Hiroko Yagi

Fertility preservation in a family with a novel NR5A1 mutation.

The common phenotype of nuclear receptor superfamily 5, group A, member 1 (NR5A1) gene mutations in 46,XY is gonadal dysgenesis without adrenal deficiency. Though the phenotype of gonadal dysgenesis is variable, ranging from complete female to normal male genitalia, an asymptomatic 46,XY male is rare. Preserved fertility has so far been described in only three affected 46,XY males with different mutations, but no functional analysis of these mutations has been performed. Here, we report on male siblings with hypospadias and their asymptomatic father in whom we identified a heterozygous NR5A1 mutation of c.910G>A, p.E304K. Western blotting and subcellular localization revealed no significant difference between the wild type (WT) and E304K. Electrophoretic mobility shift assay experiments showed that E304K abrogated DNA-binding ability. E304K reduced transactivation and had no dominant negative effect. In conclusion, we report on a novel hypomorphic NR5A1 mutation, which may be associated with the phenotype of the family.

Syndromic disorder of sex development due to a novel hemizygous mutation in the carboxyl-terminal domain of ATRX

Alpha-thalassemia/mental retardation syndrome X-linked (ATRX; OMIM #301040), which is caused by mutations in the ATRX gene, is characterized by alpha-thalassemia, distinct dysmorphic facies, psychomotor development delay and genital abnormalities. Here, we describe a neonatal case of syndromic disorder of sex development, harboring a novel hemizygous mutation, p.Asp2352fs*1 in the carboxyl-terminal domain of ATRX. Our study provides additional evidence that deletion of the carboxyl terminus of ATRX is associated with severe genital anomalies.

A novel heterozygous intronic mutation in POU1F1 is associated with combined pituitary hormone deficiency

POU class 1 homeobox 1 (POU1F1) regulates pituitary cell-specific gene expression of somatotropes, lactotropes, and thyrotropes. In humans, two POU1F1 isoforms (long and short isoform), which are generated by the alternative use of the splice acceptor site for exon 2, have been identified. To date, more than 30 POU1F1 mutations in patients with combined pituitary hormone deficiency (CPHD) have been described. All POU1F1 variants reported to date affect both the short and long isoforms of the POU1F1 protein; therefore, it is unclear at present whether a decrease in the function of only one of these two isoforms is sufficient for disease onset in humans. Here, we described a sibling case of CPHD carrying a heterozygous mutation in intron 1 of POU1F1. In vitro experiments showed that this mutation resulted in exon 2-skipping of only in the short isoform of POU1F1, while the long isoform remained intact. This result strongly suggests the possibility, for the first time, that isolated mutations in the short isoform of POU1F1 could be sufficient for induction of POU1F1-related CPHD. This finding improves our understanding of the molecular mechanisms, and developmental course associated with mutations in POU1F1.

Functional Characterization of c.870+3_6delGAGT Splice Site Mutation in NR5A1

Background: To date, more than 100 mutations of NR5A1 have been reported; however, mutations affecting the splice site are rare, with only two reported mutations. Objective: To characterize the c.870+3_6delGAGT splice mutation of NR5A1 through molecular analyses. Results: The reverse transcription polymerase chain reaction (RT-PCR) study revealed that c.870+3_6delGAGT resulted in p.A82fs*95. Mutant NR5A1 showed a reduced transactivation on the CYP11A1 and STAR promoters without a dominant negative effect. Conclusion: To the best of our knowledge, this is the first report of the NR5A1 splice site mutation, which was proven to be deleterious by the RT-PCR method.

A familial case of spondyloepiphyseal dysplasia tarda caused by a novel splice site mutation in TRAPPC2

Mami Fukuma1, Masaki Takagi2, Tomoyuki Shimazu1, Hoseki Imamura1, Hiroko Yagi3,4, Gen Nishimura5, and Tomonobu Hasegawa2 1 Department of Pediatrics, Kumamoto Saishunso National Hospital, Kumamoto, Japan 2 Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan 3 Department of Endocrinology and Metabolism, Tokyo Metropolitan Children’s Medical Center, Tokyo, Japan 4 Department of Pediatrics, Hirosaki University Graduate School of Medicine, Aomori, Japan 5 Center for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan

Gradually increasing ethinyl estradiol for Turner syndrome may produce good final height but not ideal BMD

Estrogen replacement therapy in Turner syndrome should theoretically mimic the physiology of healthy girls. The objective of this study was to describe final height and bone mineral density (BMD) in a group of 17 Turner syndrome patients (group E) who started their ethinyl estradiol therapy with an ultra-low dosage (1-5 ng/kg/day) from 9.8-13.7 years. The subjects in group E had been treated with GH 0.35 mg/kg/week since the average age of 7.4 years. The 30 subjects in group L, one of the historical groups, were given comparable doses of GH, and conjugated estrogen 0.3125 mg/week ∼0.3125 mg/day was initiated at 12.2-18.7 years. The subjects in group S, the other historical group, were 21 patients who experienced breast development and menarche spontaneously. Final height (height gain < 2 cm/year) in group E was 152.4 ± 3.4 cm and the standard deviation (SD) was 2.02 ± 0.62 for Turner syndrome. The final height in group L was 148.5 ± 3.0 cm with a SD of 1.30 ± 0.55, which was significantly different from the values for group E. The volumetric BMD of group S (0.290 ± 0.026 g/cm3) was significantly different from that of group L or E (0.262 or 0.262 g/cm3 as a mean, respectively). This is the first study of patients with Turner syndrome where estrogen was administered initially in an ultra-low dose and then increased gradually. Our estrogen therapy in group E produced good final height but not ideal BMD.

Novel heterozygous mutation in the extracellular domain of FGFR1 associated with Hartsfield syndrome.

Heterozygous kinase domain mutations or homozygous extracellular domain mutations in FGFR1 have been reported to cause Hartsfield syndrome (HS), which is characterized by the triad of holoprosencephaly, ectrodactyly and cleft lip/palate. To date, more than 200 mutations in FGFR1 have been described; however, only 10 HS-associated mutations have been reported thus far. We describe a case of typical HS with hypogonadotropic hypogonadism (HH) harboring a novel heterozygous mutation, p.His253Pro, in the extracellular domain of FGFR1. This is the first report of an HS-associated heterozygous mutation located in the extracellular domain of FGFR1, thus expanding our understanding of the phenotypic features and further developmental course associated with FGFR1 mutations.

Early-onset urological disorders due to Wolfram syndrome: A case of neonatal onset

Wolfram syndrome (WS) is an autosomal recessive neurodegenerative disorder characterized by DIDMOAD (diabetes insipidus, diabetes mellitus, optic atrophy, and deafness). Genetic analysis has demonstrated mutations of the WOLFRAMIN gene (WFS1) in patients with this syndrome (1), which may be complicated by other conditions, among them urological disorders (UDs). According to one study, UDs were found to occur in 19.39% (76/392) of WS patients with an average age of 20 yr (2), with only two patients presenting UDs before the age of 5 yr, both during infancy. We report here a neonatal case of WS presenting UDs.

A case of spondyloepiphyseal dysplasia tarda caused by a novel intragenic deletion of TRAPPC2.

Spondyloepiphyseal dysplasia tarda (SEDT; MIM # 313400) is a rare X-linked recessive skeletal disease characterized by disproportionate short stature with vertebral malformation and degenerative changes involving the spine and major joints (1). During infancy and early childhood, affected males show normal development and unremarkable findings on radiographs (1). Clinical expression of SEDT begins with a flattening of the growth curve before puberty. At this time, radiographs show characteristic deformities of the vertebrae, including platyspondyly with a posterior hump. Degenerative joint disease is a common problem in male patients making hip joint replacement often necessary in the fourth or fifth decade of life (2). The causative gene of SEDT is TRAPPC2, which encodes trafficking protein particle complex subunit 2, a 140 amino acid protein, also known as Sedlin. TRAPPC2 may play a role in vesicular transport from the endoplasmic reticulum to the Golgi (3, 4). To date, 50 TRAPPC2 mutations have been reported in families with SEDT of different ethnic origin (Human Gene Mutation Database; http://www.hgmd.cf.ac.uk/ac). The underlying mutations are spread over the entire coding region of the TRAPPC2 gene comprising exons 3-6, without clear genotype-phenotype correlation. Here, we report a Japanese SEDT patient with a novel intragenic deletion mutation in TRAPPC2.

A case of a Japanese patient with neonatal diabetes mellitus caused by a novel mutation in the ABCC8 gene and successfully controlled with oral glibenclamide.

Permanent neonatal diabetes mellitus (PNDM) is a rare form of insulin-dependent diabetes mellitus that presents within the first 6 months after birth and may require lifelong insulin treatment. Approximately 40% of all PNDM cases are caused by activating mutations in either the KCNJ11 gene or ABCC8 gene, which encode the Kir6.2 or sulfonylurea receptor (SUR) 1 subunit of the ATP-sensitive potassium channel (KATP channel), respectively (1,2,3). The KATP channel is expressed on the surface of pancreatic beta cells. In this context, a heterozygous gain-of-function mutation in ABCC8 or KCNJ11 causes PNDM. High-dose oral sulfonylurea has been reported to be an effective treatment agent for PNDM with ABCC8 and KCNJ11 gene mutations compared with insulin injection (4). Here we report a patient with PNDM caused by a novel heterozygous missense mutation in ABCC8 and controlled with oral glibenclamide for more than 3 yr.