HESX1/Hesx1 is a member of the paired-like class of homeobox genes and is essential for pituitary and forebrain development. Mice with a targeted homozygous deletion of the Hesx1 show severe central nervous system defects, absence of optic vesicles, and a very small anterior pituitary gland. This phenotype is similar to the abnormalities observed in the human disorder called septo-optic dysplasia, a syndromic form of congenital hypopituitarism. To date, four missense mutations in the human HESX1 have been described in individuals with phenotypes ranging from severe septo-optic dysplasia, relatively mild combined pituitary hormone deficiency (CPHD), to isolated GH deficiency. Here we report a Japanese patient with CPHD (GH, TSH, LH, FSH, and ACTH deficiency) due to a novel sporadic HESX1 mutation. Brain magnetic resonance imaging examination revealed hypoplastic anterior pituitary, ectopic posterior lobe, and left optic nerve hypoplasia. Molecular analysis identified the insertion of a heterozygous mutation (306/307ins AG) in the exon 2 of the HESX1. This mutation changes a reading frame and introduces a premature stop codon soon after the mutation site. Therefore, this mutation would be predicted to generate a protein lacking the carboxyl-terminal homebox domain (DNA-binding domain) and cause the disease. Family analysis demonstrated that neither of the patient's parents harbored this mutation, indicating that the mutation had arisen de novo. In conclusion, a de novo heterozygous frameshift mutation in exon 2 of the HESX1 causes severe CPHD with optic nerve hypoplasia in a human.

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Abstract. LIM homeodomain transcription factors regulate many aspects of development in multicellular organisms. LHX4/Lhx4 is a protein that is essential for pituitary development and motor neuron specification in mammals. In human, a heterozygous splicing mutation of the LHX4 gene was reported in a family with combined pituitary hormone deficiencies (CPHD). In addition to CPHD, these patients were characterized by small sella turcica and chiari malformation. Here we report a Japanese patient with CPHD (GH, PRL, TSH, LH, FSH, and ACTH deficiency) due to a novel missense mutation (P366T) of the LHX 4 gene. She showed severe respiratory disease and hypoglycemia soon after birth. Brain MRI demonstrated hypoplastic anterior pituitary, ectopic posterior lobe, a poorly developed sella turcica, and chiari malformation. Sequence analysis of the LHX 4 gene identified a heterozygous missense mutation (P366T) in exon 6, which was present in LIM4 specific domain. Neither of the patient's parents harbored this mutation, indicating de novo mutation.

The cough sensitivity of patients with cough variant asthma is not necessarily identical to that of healthy individuals.

Abstract. Bartter syndrome (BS) type 1, also referred to antenatal BS, is a genetic tubulopathy with hypokalemic metabolic alkalosis and prenatal onset of polyuria leading to polyhydramnios. It has been shown that BS type 1 is caused by mutations in the SLC12A1 gene encoding bumetanide-sensitive Na-K-2Cl -cotransporter (NKCC2). We had the opportunity to care for two unrelated Japanese patients of BS type 1 with typical manifestations including polyhydramnios, prematurity, hypokalemia, alkalosis, and infantile-onset nephrocalcinosis. Analysis of the SLC12A1 gene demonstrated four novel mutations: N117X, G257S, D792fs and N984fs. N117X mutation is expected to abolish most of the NKCC2 protein, whereas G257, which is evolutionary conserved, resides in the third transmemebrane domain. The latter two frameshift mutations reside in the intra-cytoplasmic C-terminal domain, which illustrates the importance of this domain for the NKCC2 function. In conclusion, we found four novel SLC12A1 mutations in two BS type 1 patients. Development of effective therapy for hypercalciuria is mandatory to prevent nephrocalcinosis and resultant renal failure.