Short stature in children with an apparently normal male phenotype can be caused by 45,X/46,XY mosaicism and is susceptible to growth hormone treatment

Girls with unexplained short stature are routinely screened for the presence of Ullrich-Turner syndrome by clinical examination, laboratory tests, and karyotyping. In this study, we performed chromosomal analysis in boys to explore the role of 45,X/46,XY mosaicism for short stature in males. Short-term effects of growth hormone treatment in male 45,X/46,XY individuals were compared retrospectively to those in female patients. We report six boys with a normal-appearing male phenotype and 45,X/46,XY mosaicism, four of whom were diagnosed postnatally because of short stature. Two boys were diagnosed prenatally by amniocentesis. Five boys were short and were treated with growth hormone (0.04–0.05 mg/kg per day) in analogy to girls with Ullrich-Turner syndrome and gonadal dysgenesis. With the exception of one patient in whom treatment was initiated only at the age of 14.6 years, the male patients with 45,X/46,XY mosaicism responded to short-term growth hormone treatment similarly to females with an increasing height SDS. Conclusion:45,X/46,XY mosaicism remains undetected in some short boys because this group is not routinely karyotyped. We recommend chromosomal analysis of boys with otherwise unexplained short stature who are short for their families. Growth hormone treatment should be offered to short boys with 45,X/46,XY mosaicism and a predicted adult height below the mid-parental range within clinical trials.Abbreviations FSH follicle stimulation hormone - GH growth hormone - IGF-I insulin-like growth factor 1 - IGFBP-3 insulin-like growth factor binding protein-3 - LH luteinising hormone - MPH mid-parental height     

WT1 mutation as a cause of 46 XY DSD and Wilm's tumour: a case report and literature review

Aim: The Wilms’ Tumour gene is thought to have tumour suppressor activity and to play an important role in nephrogenesis, genitourinary development, haematopoiesis and sex determination. WT1 mutations will impair gonadal and urinary tract development and have been demonstrated to cause syndromes of WAGR, Denys–Drash and Fraiser. Methods: To elucidate the role of constitutional mutations of WT1, in the expression of the different clinical feature, we describe a 14‐year‐9‐month nonmosaic XY sex‐reversed woman with pure gonadal dysgenesis (46, XY karyotype, completely female external genitalia, normal Mullerian ducts, absence of Wolffian ducts, streak gonads) who had right kidney removed at 7 months of age because of Wilms’ tumour and was diagnosed as secondary thrombocytopenia (Plt 60–80 × 10⁹/L) since she was 4 years old. We sequenced the genomic DNA of all the 10 exons of the WT1 in which mutations may occur in proposita. Results: A new de novo insertion mutation in the first exon was found. A ‘GCCGCCTCACTCC’ is inserted between codon 138 and 139, resulting in the creation of a stop codon and a truncated protein. Conclusion: The present data provide further evidence to support the role of WT1 in diverse cellular functions.     

Effects of the Y‐chromosome and the dominant hemimelia mutation on the morphology of the mouse mandible

The aims of this study were to test whether the Y‐chromosome and the autosomal dominant hemimelia (Dh) mutation can affect mandible morphology in mice. I analyzed mandible size and shape using landmark‐based geometric morphometrics in 16 DH‐Chr Y^@‐+/+ (@ represents one of the inbred strain names) strains and observed significant differences in mandible size. The largest mandible was identified in strain DH‐Chr Y^C3H and the smallest in strain DH‐Chr Y^KK. Canonical variate and discriminant function analyses suggested that the mandible shapes of strains DH‐Chr Y^C3H and DH‐Chr Y^KK differed from those of the other strains. Because seven of the DH‐Chr Y^@‐+/+ strains were maintained with dominant hemimelia, I also analyzed the potential influence of dominant hemimelia on mandible morphology because dominant hemimelia is known to cause various skeletal malformations. There were no significant differences in mandible size in seven sets of DH‐Chr Y^@‐+/+ and DH‐Chr Y^@‐Dh/+ strains. However, canonical variate analysis mapped strains DH‐Chr Y^CAS‐Dh/+ and DH‐Chr Y^CBA‐Dh/+ mapped distantly from the rest. Additionally, I observed similar patterns of shape change between DH‐Chr Y^CAS‐+/+ and DH‐Chr Y^CAS‐Dh/+, and between DH‐Chr Y^CBA‐+/+ and DH‐Chr Y^CBA‐Dh/+. These data indicate that the Y‐chromosome affects the size and shape of the mouse mandible. Dominant hemimelia affects mandible shape but not size, and its effects emerge depending on the kinds of Y‐chromosomes.     

Biology of the X chromosome.

The biology of the X chromosome is unique, as there are two Xs in females and only a single X in males, whereas the autosomes are present in duplicate in both sexes. The presence of only a single autosome, which can occur as a result of an error in meiotic segregation, is invariably an embryonic lethal event. Monosomy for the X chromosome is viable because of dosage compensation, a system found in all organisms with an X:Y form of sex determination, which brings about equality of expression of most X-linked genes in females and males. In mammals, the dosage compensation system involves silencing of most of the genes on one X chromosome; it is called X chromosome inactivation. In this review, we focus first on recent advances in our understanding of the molecular basis of the X inactivation mechanism. Then we consider an unusual feature of X inactivation, the mosaic nature of the female and subsequent exposure to somatic cell selection.     

Epigenetic abnormality of SRY gene in the adult XY female with pericentric inversion of the Y chromosome

In normal ontogenetic development, the expression of the sex‐determining region of the Y chromosome (SRY) gene, involved in the first step of male sex differentiation, is spatiotemporally regulated in an elaborate fashion. SRY is expressed in germ cells and Sertoli cells in adult testes. However, only few reports have focused on the expressions of SRY and the other sex‐determining genes in both the classical organ developing through these genes (gonad) and the peripheral tissue (skin) of adult XY females. In this study, we examined the gonadal tissue and fibroblasts of a 17‐year‐old woman suspected of having disorders of sexual differentiation by cytogenetic, histological, and molecular analyses. The patient was found to have the 46,X,inv(Y)(p11.2q11.2) karyotype and streak gonads with abnormally prolonged SRY expression. The sex‐determining gene expressions in the patient‐derived fibroblasts were significantly changed relative to those from a normal male. Further, the acetylated histone H3 levels in the SRY region were significantly high relative to those of the normal male. As SRY is epistatic in the sex‐determination pathway, the prolonged SRY expression possibly induced a destabilizing effect on the expressions of the downstream sex‐determining genes. Collectively, alterations in the sex‐determining gene expressions persisted in association with disorders of sexual differentiation not only in the streak gonads but also in the skin of the patient. The findings suggest that correct regulation of SRY expression is crucial for normal male sex differentiation, even if SRY is translated normally.     

Pediatric Renal Cell Carcinomas with Xp11.2 Rearrangements Are Immunoreactive for hMLH1 and hMSH2 Proteins

Alveolar soft part sarcoma and pediatric renal cell carcinoma share a similar chromosomal abnormality, t(X;17)(p11.2;q25). Recently, it has been suggested that the inactivation of DNA mismatch repair genes hMLH1 and hMSH2 may play an additional role in the pathogenesis of alveolar soft part sarcoma. Immunohistochemical expression of the proteins hMLH1 and hMSH2 is indicative of the activation status of the corresponding genes. We performed immunohistochemistry for hMLH1 and hMSH2 in 4 cases of pediatric renal cell carcinomas with Xp11.2 rearrangements. All cases showed nuclear immunoreactivity for both proteins, although the staining was patchy. Our study demonstrates that inactivation of the DNA mismatch repair genes hMLH1 and hMSH2 does not appear to play a role in the tumorigenesis of pediatric renal cell carcinomas with Xp11.2 rearrangements.     

Coexisting micronutrient deficiencies among Sri Lankan pre-school children: a community-based study

Assessing micronutrient status in children may also have the benefit of addressing the problems of various micronutrient deficiencies with a unified programmatic approach on a public health scale. A cross‐sectional survey in the Galle district of the micronutrient and anthropometric status of 248 children of ages 3–5 years was performed to determine the prevalence of micronutrient deficiencies [iron, zinc (Zn), folate, calcium, caeruloplasmin, iodine, vitamin A and vitamin D] and the extent to which multiple micronutrient deficiencies coexist. The prevalence of anaemia [haemogbolin (Hb) < 110.0 g L^?1] was 34.0% in males and 33.0% in females (overall 33.5%, gender difference, P = 0.92). In anaemic children, 7.0% of males and 15.0% of females were iron deficient (serum ferritin < 15.0 µg L^?1). Folate deficiency (<3.00 ng mL^?1) was found in 41.0% and 33.0% of male and female, respectively, whereas Zn deficiency (<9.95 µmol L^?1) occurred in 57.0% and 50.0% of male and female, respectively. Serum vitamin D deficiency (<35.0 nmol L^?1) was found in 26% and 25% of male and female, respectively. Anaemic males had a 3.0‐fold (95% confidence interval (CI) 1.1–8.3) and 2.3‐fold (95% CI 0.8–6.6) greater risk of being underweight and thin, whereas the risk among anaemic females was 0.7‐fold (95% CI 0.3–1.8) and 0.9‐fold (95% CI 0.3–2.6) for being underweight and thin. Only 7.3% of the subjects did not have any micronutrient deficiency, 38.3% were deficient in two micronutrients, 17.7% had three micronutrient deficiencies and 6.0% had four or more micronutrient deficiencies. Multiple micronutrient deficiencies are prevalent in Sri Lankan pre‐school children and established baseline data for future studies.     

Bilateral gonadoblastoma with dysgerminoma and pilocytic astrocytoma with WT1 GT‐IVS9 mutation: A 46 XY phenotypic female with Frasier syndrome

Frasier syndrome is characterized by a 46 XY disorder of sex development, nephropathy, and increased risk for gonadoblastoma due to Wilms tumor 1(WT1) mutation in the donor splice site of intron‐9, resulting in the splice form +KTS. Germ cell tumors and gonadoblastomas have been reported previously in Frasier syndrome. We present the clinical, radiological, and genetic (WT1 mutation analysis) of a 46 XY phenotypic female with Frasier syndrome with bilateral gonadoblastoma with dysgerminoma who developed pilocytic astrocytoma. Pediatr Blood Cancer 2009; 53:1349–1351. © 2009 Wiley‐Liss, Inc.     

Novel DCX mutation‐caused lissencephaly in a boy and very mild heterotopia in his mother

We describe a novel mutation in DCX in a family in which a proband boy had classical lissencephaly and his mother had extremely mild subcortical band heterotopia. No factors that would make the mother's symptoms milder, such as somatic mosaicism or skewed X chromosome inactivation, were observed. From this family, we conclude that a DCX mutation causes a pleiotropic phenotype in the female even if X chromosome inactivation pattern is not skewed, and the novel missense mutation in DCX produced relatively mild dysfunction of the doublecortin protein.     

Skewed X inactivation in healthy individuals and in different diseases

In female mammalian cells, one of the two X chromosomes is inactivated in early embryonic life. Females are mosaics for two cell populations, one with the maternal and one with the paternal X as the active chromosome. Skewed X inactivation is arbitrarily defined, often as a pattern where 80% or more of the cells show a preferential inactivation of one X chromosome. Inactivation is presumed to be permanent for all descendants of a cell; however, after about 55 years of age, the frequency of skewed X inactivation in peripheral blood cells increases, probably through selection. Unfavourable skewing of X inactivation, where the X chromosome carrying a mutant allele is the predominantly active X, has been found in affected female carriers of several X-linked disorders; however, for many X-linked disorders, a consistent relationship between the pattern of X inactivation and clinical phenotype has been difficult to demonstrate. One reason for this may be that peripheral blood cells are not a representative or relevant tissue in many disorders. In some severe X-linked disorders, post-inactivation selection takes place against the X chromosome carrying the mutant allele, leading to a completely skewed X-inactivation pattern. Skewed X inactivation has also been reported in young females with breast cancer, and may indicate an effect of X-linked genes on the development of this condition.
Conclusion: The process of X inactivation and the resultant degree of skewing is clearly important for the expression of genetic diseases. It is also important to consider, however, that under normal conditions the frequency of skewed X inactivation increases with age in peripheral blood cells. Analysis of the expression of a large proportion of the genes on the X chromosome has revealed that X-chromosome inactivation is more heterogeneous than previously thought.     

Skewed X inactivation in healthy individuals and in different diseases

In female mammalian cells, one of the two X chromosomes is inactivated in early embryonic life. Females are mosaics for two cell populations, one with the maternal and one with the paternal X as the active chromosome. Skewed X inactivation is arbitrarily defined, often as a pattern where 80% or more of the cells show a preferential inactivation of one X chromosome. Inactivation is presumed to be permanent for all descendants of a cell; however, after about 55 years of age, the frequency of skewed X inactivation in peripheral blood cells increases, probably through selection. Unfavourable skewing of X inactivation, where the X chromosome carrying a mutant allele is the predominantly active X, has been found in affected female carriers of several X-linked disorders; however, for many X-linked disorders, a consistent relationship between the pattern of X inactivation and clinical phenotype has been difficult to demonstrate. One reason for this may be that peripheral blood cells are not a representative or relevant tissue in many disorders. In some severe X-linked disorders, post-inactivation selection takes place against the X chromosome carrying the mutant allele, leading to a completely skewed X-inactivation pattern. Skewed X inactivation has also been reported in young females with breast cancer, and may indicate an effect of X-linked genes on the development of this condition.Conclusion: The process of X inactivation and the resultant degree of skewing is clearly important for the expression of genetic diseases. It is also important to consider, however, that under normal conditions the frequency of skewed X inactivation increases with age in peripheral blood cells. Analysis of the expression of a large proportion of the genes on the X chromosome has revealed that X-chromosome inactivation is more heterogeneous than previously thought.     

X-chromosome inactivation and human genetic disease

The inactivation of one X-chromosome in females in early development is the process by which the effective dosage of X-linked genes is equalized between XX females and XY males. The mechanism that brings this about is the subject of intense research. The X-linked gene Xist is a key player, which is necessary but not sufficient for the initiation of X-inactivation. It codes for an untranslated RNA that coats the inactive X-chromosome, which takes on properties characteristic of heterochromatin, but how this change in chromatin is brought about remains unknown. Because of X-inactivation, females heterozygous for X-linked genes are mixtures of two types of cells and show a variable phenotype. The proportion s of the two types of cells can depart from equality due to cell selection either at the tissue or whole organism level. In rare cases, changes in the Xist gene can cause skewing of X-inactivation. A few genes escape from X-inactivation either wholly or partially.
Conclusion : X-chromosome inactivation is a physiological mechanism that equalizes gene-dosage effects on the sex chromosomes. The occurrence of this normal process affects the phenotype seen in females carrying X-linked mutant genes or chromosome anomalies.     

X-chromosome inactivation and human genetic disease

The inactivation of one X-chromosome in females in early development is the process by which the effective dosage of X-linked genes is equalized between XX females and XY males. The mechanism that brings this about is the subject of intense research. The X-linked gene Xist is a key player, which is necessary but not sufficient for the initiation of X-inactivation. It codes for an untranslated RNA that coats the inactive X-chromosome, which takes on properties characteristic of heterochromatin, but how this change in chromatin is brought about remains unknown. Because of X-inactivation, females heterozygous for X-linked genes are mixtures of two types of cells and show a variable phenotype. The proportions of the two types of cells can depart from equality due to cell selection either at the tissue or whole organism level. In rare cases, changes in the Xist gene can cause skewing of X-inactivation. A few genes escape from X-inactivation either wholly or partially. CONCLUSION: X-chromosome inactivation is a physiological mechanism that equalizes gene-dosage effects on the sex chromosomes. The occurrence of this normal process affects the phenotype seen in females carrying X-linked mutant genes or chromosome anomalies.     

Molecular aspects of female and male gonadal development in mammals

In mammals, the choice between male or female development is genetically determined. Sex determination takes place when the embryonic gonad becomes either a testis or an ovary. This process is directed by genes that have been discovered by genetic analysis of sex-reversed patients and confirmed by knock-out experiments in mice. The testis-determining pathway is better known than the ovary pathway. SRY, a gene located on the Y chromosome, triggers a complex genetic cascade leading to testicular differentiation. In this cascade, two genes play a crucial role in male differentiation, SOX9 and FGF9, which contribute to testicular cord formation. However, only a minority of 46,XY sex-reversed patients can be explained by mutations in known genes such as SRY, SOX9, WT1 and SF1, suggesting that other genes influencing sex determination are yet to be discovered. In females, some rare genes that induce ovarian failure or female-to-male sex-reversal, have been found through gene-targeted inactivation in mice or positional cloning of mutations in humans and goats. In both sexes, genetic analysis of sex-reversed individuals (XX males, XX and XY hermaphrodites and XY with complete or partial dysgenesis) remains an approach of choice to isolate new genes involved in sex determination.     

Chronic granulomatous disease: Clinical,molecular, and therapeutic aspects

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency caused by defects in the genes encoding any of the NADPH oxidase components responsible for the respiratory burst of phagocytic leukocytes. CGD is a genetically heterogeneous disease with an X‐linked recessive (XR‐CGD) form caused by mutations in the CYBB gene encoding the gp91^phox protein, and an autosomal recessive (AR‐CGD) form caused by mutations in the CYBA, NCF1, NCF2, or NCF4 genes encoding p22^phox, p47^phox, p67^phox, and p40^phox, respectively. Patients suffering from this disease are susceptible to severe life‐threatening bacterial and fungal infections and excessive inflammation characterized by granuloma formation in any organ, for instance, the gastrointestinal and genitourinary tract. An early diagnosis of and the prompt treatment for these conditions are crucial for an optimal outcome of affected patients. To prevent infections, CGD patients should receive lifelong antibiotics and antifungal prophylaxis. These two measures, as well as newer more effective antimicrobials, have significantly modified the natural history of CGD, resulting in a remarkable change in overall survival, which is now around 90%, reaching well into adulthood. At present, hematopoietic stem cell transplantation (HSCT) is the only definitive treatment that can cure CGD and reverse organ dysfunction. Timing, donor selection, and conditioning regimens remain the key points of this therapy. In recent years, gene therapy (GT) for XR‐CGD has been proposed as an alternative to HSCT for CGD patients without a matched donor. After the failure of the first trials performed with retroviral vectors, some groups have proposed the use of regulated SIN‐lentiviral vectors targeting gp91^phox expression in myeloid cells to increase the safety and efficacy of the GT protocols.     

A family with Hoyeraal–Hreidarsson syndrome and four variants in two genes of the telomerase core complex

We describe an African American family with Hoyeraal–Hreidarrson syndrome (HHS) in which 2 TERT mutations (causing P530L and A880T amino acid changes) and two in the DKC1 variants (G486R and A487A) were segregating. Both genes are associated with dyskeratosis congenita and HHS. It was important to determine the importance of these mutations in disease pathogenesis to counsel family members. From genetic analysis of family members, telomere length and X‐inactivation studies we concluded that compound heterozygosity for the TERT mutations was the major cause of HHS and the DKC1 G486R variant is a rare African variant unlikely to cause disease. Pediatr Blood Cancer 2013; 60: E4–E6. © 2013 Wiley Periodicals, Inc.     

Alopecia congenita universalis,microcephaly, cutis marmorata,short stature and XY gonadal dysgenesis: variable expression of El-Shanti syndrome

Alopecia congenita, laryngomalacia, and XY gonadal dysgenesis has been reported recently as a new syndrome in two unrelated Arab families from Jordan. We report a 4-year-old girl of first cousin Arab parents who had alopecia, microcephaly, cutis marmorata, short stature and borderline cognitive development. Karyotype analysis revealed a male constitution (46,XY) with no deletion of STS or SRY. She showed entirely normal female external genitalia and absence of female internal genitalia. Histological examination of the very small testicles found on laparascopy showed developed spermatic cords and paratesticular tissue with no testicular parenchyma, no Sertoli or Leydig cell development, and no seminiferous tubular development. Hormonal profile was that of a normal female child. Southern blotting and PCR assays showed an intact Y chromosome. Limited sequencing of the SRY gene revealed no mutations. Conclusion: this patient, together with the recently reported consanguineous families, represent a previously unrecognised autosomal recessive trait with pleiotropic effects including XY gonadal dysgenesis.     

De novo phyllodes tumor in an adolescent female after liver transplantation

Cheng F, Qin J‐J, Yu M‐N, Zhang F, Li X‐C, Sun B‐C, Kong L‐B, Wang X‐H. De novo phyllodes tumor in an adolescent female after liver transplantation.
Pediatr Transplantation 2011: 15:E12–E14. © 2009 John Wiley & Sons A/S. Abstract: Phyllodes tumor of the breast is a rare disease constituting 0.3–0.9% of all breast neoplasms. Occurring mainly in females aged 35 to 55 yr, the disease is especially rare among adolescent females. There is no published literature about de novo phyllodes tumor after liver transplantation. Here we describe a case of de novo phyllodes tumors in an adolescent female after liver transplantation from a living donor for Wilson disease.     

Fatal hemophagocytic lymphohistiocytosis in X‐linked chronic granulomatous disease associated with a perforin gene variant

A patient with previously unrecognized X‐linked chronic granulomatous disease (X‐CGD) died of multi‐organ failure, secondary to ongoing infection and hemophagocytic lymphohistiocytosis (HLH). Post mortem histological investigations were compatible with X‐CGD, and a CYBB gene mutation was confirmed. No homozygous mutations in the genes encoding perforin (PRF1), MUNC 13‐4 or syntaxin‐11 (STX11) were found; however, there was a heterozygous alteration c.1471G>A in the PRF1 gene causing a p.Asp491Asn substitution. Although this substitution has not been reported to cause primary or secondary HLH, we speculate that it may have made the patient more susceptible for HLH under the circumstances of ongoing infection associated with X‐CGD. Pediatr Blood Cancer 2009;52:527–529. © 2008 Wiley‐Liss, Inc.     

Vincristine pharmacodynamics and pharmacogenetics in children with cancer: a limited-sampling, population modelling approach

Background: Vincristine is a key component of many childhood cancer treatment regimens. Pharmacodynamic parameters such as clinical efficacy and toxicity may be influenced by polymorphisms of CYP3A. Aim: The aim of this study was to document CYP3A5 genotype, vincristine pharmacokinetics (PK) and neurotoxicity profile for 50 children with cancer and determine whether, in a population of Australian children, the CYP3A5 genotype influenced the pharmacodynamics of vincristine as reflected by peripheral neurotoxicity. Methods: Blood for PK analysis was collected after any single dose of vincristine and assayed using high performance liquid chromatography with tandem mass spectrometry detection. CYP3A5*3 and CYP3A5*6 genotype was determined using gel‐electrophoresis or automated microfluidic electrophoresis. Neurotoxicity was determined by physical examination. Results: The median age of children sampled was 6.5 years (range 1–16.25). Half the patients received concurrent corticosteroids for acute lymphoblastic leukaemia. Six patients (12%) had experienced grade 3 or 4 neurotoxicity. The median clearance, area under the curve and Cmax of vincristine was 482 mL/min/m² (range 132–698), 49.7 mcg/L.h (16.5–143.1) and 3.5 mcg/L (1.0–31.2), respectively. In contrast to prediction, all but three children were homozygous for wild‐type CYP3A5*3. No CYP3A5*6 polymorphisms were identified. Conclusions: No correlation was identified between vincristine clearance, vincristine neurotoxicity, age, sex or concomitant steroid therapy. The limited sampling methodology proved acceptable to patients and families and would be suitable for larger scale studies including a wider range of genotypic variants and more detailed prospective evaluation of neurotoxicity.