Sandra A Farrell

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BACKGROUND Low maternal vitamin B(12) status may be a risk factor for neural tube defects (NTDs). Prior studies used relatively insensitive measures of B(12), did not adjust for folate levels, and were conducted in countries without folic acid food fortification. In Canada, flour has been fortified with folic acid since mid-1997. METHODS We completed a(More)
Speech sound disorders are heterogeneous conditions, and sporadic and familial cases have been described. However, monogenic inheritance explains only a small proportion of such disorders, in particular in cases with childhood apraxia of speech (CAS). Deletions of <5 Mb involving the 12p13.33 locus is one of the least commonly deleted subtelomeric regions.(More)
Microdeletions of 1q43q44 result in a recognizable clinical disorder characterized by moderate to severe intellectual disability (ID) with limited or no expressive speech, characteristic facial features, hand and foot anomalies, microcephaly (MIC), abnormalities (agenesis/hypogenesis) of the corpus callosum (ACC), and seizures (SZR). Critical regions have(More)
The heterogeneity of autism spectrum disorders (ASDs) confounds attempts to identify causes and pathogenesis. Identifiable endophenotypes and reliable biomarkers within ASDs would help to focus molecular research and uncover genetic causes and developmental mechanisms. We used dense surface-modelling techniques to compare the facial morphology of 72 boys(More)
Predictive and pre-natal testing for Huntington's Disease (HD) has been available since 1987. Initially this was offered by linkage analysis, which was surpassed by the advent of the direct mutation test for HD in 1993. Direct mutation analysis provided an accurate test that not only enhanced predictive and pre-natal testing, but also permitted the(More)
Deletions at 2p16.3 involving exons of NRXN1 are associated with susceptibility for autism and schizophrenia, and similar deletions have been identified in individuals with developmental delay and dysmorphic features. We have identified 34 probands with exonic NRXN1 deletions following referral for clinical microarray-based comparative genomic(More)
Simpson-Golabi Behmel syndrome (SGBS) is an X-linked disorder characterized by pre- and postnatal macrosomia, minor facial anomalies, and variable visceral, skeletal, and neurological abnormalities. Since its first description by Simpson et al. [1975: BD:OA XI(2):18-24], a wide clinical range of cases has been reported. There is great variability in(More)
OBJECTIVE To increase primary care providers' awareness and use of genetic services; increase their knowledge of genetic issues; increase their confidence in core genetic competencies; change their attitudes toward genetic testing for hereditary diseases; and increase their confidence as primary care genetic resources. DESIGN Participants completed a(More)
OBJECTIVES To summarise the experience and evaluate the performance of the Ontario maternal serum screening (MSS) programme. SETTING The Ontario MSS programme between October 1993 and September 2000. METHODS This study used information collected in the Ontario MSS database, which contains data on each screened pregnancy. In the Ontario MSS programme,(More)
Three children with deletions involving the 9q22q34 region are described. A review of clinical features of these three new patients and seven previously reported ones did not demonstrate a recognizable dysmorphic pattern. Our cases illustrate the need for repeat karyotyping at higher levels of resolution when there is a suspicion of a chromosome anomaly,(More)