Conserved haplotype blocks within the sheep MHC and low SNP heterozygosity in the Class IIa subregion

This report describes single-nucleotide polymorphisms (SNPs) in the sheep major histocompatibility complex (MHC) class II and class III regions and provides insights into the internal structure of this important genomic complex. MHC haplotypes were deduced from sheep family trios based on genotypes from 20 novel SNPs representative of the class II region and 10 previously described SNPs spanning the class III region. All 30 SNPs exhibited Hardy-Weinberg proportions in the sheep population studied. Recombination within an extended sire haplotype was observed within the class II region for 4 of 20 sheep chromosomes, thereby supporting the presence of separated IIa and IIb subregions similar to those present in cattle. SNP heterozygosity varied across the class II and III regions. One segment of the class IIa subregion manifested very low heterozygosity for several SNPs spanning approximately 120 Kbp. This feature corresponds to a subregion within the human MHC class II region previously described as a 'SNP desert' because of its paucity of SNPs. Linkage disequilibrium (LD) was reduced at the junction separating the putative class IIb and IIa subregions and also between the class IIa and the class III subregions. The latter observation is consistent with either an unmapped physical separation at this location or more likely a boundary characterized by more frequent recombination between two conserved subregions, each manifesting high within-block LD. These results identify internal blocks of loci in the sheep MHC, within which recombination is relatively rare.

Molecular analysis of congenital adrenal hyperplasia due to 21-hydroxylase deficiency in Hong Kong Chinese patients

BACKGROUND

Congenital adrenal hyperplasia (CAH) caused by 21-hydroxylase deficiency (21OHD) is an autosomal recessive disorder due to mutation in the CYP21A2 gene.

OBJECTIVE

To elucidate the genetic basis of 21-hydroxylase-deficient CAH in Hong Kong Chinese patients.

PATIENTS AND METHODS

Mutational analysis of the CYP21A2 gene was performed on 35 Hong Kong Chinese patients with 21OHD using direct DNA sequencing and multiplex ligation-dependent probe amplification (MLPA).

RESULTS

The genetic findings of 21 male and 14 female patients are the following: c.293-13A/C>G (intron 2 splice site; 20 alleles), p.I172N (13), p.R356W (7), p.Q318X (4). A total of 20 mutant alleles contained gross deletion/conversion of all or part of the CYP21A2 gene. A novel mutation, c.1367delA (p.D456fs), was detected in one patient. One patient had only a heterozygous mutation detected. Out of 35 patients, 16 would have been incorrectly genotyped if either DNA sequencing or MLPA alone was used for molecular analysis.

CONCLUSIONS

The frequency of various mutations in the studied patients differs from those reported in other Asian populations. Gross deletion/conversion accounts for nearly one-third of the genetic defects. Therefore, laboratories must include methods for detecting point mutations as well as gross deletions/conversions to avoid misinterpretation of genotype. Genotyping has increasingly been proven to be a useful tool for supplementing, if not replacing, hormonal profiling for the diagnosis of 21OHD.

A synopsis of current care of thalassaemia major patients in Hong Kong

OBJECTIVE

To provide a synopsis of current thalassaemia major patient care in Hong Kong.

DESIGN

Retrospective study.

SETTING

All haematology units of the Hospital Authority in Hong Kong.

PATIENTS

All patients with thalassaemia major with regular transfusion.

RESULTS

To date, there were 363 thalassaemia major patients under the care of the Hospital Authority. Prenatal diagnosis has helped to reduce the number of indigenous new cases, but in recent years immigrant cases are appearing. The patients have a mean age of 23 (range, 1-52) years, and 78% of them are adults. In 2009, they received 18 782 units of blood. This accounted for 9.5% of all blood consumption from the Hong Kong Red Cross. In the past, cardiac iron overload was the major cause of death (65%) and few patients survived beyond the age of 45 years. The availability of cardiac iron assessment by magnetic resonance imaging (T2 MRI) to direct the use of oral deferiprone chelation has reduced the prevalence of heart failure and cardiac haemosiderosis, which should reduce mortality and improve life expectancy.

CONCLUSION

The future for thalassaemia care in Hong Kong is bright. With better transfusion and chelation, it should be possible to avoid growth and endocrine deficiencies in younger patients.

Successful endosaccular coiling after a balloon occlusion test of the caudal channel of a double origin of the posterior inferior cerebellar artery originating from the aneurysm neck

Therapeutic strategies for unruptured aneurysms in elective procedures must be carefully planned with respect to safety. We describe the case of a patient who presented with an unruptured aneurysm associated with a double origin of the posterior inferior cerebellar artery (DOPICA), a rare variant of aberrant origin. A three-dimensional rotational angiogram clearly showed that the aneurysm incorporated the origin of the DOPICA caudal channel, which was more dominant than the cranial one. The aneurysm was completely obliterated using detachable coils after a balloon occlusion test (BOT) of the caudal channel was conducted to confirm the tolerance of the patient following sudden interruption of the more prominent flow coming from the caudal channel of the DOPICA. This report affirms the need to suspect anomalies associated with a DOPICA that predispose to intracranial aneurysms and highlights the potential role of a BOT in pretreatment hemodynamic evaluations of unusual aneurysms accompanying a particular developmental anomaly.

A synopsis of current haemophilia care in Hong Kong

OBJECTIVE

To provide a synopsis of current haemophilia care in Hong Kong.

DESIGN

Retrospective survey.

SETTING

All haematology units of the Hospital Authority in Hong Kong.

PATIENTS

All patients with haemophilia A and haemophilia B.

RESULTS

To date, there were 222 mild-to-severe haemophilia patients (192 type A, 30 type B) under regular public care in Hong Kong (43% were considered severe, 33% moderate, and 24% mild), which gave a crude prevalence of 6.8/100 000 male inhabitants. A total of 12.8 million units of Factor VIII and 3 million units of Factor IX were prescribed annually. This amounts to 1.83 units of FVIII per capita of the population, which is comparable to that of other developed countries. Leading causes of mortality were human immunodeficiency virus-related complications (10 cases) and cerebral bleeding (2 cases). The life expectancy of patients with severe haemophilia in Hong Kong is improving; currently the oldest patient is 60 years old. Such improved survival may be due to enhanced factor availability, prompt treatment of bleeding episodes at home, safer factor products, and better antiviral treatment. Primary prophylaxis is the accepted standard of care for severe and moderate cases, and "Factor First" has become hospital policy. However, 12 patients continue to present treatment challenges, due to the documented presence of factor inhibitors. In all, 28, 100, and 14 cases respectively were positive for human immunodeficiency virus, hepatitis C virus, and hepatitis B virus; the youngest patients with the corresponding infections being 28, 13, and 22 years old. Comprehensive care with dedicated physiotherapy, surgical support, and radionucleotide synovectomy may reduce morbidity further.

CONCLUSION

A multidisciplinary approach can further improve the future care for haemophilia patients in Hong Kong.

Development and validation of molecular markers for characterization of Boehmeria nivea var. nivea and Boehmeria nivea var. tenacissima

BACKGROUND

The root of Boehmeria spp (ramie) is a hepatoprotective Chinese herbal medicine. Medicinal properties vary between Boehmeria nivea var. nivea and Boehmeria nivea var. tenacissima, which are local species found in Taiwan. As commercial preparations may use either species, there is a need for a rapid and simple assay to identify variants for quality control.

METHODS

Four methods were developed and tested for their applicability in differentiating the two species. These methods were random amplified polymorphic DNA (RAPD); sequence characterized amplified regions (SCAR); single nucleotide polymorphisms (SNP) and cleaved amplified polymorphic sequences (CAPS).

RESULTS

Three RAPD markers were developed that produced unique bands in B. nivea var. tenacissima and B. nivea var. nivea. Based on sequenced RAPD bands, one SCAR marker was developed that produced a single DNA band in B. nivea var. nivea. Two SNP markers differentiated between B. nivea var. nivea and B. nivea var. tenacissima based on single nucleotide substitutions. A pair of CAPS oligonucleotides was developed by amplifying a 0.55-kb DNA fragment that exhibited species-specific digestion patterns with restriction enzymes Alf III and Nde I. Consistent results were obtained with all the four markers on all tested Boehmeria lines.

CONCLUSION

The present study demonstrates the use of the RAPD, SCAR, SNP and CAPS markers for rapid identification of two closely related Boehmeria species.

Keeping neural progenitor cells on a short leash during Drosophila neurogenesis

The developmental potential of stem cells and progenitor cells must be functionally distinguished to ensure the generation of diverse cell types while maintaining the stem cell pool throughout the lifetime of an organism. In contrast to stem cells, progenitor cells possess restricted developmental potential, allowing them to give rise to only a limited number of post-mitotic progeny. Failure to establish or maintain restricted progenitor cell potential can perturb tissue development and homeostasis, and probably contributes to tumor initiation. Recent studies using the developing fruit fly Drosophila larval brain have provided molecular insight into how the developmental potential is restricted in neural progenitor cells.

Sedimentary 12-n-Propylcholestanes, Molecular Fossils Diagnostic of Marine Algae

Certain C(30)-steranes have been used for identifying sedimentary rocks and crude oils derived from organic matter deposited in marine environments. Analysis of a C(30)-sterane from Prudhoe Bay oil indicates that these C(30)-steranes are 24-n-propylcholestanes that apparently are derived from precursor sterols 24-n-propylidene-cholesterols and 24-n-propylcholesterol. These widely occurring sterols are biochemically synthesized in modern oceans by members of an order (Sarcinochrysidales) of chrysophyte algae. These data thus imply that C(30)-sterane biomarkers in sedimentary rocks and crude oils have a marine origin. Screening of a few organic-rich sedimentary rocks and oils from throughout the Phanerozoic suggests that these C(30)-steranes first appeared and, therefore, their source algae evolved between Early Ordovician and Devonian.

Multicolor fluorescence RNA in situ hybridization of Drosophila brain tissue

RNA in situ hybridization is a useful method for determining the transcriptional expression pattern of a gene when antibodies are not available. Using this technique, it is possible to assay the expression of multiple RNA species using distinct labels on RNA probes, or simultaneously examine RNA and protein localization within larval tissues. This protocol describes RNA in situ hybridization of Drosophila brain tissue. It utilizes a fluorophore-conjugated tyramide that is easily made in the laboratory for a fraction of the cost of the commercially produced product.

EdU (5-ethynyl-2'-deoxyuridine) labeling of Drosophila mitotic neuroblasts

When examining mutants that affect cell fate as a result of altered asymmetric division patterns, it is important to determine whether cells are mitotically active. Chemical labeling of newly synthesized DNA (during S-phase) by incorporation of BrdU (5-bromo-2'-deoxyuridine) is informative because this thymidine analog can be used to pulse-label dividing cells and then chased to identify the progeny of dividing cells. Such pulse-chase experiments can provide additional insight by distinguishing actively dividing cells from those that might be arrested at a mitotic checkpoint. EdU (5-ethynyl-2'-deoxyuridine) is another thymidine analog that provides a more sensitive and practical alternative to BrdU. Incorporation of EdU is detected through its reaction with an azide dye that is small enough to penetrate tissues efficiently. Visualization of EdU is rapid and does not interfere with subsequent antibody staining. The use of EdU in labeling Drosophila mitotic neuroblasts is described here.

Immunofluorescent staining of Drosophila larval brain tissue

INTRODUCTION

The Drosophila larval brain is a well-established model for investigating the role of stem cells in development. Neuroblasts (neural stem cells) must be competent to generate many thousands of differentiated neurons through asymmetric divisions during normal development. Studies in fly neuroblasts have been instrumental in identifying how the establishment and maintenance of cell polarity influence cell fate, and they have produced a wide array of molecular cell-polarity markers. Moreover, neuroblasts and their progeny can be positively identified using a variety of cell-fate markers. This article describes procedures for the collection and processing of Drosophila larval brains for examination by immunolocalization of cell-fate and cell-polarity markers. The protocol can be used for dissecting, fixing, and staining brains from larvae at any developmental stage. The number of brains processed using this method is limited only by how many brains can be dissected in 20 min, which is the maximum amount of time dissected tissues should remain in buffer before fixation. This protocol can be used for simultaneous costaining of multiple proteins.

Short-term influence of phosphate and nitrate on heavy metal accumulation by red alga Acrosorium uncinatum

Heavy metal accumulation (Cu, Zn, Ni, and Pb) in common marine macroalga, Acrosorium uncinatum under nutrient (phosphate and nitrate) enriched (experiment 1) and starved (experiment 2) conditions over a short exposure period (12 h) were examined in this study. Control was maintained in seawater contained nutrient solution without addition of metals and in seawater alone for experiment 1 and 2, respectively. Among the four metals studied, the accumulation of Zn, Ni, and Pb was considerably lower than Cu. The accumulation factor for all metals varies greatly in different nutrient concentrations, but it increases as the exposure of metal concentration decreases in both the experiments. The results of the present findings established that this macroalga is an accumulator of metals Cu, Zn, Ni, and Pb and have the potential to accumulate these metals even in a short time exposure period (12 h). Even though metal accumulation by A. uncinatum largely depends on the available concentration in the medium, nutrients like phosphate and nitrate can affect the accumulation significantly.

Practical considerations in converting from plasma-derived to recombinant hepatitis B vaccines

Plasma-derived and recombinant vaccines have been developed to prevent hepatitis B virus infections. Both types of vaccine perform very well with respect to safety, immunogenicity and protective efficacy. The protection afforded by both types of vaccine is satisfactory for at least 5 to 10 years after vaccination, and a further booster dose is not necessary during this period. However, the plasma-derived vaccine is costly to produce and there is an unjustified but prevalent fear that it may be contaminated by potential pathogens. The supply of human plasma for production of the plasma-derived vaccine cannot be assured once use of hepatitis B vaccines becomes universal. It is therefore inevitable that the recombinant vaccine will replace the plasma-derived vaccine. If necessary, both vaccines can be used in combination. Future directions for hepatitis B vaccine development include: determination of the need for incorporation of pre-S gene products to enhance immunogenicity; defining a practical strategy to combat the problem of escape mutants after vaccination; and development of combination vaccines containing other inactivated antigens to allow complete immunisation against several diseases with a minimal number of injections.

Polymorphism of sheep MHC Class IIb gene TAPASIN

The Major Histocompatibility Complex (MHC) is one of the most gene dense regions in the genome and studies in several species have shown significant associations between the MHC and disease. The endoplasmic reticular glycoprotein, tapasin, is involved in the MHC class I antigen presentation pathway. Sheep TAPASIN is located in the class IIb region of the MHC. Sheep TAPASIN was subcloned from BAC and cosmid genomic clones and DNA sequenced. TAPASIN is 9549bp in length and encodes a protein of 447 amino acids. The structure of sheep TAPASIN was similar to other mammals and consisted of eight exons with a distinctively larger intron between exon three and four. Sheep TAPASIN gene had high sequence identity with other mammalian TAPASINs. The TAPASIN gene sequence is conserved across many mammalian species and is possibly maintained through purifying selection with the average ratio of ds/dn of 3.9. Twenty-six SNPs in sheep TAPASIN were identified.

Interspecific competition between the Smooth cockroach Symploce pallens and the German cockroach Blattella germanica (Dictyoptera: Blattellidae) under different food and water regimes

The interspecific competition between a new cockroach pest species in Southeast Asia, the Smooth cockroach, Symploce pallens (Stephens) and the ubiquitous German cockroach, Blattella germanica (L.) was studied under different food and water regimes (unlimited food and water [control], limited water, limited food and limited food and water). Both species were found to have equal chances to coexist when both food and water are unlimited, when food is a limiting factor, and when both food and water are limited. However, under shorter evaluation periods (eg. 60 and 120 days), the intrinsic rate of increase (rn) of S. pallens appeared to be significantly lower than that of the B. germanica. This is possibly due to the shorter nymphal development period and higher fecundity of the latter species when compared to S. pallens. Both the food and water availability factor showed significant effects on the rn of both species.

dFezf/Earmuff maintains the restricted developmental potential of intermediate neural progenitors in Drosophila

To ensure normal development and maintenance of homeostasis, the extensive developmental potential of stem cells must be functionally distinguished from the limited developmental potential of transit amplifying cells. Yet the mechanisms that restrict the developmental potential of transit amplifying cells are poorly understood. Here we show that the evolutionarily conserved transcription factor dFezf/Earmuff (Erm) functions cell-autonomously to maintain the restricted developmental potential of the intermediate neural progenitors generated by type II neuroblasts in Drosophila larval brains. Although erm mutant intermediate neural progenitors are correctly specified and show normal apical-basal cortical polarity, they can dedifferentiate back into a neuroblast state, functionally indistinguishable from normal type II neuroblasts. Erm restricts the potential of intermediate neural progenitors by activating Prospero to limit proliferation and by antagonizing Notch signaling to prevent dedifferentiation. We conclude that Erm dependence functionally distinguishes intermediate neural progenitors from neuroblasts in the Drosophila larval brain, balancing neurogenesis with stem cell maintenance.

Ministry of Health clinical practice guidelines: Management of Rhinosinusitis and Allergic Rhinitis

The Ministry of Health publishes national clinical practice guidelines to provide doctors and patients in Singapore with evidence-based guidance on managing important medical conditions. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the Ministry of Health clinical practice guidelines on Management of Rhinosinusitis and Allergic Rhinitis, for the information of readers of the Singapore Medical Journal. Chapters, page and figure numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website (http://www.moh.gov.sg/mohcorp/publications.aspx?id=24046). The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Percutaneous transcatheter aortic valve replacement: first transapical implant in Asia

Percutaneous transcatheter implantation of the aortic valve has been demonstrated as an alternative to open heart surgery in high-risk patients with symptomatic severe aortic stenosis (AS) who are not suitable for open surgery. The majority of these new devices are delivered via the transfemoral approach. However, due to the current size of delivery sheaths, the small and tortuous iliofemoral anatomy makes this approach challenging. The transapical approach provides a viable option for this patient subgroup. The first-in-Asia transcatheter aortic valve implantation via the transapical route is described. A 79-year-old Chinese woman with symptomatic severe AS and peripheral arterial disease, who was at high surgical risk, was successfully treated, and had good functional and haemodynamic results at the three-month follow-up.

Use of urinary steroid profiling for diagnosing and monitoring adrenocortical tumours

It has been suggested that urinary steroid profiling may be used to provide information aiding the diagnosis and monitoring of adrenocortical carcinoma. Nonetheless, the abnormal patterns suggestive of adrenal malignancy are not well defined. We retrospectively studied the urinary steroid profiles of five patients with adrenocortical carcinoma at presentation and at follow-up, and compared these results with those from 76 patients with benign adrenocortical adenoma and 172 healthy controls. Three abnormal patterns of urinary steroid excretion were identified in patients with adrenocortical carcinoma at presentation and/or follow-up of residual disease: (1) hypersecretion in multiple steroid axes; (2) excretion of unusual metabolites, notably 5-pregnene-3alpha,16alpha,20alpha-triol, 5-pregnene-3beta,16alpha,20alpha-triol, and neonatal steroid metabolites in the post-neonatal period; (3) increase of tetrahydro-11-deoxycortisol relative to total cortisol metabolites. These preliminary findings offer ways in which urinary steroid profiling performed using gas chromatography-mass spectrometry can be helpful in the diagnosis and monitoring of adrenocortical carcinoma.

White-light electroluminescence from ZnO nanorods/polyfluorene by solution-based growth

We report bright white-light electroluminescence (EL) from a diode structure consisting of a ZnO nanorod (NR) and a p-type conducting polymer of poly(fluorine) (PF) fabricated using a hydrothermal method. ZnO NRs are successfully grown on an organic layer of PF using a modified seeding layer. The EL spectrum shows a broad emission band covering the entire visible range from 400 to 800 nm. White-light emission is possible because the ZnO-defect-related emission from the ZnO NR/PF heterostructure is enhanced to become over thousand times stronger than that from the usual ZnO NR structure. This strong green-yellow emission associated with the ZnO defects, combined with the blue PF-related emission, results in the white-light emission. Enhancement of the ZnO-defect emission is caused by the presence of Zn(OH)(2) at the interface between the ZnO NRs and PF. Fourier transform infrared spectroscopy reveals that the absorption peaks at 3441, 3502, and 3574 cm(-1) corresponding to the OH group are formed at the ZnO NR/PF heterostructure, which confirms the enhancement of defect emission from the ZnO NR/PF heterostructure. The processing procedure revealed in this work is a convenient and low-cost way to fabricate ZnO-based white-light-emitting devices.

Survey of commercially available chocolate- and cocoa-containing products in the United States. 2. Comparison of flavan-3-ol content with nonfat cocoa solids, total polyphenols, and percent cacao

A survey of a broad range of chocolate- and cocoa-containing products marketed in the United States was conducted to provide a more detailed analysis of flavan-3-ol monomers, oligomers, and polymers, which can be grouped into a class of compounds called procyanidins. Samples consisted of the three or four top-selling products within the following six categories: natural cocoa powder, unsweetened baking chocolate, dark chocolate, semisweet baking chips, milk chocolate, and chocolate syrup. Composite samples were characterized for percent fat (% fat), percent nonfat cocoa solids (% NFCS), antioxidant level by ORAC, total polyphenols, epicatechin, catechin, total monomers, and flavan-3-ol oligomers and polymers (procyanidins). On a gram weight basis epicatechin and catechin content of the products follow in decreasing order: cocoa powder > baking chocolate > dark chocolate = baking chips > milk chocolate > chocolate syrup. Analysis of the monomer and oligomer profiles within product categories shows there are two types of profiles: (1) products that have high monomers with decreasing levels of oligomers and (2) products in which the level of dimers is equal to or greater than the monomers. Results show a strong correlation (R(2) = 0.834) of epicatechin to the level of % NFCS and also very good correlations for N = 2-5 oligomers to % NFCS. A weaker correlation was observed for catechin to % NFCS (R(2) = 0.680). Other analyses show a similar high degree of correlation with epicatechin and N = 2-5 oligomers to total polyphenols, with catechin being less well correlated to total polyphenols. A lesser but still good correlation exists between the calculated percent cacao (calcd % cacao) content, a proxy for percent cacao, and these same flavanol measures, with catechin again showing a lesser degree of correlation to calcd % cacao. Principal component analysis (PCA) shows that the products group discretely into five classes: (1) cocoa powder, (2) baking chocolate, (3) dark chocolate and semisweet chips, (4) milk chocolates, and (5) syrup. PCA also shows that most factors group closely together including the antioxidant activity, total polyphenols, and the flavan-3-ol measures with the exception of catechin and % fat in the product, which group separately. Because catechin distribution appears to be different from the other flavan-3-ol measures, an analysis of the epicatechin to catechin ratio was done, indicating there is a >5-fold variation in this measure across the products studied. The cocoa-containing products tested range from cocoa powder with 227.34 +/- 17.23 mg of procyanidins per serving to 25.75 +/- 9.91 mg of procyanidins per serving for chocolate syrup. These results are discussed with respect to other studies on commercial products, the bioavailability of the flavanols, and the possible role of processing on the amount of catechin in products.

Percutaneous transcatheter aortic valve replacement: first transfemoral implant in Asia

Surgical aortic valve replacement (AVR) is the standard of care for patients with symptomatic severe aortic stenosis (AS), providing relief of symptoms and prolonging survival. However, many patients are either denied or not offered surgery due to high surgical risk or non-operability for open AVR. The technology of percutaneous aortic valve implantation emerged in 2002, and has since evolved rapidly with satisfactory results. Currently, almost all the procedures are performed predominantly in Europe and North America. The first-in-Asia percutaneous transcatheter aortic valve implantation via the transfemoral route is described. A 77-year-old man with symptomatic severe AS and at high surgical risk was successfully treated, with sustained clinical improvement and satisfactory haemodynamic results at 30-day follow-up.

Diagnosis of 5alpha-reductase 2 deficiency: a local experience

5Alpha-reductase 2 deficiency is an autosomal recessive disorder characterised by lack of masculinisation in XY individuals due to failure to convert testosterone to dihydrotestosterone, the bioactive androgen. Traditionally, the testosterone-to-dihydrotestosterone ratio is used to diagnose this condition but interpreting these results is not always straightforward, thus they may be inconclusive. On the contrary, urinary steroid profiling unambiguously demonstrates a significantly reduced excretion of 5alpha-reduced steroid metabolites compared to their 5beta counterparts. This analytical technique can also simultaneously confirm or rule out other causes of ambiguous genitalia due to steroidogenic defects. Making a DNA-based diagnosis by studying the SRD5A2 gene has become increasingly popular. Here, we report six Chinese patients from different families who were all diagnosed with 5alpha-reductase 2 deficiency based on urinary steroid profile findings and mutational analysis of the SRD5A2 gene. R227Q was the most commonly identified mutation in these patients. Management of sexual development disorders is also discussed.