Missense mutations in ITPR1 cause autosomal dominant congenital nonprogressive spinocerebellar ataxia.

BACKGROUND: Congenital nonprogressive spinocerebellar ataxia is characterized by early gross motor delay, hypotonia, gait ataxia, mild dysarthria and dysmetria. The clinical presentation remains fairly stable and may be associated with cerebellar atrophy. To date, only a few families with autosomal dominant congenital nonprogressive spinocerebellar ataxia have been reported. Linkage to 3pter was demonstrated in one large Australian family and this locus was designated spinocerebellar ataxia type 29. The objective of this study is to describe an unreported Canadian family with autosomal dominant congenital nonprogressive spinocerebellar ataxia and to identify the underlying genetic causes in this family and the original Australian family. METHODS AND RESULTS: Exome sequencing was performed for the Australian family, resulting in the identification of a heterozygous mutation in the ITPR1 gene. For the Canadian family, genotyping with microsatellite markers and Sanger sequencing of ITPR1 gene were performed; a heterozygous missense mutation in ITPR1 was identified. CONCLUSIONS: ITPR1 encodes inositol 1,4,5-trisphosphate receptor, type 1, a ligand-gated ion channel that mediates calcium release from the endoplasmic reticulum. Deletions of ITPR1 are known to cause spinocerebellar ataxia type 15, a distinct and very slowly progressive form of cerebellar ataxia with onset in adulthood. Our study demonstrates for the first time that, in addition to spinocerebellar ataxia type 15, alteration of ITPR1 function can cause a distinct congenital nonprogressive ataxia; highlighting important clinical heterogeneity associated with the ITPR1 gene and a significant role of the ITPR1-related pathway in the development and maintenance of the normal functions of the cerebellum.

Maternal factor V Leiden and adverse pregnancy outcome: deciding whether or not to test.

This narrative review examines the translation from statistical association to change in clinical practice with respect to factor V Leiden and adverse pregnancy outcome. A collation of published meta-analyses illustrates a clear trend towards a greater association with factor V Leiden (fVL) as the severity of adverse pregnancy outcomes increases, and highlights that different study populations are relevant to different clinical scenarios. The yield of fVL testing in women with previous adverse pregnancy outcomes is up to six times higher than in the general population. Calculated post-test probabilities illustrate that the combined effect of fVL and poor pregnancy history places these women at a high-risk of recurrent events. The results to date of low molecular weight heparin (LMWH) treatment trials cannot be extrapolated to all women with thrombophilia; however, the results provide a rationale for randomized prophylactic anticoagulant treatment trials in thrombophilic women with severe adverse pregnancy outcomes. While we await the results of well-designed, adequately powered treatment trials, we propose that post-test probabilities, in addition to the preliminary treatment data in high-risk women, justify consideration of screening for fVL in women with a strong past history of poor pregnancy outcome.

Lessons from the skin--cutaneous features of familial cancer.

As the molecular basis of disease continues to be elucidated, familial cancer syndromes, which consist of a range of neoplastic and non-neoplastic features, are emerging. The usual pathway of referral to a genetics clinic or familial cancer centre is via an oncologist, when high-risk features that suggest a possible hereditary basis for the presenting cancer are recognised. Traditionally, these high-risk features include more than two family members with similar cancers over two or more generations, a young age of onset, and more than one synchronous or metachronous tumour. These features are effective in ascertaining a substantial proportion of families with hereditary breast and ovarian cancer due to a BRCA mutation, or the more common bowel-cancer predisposition syndromes, such as hereditary non-polyposis colon cancer and familial adenomatous polyposis. However, there are a range of familial cancer syndromes that are not easily detected and that can remain undiagnosed when history and examination are not extended to include non-malignant features. The identification of cutaneous signs associated with rare familial-cancer syndromes provides individuals and their families with the opportunity to undertake early surveillance for malignant and non-malignant complications that might in time be shown to improve outcomes.

Screening behavior in women at increased familial risk for breast cancer.

This multicenter study examined the adherence of high-risk women to screening recommendations for breast and ovarian cancer following consultation at a familial cancer clinic (FCC). Self-report questionnaires assessing recall of screening advice, tests undertaken, risk perception, anxiety (Impact of Events Scale) and demographics were mailed to 396 consecutive eligible women who had attended one of six FCCs a median of 3.6 years prior. Family history, genetic test results and screening recommendations were abstracted from medical records. 182/266 (68.4%) women responded with 130 lost to follow-up. The proportions of women undertaking at least the recommended frequency of screening tests were: breast self examination (BSE) 50.4%, clinical breast examination (CBE) 66.0%, mammography 82.2%, transvaginal ultrasound (TVUS) 70.0%, CA125 84.0%. Factors associated with adherence to screening were: higher anxiety for BSE and CBE, being BRCA1/2 positive for CBE, older age, method of arrangement and having at least one affected first degree relative for mammography. Factors significantly associated with over-adherence were higher scores for anxiety for BSE and CBE and younger age (< 40 years) for TVUS. Between 41.3% (BSE) and 57.6% (CBE) of women incorrectly recalled their screening recommendations. A substantial minority of high-risk women do not adhere to screening advice. Strategies to improve the accuracy of recall of recommendations and the uptake of recommended screening are required.

The association between adverse pregnancy outcomes and maternal factor V Leiden genotype: a meta-analysis.

The conclusions of studies to date which evaluate a possible association between factor V Leiden and adverse pregnancy outcome have been conflicting. This study was undertaken to further investigate this association. Our objective was to evaluate the association between adverse pregnancy outcomes and maternal factor V Leiden genotype by meta-analysis. Inclusion criteria were: (a) cohort or case control design; (b) outcomes clearly defined as one of the following: first or second/ third trimester miscarriage or intrauterine death, preeclampsia, fetal growth retardation, or placental abruption; (c) both the case and control mothers tested for the factor V Leiden mutation; (d) sufficient data for calculation of an odds ratio. Both fixed and random effect models were used to pool results and heterogeneity and publication bias were checked. For first trimester fetal loss, the pooled odds ratio was heterogeneous (p=0.06) and no dose-response curve could be found. For second/third trimester fetal loss, there was a consistent and graded increase in risk: the odds ratio was 2.4 (95% CI 1.1-5.2) for isolated (non-recurrent) third trimester fetal loss, rising to 10.7 (95% CI 4.0-28.5) for those with 2 or more second/third trimester fetal losses. Factor V Leiden is associated with a 2.9 fold (95% CI 2.0-4.3) increased risk of severe preeclampsia, and a 4.8 fold (95% CI 2.4-9.4) increased risk of fetal growth retardation. These results support factor V Leiden testing for women with recurrent fetal loss in the second/third trimester. Women with only 1 event may also warrant testing if the fetal loss occurred in the third trimester. Conversely, in those women known to have the factor V Leiden mutation, monitoring for adverse pregnancy outcomes is warranted; whether this means increased vigilance or anti-coagulant prophylaxis is still contentious.