Next generation sequencing (NGS) to improve the diagnosis and management of patients with disorders of sex development (DSD).

Disorders of sex development (DSDs) are a diverse group of conditions where the chromosomal, gonadal or anatomical sex can be atypical. The highly heterogeneous nature of this group of conditions often makes determining a genetic diagnosis challenging. Prior to next generation sequencing (NGS) technologies, genetic diagnostic tests were only available for a few of the many DSD-associated genes, which consequently had to be tested sequentially. Genetic testing is key in establishing the diagnosis, allowing for personalised management of these patients. Pinpointing the molecular cause of a patient's DSD can significantly impact patient management by informing future development needs, altering management strategies and identifying correct inheritance pattern when counselling family members. We have developed a 30-gene NGS panel, designed to be used as a frontline test for all suspected cases of DSD (both 46,XX and 46,XY cases). We have confirmed a diagnosis in 25 of the 80 patients tested to date. Confirmed diagnoses were linked to mutations in AMH, AMHR2, AR, HSD17B3, HSD3B2, MAMLD1, NR5A1, SRD5A2 and WT1 which have resulted in changes to patient management. The minimum diagnostic yield for patients with 46,XY DSD is 25/73. In 34/80 patients, only benign or likely benign variants were identified, and in 21/80 patients only variants of uncertain significance (VOUS) were identified, resulting in a diagnosis not being confirmed in these individuals. Our data support previous studies that an NGS panel approach is a clinically useful and cost-effective frontline test for patients with DSDs.

Delayed diagnosis in type 1 diabetes mellitus.

Children with suspected type 1 diabetes mellitus (T1DM) should have same day referral to a paediatric diabetes team. 99 children (54 male; median age 10.5 years, range 0.9-15.9 years) were diagnosed with T1DM at our hospital between January 2004 and June 2007. 27 (27.2%) presented in diabetic ketoacidosis (DKA). 37 (37.3%) required hospital admission, while the rest had ambulatory management. In 21 (21.2%) children, diagnosis was delayed >24 h (median 3.0 days, range 1-14 days) due to missed diagnosis at the local hospital (four) or by the general practitioner (seven), arranging a fasting blood glucose test (nine) and outpatient appointment requested via fax (one). Children with delayed diagnosis presented more frequently in DKA (52.3% vs 20.5%, p<0.01), with a higher median presenting HbA1c (12.3% vs 10.9%, p<0.05). There were no differences in age and sex between the delayed diagnosis and immediate referral groups. Healthcare providers need to be aware of the importance of immediate referral of children newly diagnosed with T1DM.

Body fat estimation using bioelectrical impedance.

BACKGROUND/AIMS: Although childhood obesity is a major problem, routine assessment methods do not reflect fat mass. Body mass index, which is most commonly used, gives an indication of weight for height and not a degree of adiposity. METHODS: Bioelectrical impedance and dual-energy X-ray absorptiometry (DEXA) were used in a group of obese children to assess body fat. RESULTS: Comparison between DEXA and commercial bioelectrical impedance scales in 46 children showed a highly significant correlation (R = 0.944, p < 0.001) in fat mass. Fat mass measured using bioelectrical impedance was 2.4 kg lower compared to measurement using DEXA. CONCLUSION: These bioelectrical scales may prove useful in the management of childhood obesity as they are able to provide important clinical information regarding fat mass and adiposity.

Factors determining patient choice of device for GH therapy.

AIM: To assess the factors determining patient choice of GH device, and whether offering free patient choice improves compliance with GH therapy. METHODS: A prospective cross-sectional study performed on patients offered free choice of GH device in a regional growth clinic. In a subgroup having home delivery, GH compliance was assessed using ampoule counts. RESULTS: 125 patients (74 (59%) male), median (range) 9.30 (1.0-18.3) years were commenced on GH from January 2001 to March 2004, and offered free choice of device. 68 (54%) chose a needled device, and 57 (46%) needle-free. There was no statistical difference in age, sex or diagnostic category between the two groups. Light blue devices were more likely to be chosen by males (p=0.056). Questionnaires giving reasons for choosing a device were available in 40, and a further 50 gave reasons for both choosing a specific device and not choosing others. Other than choice of needled/needle-free device, the factor most likely to determine choice was 'ease of use'. Only 6 (4.8%) subsequently changed device, and compliance remained high but unchanged at approximately 90%. CONCLUSIONS: There are no specific features which determine what GH device a patient will choose. For those units offering free patient choice, a wide range of different devices should be made available.

Mutation analysis of POUF-1, PROP-1 and HESX-1 show low frequency of mutations in children with sporadic forms of combined pituitary hormone deficiency and septo-optic dysplasia.

OBJECTIVES: Mutations in the genes encoding the transcription factors PROP1 and POUF-1 (Pit-1) have been reported as common causes of combined pituitary hormone deficiency (CPHD), and HESX1 mutations have been identified in children with septo-optic dysplasia (SOD). There are few data on UK children. We have performed mutation analysis in a large cohort of affected children within the West Midlands region to assess the feasibility of a screening strategy for molecular diagnosis in CPHD and SOD. DESIGN AND PATIENTS: The three coding exons of PROP1, and six exons of POUF-1 in 27 children from 26 families with CPHD, and three exons of HESX1 in 23 children from 22 families with SOD were directly sequenced from a well-characterized regional cohort. RESULTS: We identified a C to T transition in exon 6 of POUF-1, resulting in a known missense mutation (R271W) in a mother and daughter from one family with CPHD. We also found a novel homozygous T to C transition in exon 6 of POUF-1, resulting in a missense mutation (F233L) in a twin with CPHD. This mutation was excluded in 100 ethnically matched control alleles. We did not identify any mutations in the PROP1 gene or HESX1. The median maternal age at delivery for the CPHD children was 27 years, compared to 21 years for the mothers of SOD children (P = 0.04). CONCLUSIONS: Mutations in POUF-1, PROP1 and HESX1 are rare causes of CPHD and SOD, respectively, in children from the West Midlands. In particular, we did not confirm the reported 'hotspot' in PROP1. A screening strategy that targets familial cases is highly likely to increase the mutation yield. The young maternal age at conception of children with SOD and potential teratogen exposure indicate the predominance of environmental factors in this condition compared with CPHD.

Thyroxine unmasks Addison's disease.

UNLABELLED: Patients with primary hypothyroidism may also have other underlying associated endocrinopathies, which are important to exclude. A 15-y-old girl presented with clinical biochemical evidence of hypothyroidism. CONCLUSION: Thyroxine replacement unmasked Addison's disease and precipitated an acute adrenal crisis. On physiological steroid replacement therapy, her "hypothyroidism" resolved.

Progressive nodular histiocytosis in a child with a hypothalamic tumor.

We report a 13-year-old girl with multiple cutaneous histiocytic lesions, precocious puberty, growth hormone deficiency and a hypothalamic tumour. We conclude that she has progressive nodular histiocytosis, but this case illustrates the difficulty in differentiating the type II histiocytoses.