Risk Assessment for Huntington's Disease for (Future) Offspring Requires Offering Preconceptional CAG Analysis to Both Partners

Amongst the main reasons people at risk for Huntington's disease (HD) have for undergoing predictive genetic testing are planning a family and prevention of passing on an expanded CAG-repeat to future offspring. After having received an unfavourable test result, a couple may consider prenatal testing in the foetus or preimplantation genetic diagnostic testing (PGD) in embryos. Testing of the foetus or embryos is possible by means of direct testing of the expanded repeat. Optimal reliability in testing the foetus or embryos requires the establishment of the origin of the repeats of both parents in the foetus. For PGD the analysis is combined with or sometimes solely based on identification of the at-risk haplotype in the embryo. This policy implies that in the context of direct testing, the healthy partner's CAG repeat lengths in the HD gene are also tested, but with the expectation that the repeat lengths of the partner are within the normal range, with the proviso that the partner's pedigree is free of clinically confirmed HD. However, recent studies have shown that the expanded repeat has been observed more often in the general population than previously estimated. Moreover, we have unexpectedly observed an expanded repeat in the non-HD partner in four cases which had far-reaching consequences. Hence, we propose that in the context of reproductive genetic counselling, prior to a planned pregnancy, and irrespective of the outcome of the predictive test in the HD-partner, the non-HD partner should also be given the option of being tested on the expanded allele. International recommendations for predictive testing for HD should be adjusted.Genetics of disease, diagnosis and treatmen

Reply to Oliver W Quarrell et al.:"Letter in response to Tibben et al., Risk Assessment for Huntington's Disease for (Future) Offspring Requires Offering Preconceptional CAG Analysis to Both Partners"

Genetics of disease, diagnosis and treatmen

Differential diagnosis of the short IGF-I-Deficient child with apparently normal growth hormone secretion

The current differential diagnosis for a short child with low insulin-like growth factor I (IGF-I) and a normal growth hormone (GH) peak in a GH stimulation test (GHST), after exclusion of acquired causes, includes the following disorders: (1) a decreased spontaneous GH secretion in contrast to a normal stimulated GH peak ("GH neurosecretory dysfunction," GHND) and (2) genetic conditions with a normal GH sensitivity (e.g., pathogenic variants of GH1 or GHSR) and (3) GH insensitivity (GHI). We present a critical appraisal of the concept of GHND and the role of 12- or 24-h GH profiles in the selection of children for GH treatment. The mean 24-h GH concentration in healthy children overlaps with that in those with GH deficiency, indicating that the previously proposed cutoff limit (3.0-3.2 mu g/L) is too high. The main advantage of performing a GH profile is that it prevents about 20% of false-positive test results of the GHST, while it also detects a low spontaneous GH secretion in children who would be considered GH sufficient based on a stimulation test. However, due to a considerable burden for patients and the health budget, GH profiles are only used in few centres. Regarding genetic causes, there is good evidence of the existence of Kowarski syndrome (due to GH1 variants) but less on the role of GHSR variants. Several genetic causes of (partial) GHI are known (GHR, STAT5B, STAT3, IGF1, IGFALS defects, and Noonan and 3M syndromes), some responding positively to GH therapy. In the final section, we speculate on hypothetical causes.Developmen

The IGSF1 deficiency syndrome may present with normal free T4 levels, severe obesity, or premature testicular growth

Our objective was to further expand the spectrum of clinical characteristics of the IGSF1 deficiency syndrome in affected males. These characteristic include almost universal congenital central hypothyroidism (CeH) with disharmonious pubertal development (normally timed testicular growth, but delayed rise of serum testosterone), macroorchidism, increased body mass index (BMI), and decreased attentional control. In addition, a subset of patients show prolactin deficiency, transient partial growth hormone deficiency in childhood and increased growth hormone secretion in adulthood. We present a family in which the proband was diagnosed with CeH and low serum prolactin. Severe weight gain started at two years old, with a BMI of 42.3 at 13.9 years. Testicular enlargement (5-6 mL, 3.8-4.3 standard deviation score) started aged three years. A pathogenic variant was found in the IGSF1 gene: c.3411_3412del, p.(Tyr1137*). His brother was referred for short stature at age 13 years and was diagnosed with CeH, normal serum prolactin and IGF-1, and disharmonious puberty. In four male relatives (the proband's brother and three cousins) with the variant (one adult), free thyroxine (fT4) was below the lower limit of the reference range in two, and just above this limit in the other two. Three were overweight or obese, adolescents had disharmonious pubertal development and the adult had profound macroorchidism. In conclusion, male hemizygous carriers of a pathogenic IGSF1 variant can present with fT4 concentration above the lower limit of the reference range while severe early onset obesity or premature testicular growth are part of the phenotypic spectrum.Genetics of disease, diagnosis and treatmen

Novel Clinical Criteria Allow Detection of Short Stature Homeobox-Containing Gene Haploinsufficiency Caused by Either Gene or Enhancer Region Defects

Introduction: Short stature homeobox-containing gene (SHOX) haploinsufficiency is associated with short stature, Madelung deformity and mesomelia. Current clinical screening tools are based on patients with intragenic variants or deletions. However, recent discoveries showed that deletions of the enhancer elements are quite common. The majority of these patients show less body disproportion and respond better to recombinant human growth hormone treatment. We redefined clinical criteria for genetic analysis to facilitate detection of the full spectrum of SHOX haploinsufficiency. Methods: We analyzed 51 children with SHOX variants or deletions and 25 children with a deletion in its enhancer region. Data were compared to 277 children referred for suspicion of growth failure without endocrine or genetic pathology. Results: Only half of the patients with an enhancer region deletion fulfilled any of the current screening criteria. We propose new clinical criteria based on sitting height to height ratio >1 SDS or arm span ≥3 cm below height, with a sensitivity of 99%. When these criteria are combined with obligatory short stature, the sensitivity to detect SHOX haploinsufficiency is 68.1%, the specificity 80.6%, and the number needed to screen 21 patients. Conclusion: Novel clinical criteria for screening for SHOX haploinsufficiency allow the detection of patients within the full genetic spectrum, that is, intragenic variants and enhancer region deletions

Novel Leptin Receptor Mutations Identified in Two Girls with Severe Obesity Are Associated with Increased Bone Mineral Density

Background: Recessive mutations in the leptin receptor (LEPR) are a rare cause of hyperphagia and severe early-onset obesity. To date, the phenotype has only been described in 25 obese children, some of whom also had altered immune function, hypogonadotropic hypogonadism, reduced growth hormone secretion, hypothalamic hypothyroidism or reduced adult height. We provide a detailed description of the phenotype of 2 affected girls to add to this knowledge. Methods: Whole-exome sequencing and targeted sequencing were used to detect the LEPR mutations. RNA analysis was performed to assess the effect of splice-site mutations. Results: In 2 unrelated girls with severe obesity, three novel LEPR mutations were detected. Longitudinal growth data show normal childhood growth, and in the older girl, a normal adult height despite hypogonadotropic hypogonadism and the lack of an obvious pubertal growth spurt. Bone age is remarkably advanced in the younger (prepubertal) girl, and bone mineral density (BMD) is high in both girls, which might be directly or indirectly related to leptin resistance. Conclusion: The spectrum of clinical features of LEPR deficiency may be expanded with increased BMD. Future observations in LEPR-deficient subjects should help further unravel the role of leptin in human bone biology

Phenotypic characterization of patients with deletions in the 3’-flanking SHOX region

Context. Leri–Weill dyschondrosteosis is a clinically variable skeletal dysplasia, caused by SHOX deletion or mutations, or a deletion of enhancer sequences in the 3’-flanking region. Recently, a 47.5 kb recurrent PAR1 deletion downstream of SHOX was reported, but its frequency and clinical importance are still unknown.Objective. This study aims to compare the clinical features of different sizes of deletions in the 3’-flanking SHOX region in order to determine the relevance of the regulatory sequences in this region.Design. We collected DNA from 28 families with deletions in the 3’-PAR1 region. Clinical data were available from 23 index patients and 21 relatives.Results. In 9 families (20 individuals) a large deletion ( ∼ 200–900 kb) was found and in 19 families (35 individuals) a small deletion was demonstrated, equal to the recently described 47.5 kb PAR1 deletion. Median height SDS, sitting height/height ratio SDS and the presence of Madelung deformity in patients with the 47.5 kb deletion were not significantly different from patients with larger deletions. The index patients had a median height SDS which was slightly lower than in their affected family members (p = 0.08). No significant differences were observed between male and female patients.Conclusions. The phenotype of patients with deletions in the 3’-PAR1 region is remarkably variable. Height, sitting height/height ratio and the presence of Madelung deformity were not significantly different between patients with the 47.5 kb recurrent PAR1 deletion and those with larger deletions, suggesting that this enhancer plays an important role in SHOX expression

State of the California current 2012-13: No such thing as an “average” year

This report reviews the state of the California Current System (CCS) between winter 2012 and spring 2013, and includes observations from Washington State to Baja California. During 2012, large-scale climate modes indicated the CCS remained in a cool, productive phase present since 2007. The upwelling season was delayed north of 42°N, but regions to the south, especially 33° to 36°N, experienced average to above average upwelling that persisted throughout the summer. Contrary to the indication of high production suggested by the climate indices, chlorophyll observed from surveys and remote sensing was below average along much of the coast. As well, some members of the forage assemblages along the coast experienced low abundances in 2012 surveys. Specifically, the concentrations of all lifestages observed directly or from egg densities of Pacific sardine, Sardinops sagax, and northern anchovy, Engraulis mordax, were less than previous years’ survey estimates. However, 2013 surveys and observations indicate an increase in abundance of northern anchovy. During winter 2011/2012, the increased presence of northern copepod species off northern California was consistent with stronger southward transport. Krill and small-fraction zooplankton abundances, where examined, were generally above average. North of 42°N, salps returned to typical abundances in 2012 after greater observed concentrations in 2010 and 2011. In contrast, salp abundance off central and southern California increased after a period of southward transport during winter 2011/2012. Reproductive success of piscivorous Brandt’s cormorant, Phalacrocorax penicillatus, was reduced while planktivorous Cassin’s auklet, Ptychoramphus aleuticus was elevated. Differences between the productivity of these two seabirds may be related to the available forage assemblage observed in the surveys. California sea lion pups from San Miguel Island were undernourished resulting in a pup mortality event perhaps in response to changes in forage availability. Limited biological data were available for spring 2013, but strong winter upwelling coastwide indicated an early spring transition, with the strong upwelling persisting into early summer