skeletal features, and that such mutations are possibly associated with de novo occurrence or low penetrance. In addition, our data imply that mutations in FGFR3, NPR2, and GH-IGF1 axis genes play only limited roles in the etiology of ISS.

A case report and literature review of monoallelic mutation of GHR.

Background Monoallelic mutations of GHR have been described in idiopathic short stature (ISS), although the significance of these remain unclear. We report a case of ISS with novel monoallelic S219L mutation of GHR and discuss the possible significance of monoallelic GHR mutation in ISS. Case presentation The proband, a 13.9-year-old Japanese boy, had severe short stature (-3.8 standard deviation [SD]). Serum insulin-like growth factor (IGF)-I level and growth hormone (GH) secretion was normal. His parents were nonconsanguineous and had normal stature. Genetic analyses revealed a novel monoallelic missense variation in exon 7 of GHR (S219L). The proband's mother had the same variation. S219L might be the novel mutation judging from there being no registration of it as a single-nucleotide polymorphism (SNP) in any database, evolutional conservation of Ser219, in silico analyses, and computational molecular visualization analysis. Furthermore, a review of the literature showed that the median height of missense mutation carriers of GHR was relatively low. Conclusions We propose the possibility that monoallelic mutation of GHR increases the susceptibility to short stature.

A patient with pseudohypoaldosteronism type II complicated by congenital hypopituitarism carrying a KLHL3 mutation.

Pseudohypoaldosteronism type II (PHA II) is a renal tubular disease that causes hyperkalemia, hypertension, and metabolic acidosis. Mutations in four genes (WNK4, WNK1, KLHL3, and CUL3) are known to cause PHA II. We report a patient with PHA II carrying a KLHL3 mutation, who also had congenital hypopituitarism. The patient, a 3-yr-old boy, experienced loss of consciousness at age 10 mo. He exhibited growth failure, hypertension, hyperkalemia, and metabolic acidosis. We diagnosed him as having PHA II because he had low plasma renin activity with normal plasma aldosterone level and a low transtubular potassium gradient. Further investigations revealed defective secretion of GH and gonadotropins and anterior pituitary gland hypoplasia. Genetic analyses revealed a previously known heterozygous KLHL3 mutation (p.Leu387Pro), but no mutation was detected in 27 genes associated with congenital hypopituitarism. He was treated with sodium restriction and recombinant human GH, which normalized growth velocity. This is the first report of a molecularly confirmed patient with PHA II complicated by congenital hypopituitarism. We speculate that both GH deficiency and metabolic acidosis contributed to growth failure. Endocrinological investigations will help to individualize the treatment of patients with PHA II presenting with growth failure.

Kinetics and products of reactions of MTBE with ozone and ozone/hydrogen peroxide in water.

Methyl-t-butyl-ether (MTBE) has become a prevalent groundwater pollutant due to its high volume use as a nationwide gasoline additive. Given its physicochemical properties, it requires new treatment approaches. Both aqueous O(3) and a combination of O(3)/H(2)O(2), which gives *OH, can remove MTBE from water, making use of O(3) a viable technology for remediation of groundwater from fuel contaminated sites. Rate constants and temperature dependencies for reactions of MTBE with O(3) or with *OH at pH 7.2, in a range of 21-45 degrees C (294-318K) were measured. The second-order rate constant for reaction of MTBE with O(3) is 1.4 x 10(18)exp(-95.4/RT) (M(-1)s(-1)), and for reaction of MTBE with *OH produced by the combination of O(3)/H(2)O(2) is 8.0 x 10(9)exp(-4.6/RT) (M(-1)s(-1)), with the activation energy (kJ mol(-1)) in both cases. At 25 degrees C, this corresponds to a rate constant of 27 M(-1)s(-1) for ozone alone, and 1.2 x 10(9) M(-1)s(-1) for O(3)/H(2)O(2). The concentration of *OH was determined using benzene trapping. Products of reactions of O(3) and O(3)/H(2)O(2) with MTBE, including t-butyl-formate (TBF), t-butyl alcohol (TBA), methyl acetate, and acetone, were determined after oxidant depletion. A reaction pathway for mineralization of MTBE was also explored. Under continuously stirred flow reactor (CSTR) conditions, addition of H(2)O(2) markedly increases the rate and degree of degradation of MTBE by O(3).