Identification of the first promoter-specific gain-of-function SOX9 missense variant (p.E50K) in a patient with 46,XX ovotesticular disorder of sex development.

SOX9, a transcription factor, is expressed in the undifferentiated XX and XY gonads. SRY induces significant upregulation of SOX9 expression in XY gonads. Loss-of-function SOX9 variants cause testicular dysgenesis in 46,XY patients, while duplication of the total gene or the upstream regulatory region results in testicular development in 46,XX patients. However, gain-of-function (GoF) SOX9 variants have not been reported previously. We report the case of a 16-year-old female patient with a 46,XX karyotype who had masculinized external genitalia and unilateral ovotestis. Next-generation sequencing-based genetic screening for disorders of sex development led to the identification of a novel SOX9 variant (p.Glu50Lys), transmitted from the phenotypically normal father. Expression analysis showed that E50K-SOX9 enhanced transactivation of the luciferase reporter containing the testis enhancer sequence core element compared with that containing the wildtype-SOX9. This GoF activity was not observed in the luciferase reporter containing Amh, the gene for anti-Müllerian hormone. We genetically engineered female mice (Sox9E50K/E50K ), and they showed no abnormalities in the external genitalia or ovaries. In conclusion, a novel SOX9 variant with a promoter-specific GoF activity was identified in vitro; however, the disease phenotype was not recapitulated by the mouse model. At present, the association between the GoF SOX9 variant and the ovotestis phenotype remains unclear. Future studies are needed to verify the possible association.

MIRAGE syndrome is a rare cause of 46,XY DSD born SGA without adrenal insufficiency.

BACKGROUND: MIRAGE syndrome, a congenital multisystem disorder due to pathogenic SAMD9 variants, describes a constellation of clinical features including 46,XY disorders of sex development (DSD), small for gestational age (SGA) and adrenal insufficiency (AI). It is poorly understood whether SAMD9 variants underlie 46,XY DSD patients born SGA (46,XY DSD SGA) without AI. This study aimed to define the frequency and phenotype of SAMD9 variants in 46,XY DSD SGA without AI. METHODS: Forty-nine Japanese patients with 46,XY DSD SGA (Quigley scale, 2 to 6; gestational age-matched birth weight percentile, <10) without history of AI were enrolled. The single coding exon of SAMD9 was PCR-amplified and sequenced for each patient. Pathogenicity of an identified variant was verified in vitro. Placenta tissues were obtained from the variant-carrying patient, as well as from another previously described patient, and were analyzed histologically. RESULTS: In one 46,XY DSD SGA patient, a novel heterozygous SAMD9 variant, p.Phe1017Val, was identified. Pathogenicity of the mutant was experimentally confirmed. In addition to DSD and SGA, the patient had neonatal thrombocytopenia, severe postnatal grow restriction, chronic diarrhea and susceptibility to infection, all features consistent with MIRAGE, leading to premature death at age 14 months. The patient did not have any manifestations or laboratory findings suggesting AI. Placenta tissues of the two variant-carrying patients were characterized by maldevelopment of distal villi without other findings of maternal underperfusion. CONCLUSIONS: MIRAGE syndrome is a rare cause of 46,XY DSD SGA without AI. This study exemplifies that AI is a common feature of MIRAGE syndrome but that the absence of AI should not rule out a diagnosis of the syndrome.

Genetic defects in pediatric-onset adrenal insufficiency in Japan.

CONTEXT: Most patients with pediatric-onset primary adrenal insufficiency (PAI), such as 21-hydroxylase deficiency, can be diagnosed by measuring the urine or serum levels of steroid metabolites. However, the etiology is often difficult to determine in a subset of patients lacking characteristic biochemical findings. OBJECTIVE: To assess the frequency of genetic defects in Japanese children with biochemically uncharacterized PAI and characterize the phenotypes of mutation-carrying patients. METHODS: We enrolled 63 Japanese children (59 families) with biochemically uncharacterized PAI, and sequenced 12 PAI-associated genes. The pathogenicities of rare variants were assessed based on in silico analyses and structural modeling. We calculated the proportion of mutation-carrying patients according to demographic characteristics. RESULTS: We identified genetic defects in 50 (85%) families: STAR in 19, NR0B1 in 18, SAMD9 in seven, AAAS in two, NNT in two, MC2R in one and CDKN1C in one. NR0B1 defects were identified in 78% of the male patients that received both glucocorticoid and mineralocorticoid replacement therapy and had normal male external genitalia. STAR defects were identified in 67% of female and 9% of male patients. Seven of the 19 patients with STAR defects developed PAI at age two or older, out of whom, five did not have mineralocorticoid deficiency. CONCLUSIONS: Molecular testing elucidated the etiologies of most biochemically uncharacterized PAI patients. Genetic defects such as NR0B1 defects are presumed based on phenotypes, while others with broad phenotypic variability, such as STAR defects, are difficult to diagnose. Molecular testing is a rational approach to diagnosis in biochemically uncharacterized PAI patients.

Genetic studies on reference strains of mutans streptococci.

Twenty four reference strains (serotype a-h) belonging to the mutans group of streptococci were compared for DNA fragment patterns of rDNA after treatment with Hind III. It was shown that Streptococcus cricetus (serotype a), S. rattus (serotype b), and S. downei (serotype h) reveals comparatively homogeneous patterns while S. mutans (serotype c, e and f) exhibits differences between the different serotypes as well as within single serotypes. S. sobrinus had an intermediary diversity. These data support the previous findings that S. mutans is heterogeneous at the serological, biochemical and genetical level.

The effect of intramuscular testosterone enanthate treatment on stretched penile length in prepubertal boys with hypospadias.

OBJECTIVES: To define the responses of stretched penile length (PL) to intramuscular testosterone enanthate (TE) treatment in prepubertal boys with hypospadias. METHODS: We examined 17 Japanese boys with hypospadias at 1.4 +/- 1.3 (mean +/- SD) years of age. Their PLs were 2.79 +/- 0.37 cm and -1.16 +/- 0.88 SD of the mean. The etiology of hypospadias included sex chromosome disorders of sex development in 5, mastermind-like domain-containing 1 deficiency in 1, and unknown cause in the others. No mutation was identified in the SRD5A2 or AR gene. All the boys received as many as three intramuscular injections of TE 25 mg every 4 weeks (one injection in 3 boys, two in 5, and three in 9). RESULTS: The TE treatment significantly increased PL by 1.01 +/- 0.50 cm and 2.27 +/- 0.99 SD (cm, P = .0002; SD, P = .0002). Age, body surface area (BSA), and PL before the treatment did not significantly correlate with the effect of TE treatment on PL. The effect of TE treatment on PL at the first injection in Japanese boys with hypospadias (0.35 +/- 0.20 cm and 0.91 +/- 0.62 SD) was significantly less than that in micropenis at 2.6 +/- 3.1 years of age (0.64 +/- 0.26 cm and 1.37 +/- 0.68 SD) (cm, P = .0008; SD, P = .02). CONCLUSIONS: These data indicate that (1) the intramuscular TE treatment significantly increases PL for hypospadias in prepubertal boys, with no demonstrable SRD5A2 or AR mutation; (2) age, BSA, and PL before the treatment are not significantly contributing factors to the effect of TE treatment; and (3) the effect of TE treatment for hypospadias is significantly less than that for micropenis.