BackgroundThe aim of this guideline is to provide updated recommendations for Canadian genetic counsellors, medical geneticists, maternal fetal medicine specialists, clinical laboratory geneticists and other practitioners regarding the use of chromosomal microarray analysis (CMA) for prenatal diagnosis. This guideline replaces the 2011 Society of Obstetricians and Gynaecologists of Canada (SOGC)-Canadian College of Medical Geneticists (CCMG) Joint Technical Update.MethodsA multidisciplinary group consisting of medical geneticists, genetic counsellors, maternal fetal medicine specialists and clinical laboratory geneticists was assembled to review existing literature and guidelines for use of CMA in prenatal care and to make recommendations relevant to the Canadian context. The statement was circulated for comment to the CCMG membership-at-large for feedback and, following incorporation of feedback, was approved by the CCMG Board of Directors on 5 June 2017 and the SOGC Board of Directors on 19 June 2017.Results and conclusionsRecommendations include but are not limited to: (1) CMA should be offered following a normal rapid aneuploidy screen when multiple fetal malformations are detected (II-1A) or for nuchal translucency (NT) ≥3.5 mm (II-2B) (recommendation 1); (2) a professional with expertise in prenatal chromosomal microarray analysis should provide genetic counselling to obtain informed consent, discuss the limitations of the methodology, obtain the parental decisions for return of incidental findings (II-2A) (recommendation 4) and provide post-test counselling for reporting of test results (III-A) (recommendation 9); (3) the resolution of chromosomal microarray analysis should be similar to postnatal microarray platforms to ensure small pathogenic variants are detected. To minimise the reporting of uncertain findings, it is recommended that variants of unknown significance (VOUS) smaller than 500 Kb deletion or 1 Mb duplication not be routinely reported in the prenatal context. Additionally, VOUS above these cut-offs should only be reported if there is significant supporting evidence that deletion or duplication of the region may be pathogenic (III-B) (recommendation 5); (4) secondary findings associated with a medically actionable disorder with childhood onset should be reported, whereas variants associated with adult-onset conditions should not be reported unless requested by the parents or disclosure can prevent serious harm to family members (III-A) (recommendation 8).The working group recognises that there is variability across Canada in delivery of prenatal testing, and these recommendations were developed to promote consistency and provide a minimum standard for all provinces and territories across the country (recommendation 9).

Background:Keratosis pilaris (KP) is characterized by keratinous plugs in the follicular orifices and varying degrees of perifollicular erythema. The most accepted theory of its pathogenesis proposes defective keratinization of the follicular epithelium resulting in a keratotic infundibular plug. We decided to test this hypothesis by doing dermoscopy of patients diagnosed clinically as keratosis pilaris.Materials and Methods:Patients with a clinical diagnosis of KP seen between September 2011 and December 2011 were included in the study. A clinical history was obtained and examination and dermoscopic evaluation were performed on the lesions of KP.Results:The age of the patients ranged from 6-38 years. Sixteen patients had history of atopy. Nine had concomitant ichthyosis vulgaris. All the 25 patients were found to have coiled hair shafts within the affected follicular infundibula. The hair shafts were extracted with the help of a sterile needle and were found to retain their coiled nature. Perifollicular erythema was seen in 11 patients; perifollicular scaling in 9.Conclusion:Based on our observations and previously documented histological data of KP, we infer that KP may not be a disorder of keratinization, but caused by the circular hair shaft which ruptures the follicular epithelium leading to inflammation and abnormal follicular keratinization.

Monosomy 1p36 is an increasingly recognized chromosomal anomaly. We describe two patients with monosomy 1p36 who had brain abnormalities detected on prenatal ultrasound. The first patient was ascertained prenatally with ultrasound abnormalities, including ventriculomegaly, a single umbilical artery, a unilateral club foot, a ventricular septal defect, and intra-uterine growth retardation. Amniocentesis showed a normal karyotype. A postnatal MRI showed moderate to severe non-obstructive hydrocephalus, bilateral colpocephaly, and abnormal myelination of the anterior limb of the internal capsule. A postnatal karyotype demonstrated a deletion of 1p36.3 that was not detected prenatally due to low resolution. Molecular studies by array comparative genome hybridization (CGH) identified a terminal deletion of approximately 10 Mb. Our second patient was a fetus who had brain abnormalities suggestive of holoprosencephaly identified on prenatal ultrasound. Amniocentesis showed 46,XX,der(1)t(1;20)(p36.1;p12.2), that was found to be maternally inherited. Fetal autopsy demonstrated hydrocephalus, focal polymicrogyria, and cerebellar hypoplasia. However, holoprosencephaly was not confirmed. In addition to describing two patients with monosomy 1p36 who had abnormal brain anatomy on prenatal ultrasounds, we review the literature of other prenatally detected patients with monosomy 1p36 and review brain abnormalities seen both prenatally and postnatally.

This is the first LMNA splicing mutation to be associated with FPLD2, and it causes a severe clinical and metabolic phenotype.