Megakaryocyte development is normal in mice with targeted disruption of Tescalcin.

BACKGROUND: Tescalcin is an EF-hand calcium-binding protein that interacts with the Na+/H+ exchanger 1 (NHE1). Levay and Slepak recently proposed a role for tescalcin in megakaryopoiesis that was independent of NHE1 activity. Their studies using K562 and HEL cell lines, and human CD34+ hematopoietic stem cells suggested an essential role for tescalcin in megakaryocyte differentiation. OBJECTIVE: To study the role of tescalcin in megakaryocyte development using a murine model of megakaryopoiesis. METHODS: We generated a mouse with targeted disruption of tescalcin and investigated megakaryocyte development. RESULTS: Tescalcin-deficient mice had a normal number of megakaryocytes and platelets. The morphology, polyploidization profile, and expression of Fli-1 in bone marrow-derived megakaryocytes were also normal. CONCLUSION: Tescalcin does not appear to be necessary for normal megakaryocyte development.

Duplication of SOX9 is not a common cause of 46,XX testicular or 46,XX ovotesticular DSD.

BACKGROUND: Translocation of the SRY gene to the paternal X chromosome is the explanation for testis development in the majority of subjects with 46,XX testicular disorder of sexual development (DSD). However, nearly all subjects with 46,XX ovotesticular DSD and up to one third of subjects with 46,XX testicular DSD lack SRY. SRY-independent expression of SOX9 has been implicated in the etiology of testis development in some individuals. METHODS: We amplified microsatellite markers in the region of SOX9 from a cohort of 30 subjects with either 46,XX testicular or 46,XX ovotesticular DSD to detect SOX9 duplications. RESULTS: Duplication of the SOX9 region in 17q was not detected in any subject. CONCLUSION: Duplication in the region of 17q that contains SOX9 is not a common cause of testis development in subjects with SRY-negative 46,XX testicular or ovotesticular DSD.

Expression and evolutionary conservation of the tescalcin gene during development.

The tescalcin gene (Tesc) encodes an EF-hand calcium-binding protein that interacts with the sodium/hydrogen exchanger, NHE1. Previous studies indicated that Tesc was expressed in mouse embryonic testis, but not in ovary, during the critical period of testis and ovary determination. In this paper we compared the expression of Tesc in embryonic tissues of chicken and mouse. Tesc expression was sexually dimorphic in the embryonic gonads of both mouse and chicken. Tescalcin (TESC) was detected in both Sertoli cells and germ cells. In the embryonic brain of both mouse and chicken, Tesc was highly expressed in the nasal placode and in fibers extending from the olfactory epithelium to the primordial olfactory bulb. Tesc was expressed in the embryonic heart of both chicken and mouse. In mouse Tesc expression was also detected in embryonic adrenal. These studies indicate very specific expression of Tesc in various tissues in chicken and mouse during embryologic development, and conservation of Tesc expression in both species.

A nine year old girl with thyrotoxicosis, ataxia, and chorea.

Neurologic manifestations are common in patients with thyroid disease. We describe the case of a nine year old girl with Graves disease and the unique combination of chorea and ataxia that both resolved after treatment of hyperthyroidism.

Madelung-like deformity in pseudohypoparathyroidism type 1b.

CONTEXT: Pseudohypoparathyroidism (PHP) types 1a and 1b are distinguished by clinical, biochemical, and molecular features. We report extended kindred with PHP 1b in which many affected members also had growth plate defects, including brachydactyly and a Madelung-like deformity. DESIGN: Analyses included clinical examination, assessment of mineral metabolism, thyroid function, skeletal radiography, and analysis of the GNAS and STX16 genes. SETTING: Patients were studied in an academic medical center. RESULTS: We studied 37 members of a family in which PHP 1b occurred in 23 individuals. Ten of 17 affected patients who were examined had brachydactyly E, including two subjects with Madelung-like defects. Five of 16 subjects had subclinical hypothyroidism; no subject showed sc ossification or short stature. None of the unaffected members had brachydactyly or an elevated serum level of PTH or TSH. Levels of immunoactive erythrocyte Gα(s) were normal in two affected subjects tested. Linkage analysis indicated linkage between PTH resistance and the GNAS gene locus; however, no mutations were identified in GNAS exons 1-13. Methylation analysis of genomic DNA from affected subjects showed loss of maternal epigenotype in exon 1A with normal methylation of the differentially methylated regions for XLGαs and NESP55, and PCR demonstrated heterozygosity for a 3.0-kb deletion in the STX16 gene. CONCLUSION: The segregation of brachydactyly with PHP 1b in this family indicates that an imprinting defect in GNAS can lead to growth plate defects, including brachydactyly and Madelung deformity. These features suggest that GNAS signaling plays a more extensive role in chondrocyte maturation than previously thought.

46,XX sex reversal with partial duplication of chromosome arm 22q.

We present a case of 46,XX sex reversal in the absence of SRY but with partial duplication of chromosome 22q. The subject had multiple congenital anomalies but nearly complete masculinization of the external genitalia. Our case along with a previous case supports the existence of a gene on chromosome 22q that can trigger testis determination in the absence of SRY. We proposed that overexpression of the SOX10 gene at 22q13 might be the cause of sex reversal. We investigated 13 additional subjects with SRY-negative 46,XX sex reversal for microduplication of chromosome arm 22q in the region of SOX10 gene, but could not find evidence for it.

46,XY intersex individuals: phenotypic and etiologic classification, knowledge of condition, and satisfaction with knowledge in adulthood.

OBJECTIVES: The objective of this study was to identify and study adults who have a 46,XY karyotype and presented as infants or children with variable degrees of undermasculinization of their genitalia (female genitalia, ambiguous genitalia, or micropenis). Participants' knowledge of their condition, satisfaction with their knowledge, and desire for additional education about their intersex condition were assessed. METHODS: Participants were classified according to the cause underlying their intersex condition based on review of medical and surgical records. Knowledge of medical condition, satisfaction with that knowledge, and desire for additional education were assessed with a written questionnaire and a semistructured interview. RESULTS: Patients were ineligible for recruitment because of death (9%), because of developmental delay (12%), or because they were not located (27%). Among the 96 eligible patients, 78% participated. Approximately half of the men (53%) and women (54%) exhibited a good understanding of their history. Fewer women who have a 46,XY chromosome complement and were born with female genitalia were informed about their intersex condition (36% with complete androgen insensitivity syndrome) than were women who were born with masculinized genitalia such as micropenis (80%) or ambiguous genitalia (72%). More women (66%) than men (38%) were satisfied with their knowledge of their medical and surgical history. CONCLUSIONS: Almost half of the patients, reared male or female, were neither well informed about their medical and surgical history nor satisfied with their knowledge.

Characterization of tescalcin, a novel EF-hand protein with a single Ca2+-binding site: metal-binding properties, localization in tissues and cells, and effect on calcineurin.

The tescalcin gene is preferentially expressed during mouse testis differentiation. Here, we demonstrate that this gene encodes a 24 kDa Ca(2+)- and Mg(2+)-binding protein with one consensus EF-hand and three additional domains with EF-hand homology. Equilibrium dialysis with (45)Ca(2+) revealed that recombinant tescalcin binds approximately one Ca(2+) ion at physiological concentrations (pCa 4.5). The intrinsic tryptophan fluorescence of tescalcin was significantly reduced by Ca(2+), indicative of a conformational change. The apparent K(d) for Ca(2+) was 0.8 microM. A point mutation in the consensus EF-hand (D123A) abolished (45)Ca(2+) binding and prevented the fluorescence quenching, demonstrating that the consensus EF-hand alone mediates the Ca(2+)-induced conformational change. Tescalcin also binds Mg(2+) (K(d) 73 microM), resulting in a much smaller fluorescence decrease. In the presence of 1 mM Mg(2+), tescalcin's Ca(2+) affinity is shifted to 3.5 microM. These results illustrate that tescalcin should bind Mg(2+) constitutively in a quiescent cell, replacing it with Ca(2+) during stimulation. We also show that tescalcin is most abundant in adult mouse heart, brain, and stomach, as well as in HeLa and HL-60 cells. Immunofluorescence microscopy revealed that tescalcin is present in the cytoplasm and nucleus, with concentration in membrane ruffles and lamellipodia in the presence of serum, where it colocalizes with the small guanosine triphosphatase Rac-1. Tescalcin shares sequence and functional homology with calcineurin-B homologous protein (CHP), and we found that tescalcin, like CHP, can inhibit the phosphatase activity of calcineurin A. Hence, tescalcin is a novel calcineurin B-like protein that binds a single Ca(2+) ion.

Ambiguous genitalia with perineoscrotal hypospadias in 46,XY individuals: long-term medical, surgical, and psychosexual outcome.

OBJECTIVES: To identify and study adults (21 years or older) who have a 46,XY karyotype and presented as infants or children with genital ambiguity, including a small phallus and perineoscrotal hypospadias, reared male or female. METHODS: Participants were classified according to the cause underlying their intersex condition based on review of medical and surgical records. Long-term medical and surgical outcome was assessed with a written questionnaire and physical examination. Long-term psychosexual development was assessed with a written questionnaire and semistructured interview. RESULTS: Thirty-nine (72%) of 54 eligible patients participated. The cause underlying genital ambiguity of participants included partial androgen insensitivity syndrome (n = 14; 5 men and 9 women), partial gonadal dysgenesis (n = 11; 7 men and 4 women), and other intersex conditions. Men had significantly more genital surgeries (mean: 5.8) than women (mean: 2.1), and physician-rated cosmetic appearance of the genitalia was significantly worse for men than for women. The majority of participants were satisfied with their body image, and men and women did not differ on this measure. Most men (90%) and women (83%) had sexual experience with a partner. Men and women did not differ in their satisfaction with their sexual function. The majority of participants were exclusively heterosexual, and men considered themselves to be masculine and women considered themselves to be feminine. Finally, 23% of participants (5 men and 4 women) were dissatisfied with their sex of rearing determined by their parents and physicians. CONCLUSIONS: Either male or female sex of rearing can lead to successful long-term outcome for the majority of cases of severe genital ambiguity in 46,XY individuals. We discuss factors that should be considered by parents and physicians when deciding on a sex of rearing for such infants.