Sandra L. Marles

Manitoba-oculo-tricho-anal (MOTA) syndrome is caused by mutations in FREM1

Background Manitoba-oculo-tricho-anal (MOTA) syndrome is a rare condition defined by eyelid colobomas, cryptophthalmos and anophthalmia/microphthalmia, an aberrant hairline, a bifid or broad nasal tip, and gastrointestinal anomalies such as omphalocele and anal stenosis. Autosomal recessive inheritance had been assumed because of consanguinity in the Oji-Cre population of Manitoba and reports of affected siblings, but no locus or cytogenetic aberration had previously been described. Methods and results This study shows that MOTA syndrome is caused by mutations in FREM1, a gene previously mutated in bifid nose, renal agenesis, and anorectal malformations (BNAR) syndrome. MOTA syndrome and BNAR syndrome can therefore be considered as part of a phenotypic spectrum that is similar to, but distinct from and less severe than, Fraser syndrome. Re-examination of Frem1bat/bat mutant mice found new evidence that Frem1 is involved in anal and craniofacial development, with anal prolapse, eyelid colobomas, telecanthus, a shortened snout and reduced philtral height present in the mutant mice, similar to the human phenotype in MOTA syndrome. Conclusions The milder phenotypes associated with FREM1 deficiency in humans (MOTA syndrome and BNAR syndrome) compared to that resulting from FRAS1 and FREM2 loss of function (Fraser syndrome) are also consistent with the less severe phenotypes resulting from Frem1 loss of function in mice. Together, Fraser, BNAR and MOTA syndromes constitute a clinically overlapping group of FRAS–FREM complex diseases.

Understanding the impact of 1q21.1 copy number variant

Background1q21.1 Copy Number Variant (CNV) is associated with a highly variable phenotype ranging from congenital anomalies, learning deficits/intellectual disability (ID), to a normal phenotype. Hence, the clinical significance of this CNV can be difficult to evaluate. Here we described the consequences of the 1q21.1 CNV on genome-wide gene expression and function of selected candidate genes within 1q21.1 using cell lines from clinically well described subjects.Methods and ResultsEight subjects from 3 families were included in the study: six with a 1q21.1 deletion and two with a 1q21.1 duplication. High resolution Affymetrix 2.7M array was used to refine the 1q21.1 CNV breakpoints and exclude the presence of secondary CNVs of pathogenic relevance. Whole genome expression profiling, studied in lymphoblast cell lines (LBCs) from 5 subjects, showed enrichment of genes from 1q21.1 in the top 100 genes ranked based on correlation of expression with 1q21.1 copy number. The function of two top genes from 1q21.1, CHD1L/ALC1 and PRKAB2, was studied in detail in LBCs from a deletion and a duplication carrier. CHD1L/ALC1 is an enzyme with a role in chromatin modification and DNA damage response while PRKAB2 is a member of the AMP kinase complex, which senses and maintains systemic and cellular energy balance. The protein levels for CHD1L/ALC1 and PRKAB2 were changed in concordance with their copy number in both LBCs. A defect in chromatin remodeling was documented based on impaired decatenation (chromatid untangling) checkpoint (DCC) in both LBCs. This defect, reproduced by CHD1L/ALC1 siRNA, identifies a new role of CHD1L/ALC1 in DCC. Both LBCs also showed elevated levels of micronuclei following treatment with a Topoisomerase II inhibitor suggesting increased DNA breaks. AMP kinase function, specifically in the deletion containing LBCs, was attenuated.ConclusionOur studies are unique as they show for the first time that the 1q21.1 CNV not only causes changes in the expression of its key integral genes, associated with changes at the protein level, but also results in changes in their known function, in the case of AMPK, and newly identified function such as DCC activation in the case of CHD1L/ALC1. Our results support the use of patient lymphoblasts for dissecting the functional sequelae of genes integral to CNVs in carrier cell lines, ultimately enhancing understanding of biological processes which may contribute to the clinical phenotype.

Bowen-Conradi syndrome: a clinical and genetic study.

The purpose of the study was to delineate the anomalies and the natural life history of persons with the Bowen–Conradi syndrome [Bowen and Conradi 1976: Birth Defects: Orig Artic Ser XII(6):101–108]. We ascertained 39 cases and personally examined almost all. For those who were not seen, their clinical record were scrutinized. Pedigree analysis of all 39 was done and kinship coefficients computed. The birth prevalence was estimated to be 1/355 live births.

Trends in Telehealth versus On-site Clinical Genetics Appointments in Manitoba: A Comparative Study

Telehealth involves the use of information and communications technology to deliver health services to patients over distance. Canada is well suited to benefit from telehealth since many individuals live in remote, rural and isolated locations. Manitoba is the easternmost prairie province and MBTelehealth is an active Canadian program that currently has 105 sites in 73 communities. Although studies of patient satisfaction comparing telehealth to on-site clinical visits have been conducted, a comparative study of the types of genetics patients seen via these two modalities has not been performed previously. In this study we: (1) examined the uptake of telehealth in Genetics in Manitoba; (2) contrasted telehealth usage in Genetics with other clinical programs; and (3) performed a comparative study of the types of Genetics referrals seen in 2008 on-site versus via telehealth. Results indicate the uptake of telehealth is increasing and has made genetics outreach clinics unnecessary. The Program of Genetics and Metabolism is consistently one of the top ten utilizers of telehealth within the province. With respect to discipline, chi square analysis revealed the trends were not significantly different for on-site and telehealth encounters, with prenatal referrals being the most common and Hereditary Breast and Ovarian Cancer referrals being the least common. Referrals within each discipline varied depending on the need for fetal assessment and physical examination. Telehealth was utilized regularly for test results sessions across all disciplines.

Manitoba oculotrichoanal (MOTA) syndrome: Report of eight new cases

The Manitoba Oculotrichoanal (MOTA) syndrome was initially described by Marles et al. [1992; Am J Med Genet 42: 793–799] in Aboriginal patients of the Island Lake region of Northern Manitoba. Characteristic findings in affected patients included unilateral upper eyelid coloboma or cryptophthalmus with ipsilateral aberrant anterior hairline pattern and anal anomalies. We describe here seven new patients of the same extended kindred of Cree/Ojibway ethnicity of the Island Lake region and an eighth patient of Caucasian Dutch parents with clinical findings consistent with the diagnosis of MOTA syndrome. Two of the patients have bilateral, instead of unilateral, abnormal anterior hairline patterns. Omphalocele, a feature previously not identified, is present in three of them. The most consistent features appear to be hypertelorism and a broad or notched tip of the nose. Due to the obvious clinical overlap with Fraser syndrome, FRAS1 gene was screened in two of the affected and no mutation was found [Slavotinek et al., submitted].

Humeroradial synostosis, ulnar aplasia and oligodactyly, with contralateral amelia, in a child with prenatal cocaine exposure

Humeral “bifurcation” due to humeroradial synostosis, and amelia are both very rare limb anomalies. We report on a Canadian. Aboriginal boy with both these limb deficiencies. The family history was unremarkable, but he was exposed prenatally to cocaine at the time of limb development. Humeroradial synostosis with ulnar aplasia has been reported by several authors. The majority of cases are unilateral. When both upper limbs arms are involved, cases with oligodactyly often have asymmetrical limb deficiencies and have all been sporadic to date. Some appear to represent cases of the femur–fibula–ulna or FFU complex. Affected individuals with normal hands usually have symmetrical defects and show an autosomal recessive pattern of inheritance. Limb deficiencies have been reported in several infants exposed prenatally to cocaine and have been inducible in animal models. Most are terminal transverse defects or deficiencies of middle digits. When more than one limb is involved, the defects are usually asymmetric. Our case appears to be one of the most severely affected children reported to date.

Cytogenetic microarrays in Manitoba patients with developmental delay

To the Editor: Cytogenetic microarrays have revolutionized conventional cytogenetics by increasing the resolution of the standard karyotype from 5–10 to ,1 Mb using microarray comparative genomic hybridization (aCGH) (1). Targeted microarrays, which cover specific areas of the genome with known clinical significance, and whole genome arrays, which span the entire genome but detect copy number polymorphisms/variants/changes (CNVs) of unknown clinical significance, allow for the comprehensive analysis of hundreds or thousands of distinct genomic loci for DNA copy number losses or gains. Conventional cytogenetics identifies 5–10% abnormalities depending on ascertainment criteria, and microarrays can identify an additional 10–15% of previously undetected abnormalities. The purpose of our study was to determine how many Manitoba patients had unrecognized chromosome imbalances detectable by microarray. Inclusion criteria were unexplained developmental delay (DD) or mental retardation (MR), a normal 550 G-band karyotype, fragile X (FMR1) negative, and at least one of the following additional criteria: multiple congenital anomalies; prenatal growth retardation; postnatal growth abnormalities including microcephaly, short or tall stature, or macrocephaly; facial or non-facial dysmorphisms; or a family history of any of the above clinical criteria in a child with unexplained DD or MR. Exclusion criteria included an identified genetic or environmental diagnosis. A total of 74 children were selected for targeted bacterial artificial chromosome (BAC) microarray analysis using TOP (technical only program) at Combimatrix Molecular Diagnostics (Irvine, CA). The microarray platform used at this time was the CA 1500, which is a targeted array of 1500 BAC clones representing greater than 125 constitutional disorders. All patient microarray abnormalities were confirmed by fluorescent in situ hybridization (FISH); microarray, FISH and karyotype analysis were performed on parents of patients with microarray abnormalities. A total of 7 of 74 (10%) of patients had clinically significant microarray abnormalities, with phenotypes compatible with the specific genomic imbalance observed. The observed frequency is consistent with previous reports (2, 3). These abnormalities are summarized in Table 1. Two of 74 (3%) had unbalanced 1p36 deletions (one interstitial, patient 1; one terminal, patient 2), 2 (3%) (patients 3 and 4) had other subtelomere rearrangements, and the remaining 3 (4%) (patients 5, 6, and 7) had various interstitial deletions. Thus, approximately 5% had subtelomere rearrangements, in agreement with previous estimates (1, 2). Parental microarray studies did not detect any unbalanced cases. However, FISH analyses of the parents of patient 4 (Table 1) showed the presence of a paternal subtelomere translocation: t(12;18)(qter2,pter1;pter2,qter1). In addition, karyotyping the parents of patient 3 (Table 1) fortuitously revealed the presence of a paternal t(1;3)(p36.3;p13), which would not have been otherwise detected as both parents had normal confirmatory subtelomere FISH and microarray results. We recommend confirmatory FISH in all parents of a child with an abnormal microarray result. Parental aCGH may not always be necessary but may be required to provide supportive evidence for the association between a CNV and the clinical presentation. Karyotyping of parents is still recommended for balanced rearrangements. Our targeted microarray study detected 23 the frequency of unbalanced abnormalities as found by conventional karyotyping in our Cytogenetics Laboratory ( 5.4%) (unpublished data) and 103 the full FMR1 mutation in our Molecular Diagnostic Laboratory ( 1%) (unpublished data). Our findings suggest that screening for microarray

Increased Nuchal Translucency Thickness: A Potential Indicator for Ritscher-Schinzel Syndrome

Objective: The Ritscher-Schinzel syndrome (RSS), also known as the 3C syndrome, is an autosomal recessive disorder classically comprising craniofacial, cerebellar and cardiac defects. The underlying molecular etiology remains unknown; therefore, prenatal diagnosis of recurrences depends on identification of the associated structural anomalies on second trimester ultrasound examination. Identification of recurrences using first-trimester ultrasound has not been reported previously. Methods: Two women who presented at our center with fetal nuchal abnormalities on first trimester ultrasound went on to have children with RSS. One of the women had also undergone a previous pregnancy termination for fetal anomalies consistent with RSS. The ultrasound findings and details of these 3 cases were reviewed. Results: Both cases of RSS and the third suspected case were found to have nuchal abnormalities on first-trimester scan. All went on to develop malformations consistent with RSS detectable on second-trimester ultrasound. The later 2 cases continued to term and the children had facial characteristics consistent with RSS. Conclusion: First-trimester ultrasound assessment of nuchal translucency could be considered as a method for identifying sib recurrences of RSS. In addition, RSS should be on the differential diagnosis when increased nuchal translucency is seen on first-trimester scan.

Identification of an uncommon haptoglobin type using DNA and protein analysis

The inherited variations in haptoglobin phenotypes are attributed to the homozygous and heterozygous combinations of three common autosomal alleles:HP*1F,HP*1S andHP*2.HP*1F andHP*1S encode polypeptides that differ by two amino acids at positions 51 and 53. The formation ofHP*2 is postulated to have resulted from a breakage and subsequent reunion event at non-homologous positions of twoHP*1 alleles. The most common form ofHP*2 isHP*2FS in which the 5′ end ofHP*2 resemblesHP*1F and the 3′ end resemblesHP*1S. Homologous crossing over betweenHP*2 and either anHP*1F orHP*1S allele inHP*2/HP*1 heterozygotes can change the usual type ofHP*2 to three other forms:HP*2SS,HP*2FF orHP*2SF. We describe a nuclear family in which the uncommon genotypeHP*2SS in one parent caused initial confusion in assigning genotypes to the rest of the nuclear family. The data demonstrate the need for a cautious approach when deducing haptoglobin genotypes from molecular analysis alone.

Ataxia-telangiectasia with female fertility.

Ataxia-Telangiectasia with Female Fertility Angelika J. Dawson,* Sandra Marles, Michelle Tomiuk, Diane Riordan, and Richard A. Gatti Cytogenetic Laboratory/HSC, Diagnostic Services of Manitoba, Winnipeg, Manitoba, Canada Deptartments of Biochemistry & Medical Genetics and Pediatrics & Child Health, University of Manitoba, Winnipeg, Manitoba, Canada Genetics & Metabolism Program, WRHA, Winnipeg, Manitoba, Canada Department of Pathology & Laboratory Medicine, and Human Genetics, UCLA/Geffen School of Medicine, Los Angeles, California