Maternal age and the risk of fetal aneuploidy: A nationwide cohort study of more than 500 000 singleton pregnancies in Denmark from 2008 to 2017.

INTRODUCTION: In this register-based study of pregnancies in Denmark, we assessed the associations between maternal age and the risk of fetal aneuploidies (trisomy 21, trisomy 18, trisomy 13, triploidy, monosomy X and other sex chromosome aberrations). Additionally, we aimed to disentangle the maternal age-related effect on fetal aneuploidies by cases with translocation trisomies and mosaicisms. MATERIAL AND METHODS: We followed a nationwide cohort of 542 375 singleton-pregnant women attending first trimester screening in Denmark between 2008 and 2017 until delivery, miscarriage or termination of pregnancy. We used six maternal age categories and retrieved information on genetically confirmed aneuploidies of the fetus and infant from the national cytogenetic register. RESULTS: We confirmed the known associations between advanced maternal age and higher risk of trisomy 21, 18, 13 and other sex chromosome aberrations, especially in women aged ≥35 years, whereas we found no age-related associations with triploidy or monosomy X. Cases with translocation trisomies and mosaicisms did not influence the overall reported association between maternal age and aneuploidies. CONCLUSION: This study provides insight into the accurate risk of fetal aneuploidies that pregnant women of advanced ages encounter.

Preimplantation genetic testing in two Danish couples affected by Peutz-Jeghers syndrome.

BACKGROUND: Guidelines from the European Hereditary Tumor Group as well as The Danish National Guidelines for Peutz-Jeghers Syndrome (PJS) state that both prenatal diagnosis and preimplantation genetic testing for monogenic disorders (PGT-M) should be offered to patients with PJS. However, only a few cases resulting in viable pregnancies have been published. OBJECTIVE: We present two cases of PJS patients going through PGT-M for PJS. We highlight the awareness of this possibility and discuss the technical and ethical challenges of performing PGT-M for PJS. METHODS AND RESULTS: Case 1: A 36-year-old male with PJS and his partner were referred for genetic counseling. The patient carried a pathogenic de novo variant in STK11. After a terminated pregnancy of a fetus carrying the same pathogenic variant, microsatellite polymorphic marker analysis was established, and the patient was offered PGT-M. The female partner of the patient gave birth to a healthy boy after five years of fertility treatment. Case 2: A 35-year-old female with PJS and her partner were referred for genetic counseling. She carried an inherited pathogenic STK11 variant. The couple was offered PGT-M. Genetic testing of the embryos was performed using microsatellite polymorphic markers. After two rounds of oocyte extraction a blastocyst predicted not to be affected by PJS was identified. The blastocyst was transferred; however, this did not result in a viable pregnancy. CONCLUSIONS: PGT-M can be offered to patients with PJS. The process may be long and filled with ethical dilemmas requiring patients to be motivated and persistent.

Causes of poor eye contact in infants: a population-based study.

BACKGROUND: Establishing eye contact between infants and parents is important for early parent-child bonding and lack of eye contact may be a sign of severe underlying disease. The aim of the study was to evaluate the causes of poor or lacking eye contact in infants. METHODS: Cross-sectional study reviewing all referrals of infants ≤1 year of age from January 1rst, 2016 to December 31rst, 2018. Medical information was retrieved from patient files covering pregnancy, birth, diagnostic work-up and ocular parameters such as refraction, visual acuity and structural findings. RESULTS: We identified 99 infants with poor or lacking eye contact. The relative frequency of causes was neurologic disease 36.4% (36/99), delayed visual maturation 24.2% (24/99), ocular disease 21.2% (21/99) and idiopathic infantile nystagmus 4.0% (4/99). Fourteen infants had a visual function within age-related norms at first examination despite poor eye contact at the time of referral. Of the infants with available data, 18/27 (33.3%) with neurologic cause, 15/23 (65.2%) with delayed visual maturation and 9/21 (42.9%) with ocular cause had visual acuity within the age-related norm at latest follow-up (0-41 months). In 23 infants, a genetic cause was found. CONCLUSION: Poor eye contact in infants may be a sign of severe underlying disease, such as neurological or ocular disease. Close collaboration between pediatric ophthalmologists and neuro-pediatricians are warranted in the management of these infants.

Case report: a novel KERA mutation associated with cornea plana and its predicted effect on protein function.

BACKGROUND: Cornea plana (CNA) is a hereditary congenital abnormality of the cornea characterized by reduced corneal curvature, extreme hypermetropia, corneal clouding and hazy corneal limbus. The recessive form, CNA2, is associated with homozygous or compound heterozygous mutations of the keratocan gene (KERA) on chromosome 12q22. To date, only nine different disease-associated KERA mutations, including four missense mutations, have been described. CASE PRESENTATION: In this report, we present clinical data from a Turkish family with autosomal recessive cornea plana. In some of the affected individuals, hypotrichosis was found. KERA was screened for mutations using Sanger sequencing. We detected a novel KERA variant, p.(Ile225Thr), that segregates with the disease in the homozygous form. The three-dimensional structure of keratocan protein was modelled, and we showed that this missense variation is predicted to destabilize the structure of keratocan, leading to the classical ocular phenotype in the affected individuals. All the four known missense mutations, including the variation found in this family, affect the conserved residues of the leucine rich repeat domain of keratocan. These mutations are predicted to result in destabilization of the protein. CONCLUSION: We present the 10th pathogenic KERA mutation identified so far. Protein modelling is a useful tool in predicting the effect of missense mutations. This case underline the importance of the leucin rich repeat domain for the protein function, and this knowledge will ease the interpretation of future findings of mutations in these areas in other families with cornea plana.

Refinement of genotype-phenotype correlation in 18 patients carrying a 1q24q25 deletion.

Interstitial deletion 1q24q25 is a rare rearrangement associated with intellectual disability, growth retardation, abnormal extremities and facial dysmorphism. In this study, we describe the largest series reported to date, including 18 patients (4M/14F) aged from 2 days to 67 years and comprising two familial cases. The patients presented with a characteristic phenotype including mild to moderate intellectual disability (100%), intrauterine (92%) and postnatal (94%) growth retardation, microcephaly (77%), short hands and feet (83%), brachydactyly (70%), fifth finger clinodactyly (78%) and facial dysmorphism with a bulbous nose (72%), abnormal ears (67%) and micrognathia (56%). Other findings were abnormal palate (50%), single transverse palmar crease (53%), renal (38%), cardiac (38%), and genital (23%) malformations. The deletions were characterized by chromosome microarray. They were of different sizes (490 kb to 20.95 Mb) localized within chromosome bands 1q23.3-q31.2 (chr1:160797550-192912120, hg19). The 490 kb deletion is the smallest deletion reported to date associated with this phenotype. We delineated three regions that may contribute to the phenotype: a proximal one (chr1:164,501,003-167,022,133), associated with cardiac and renal anomalies, a distal one (chr1:178,514,910-181,269,712) and an intermediate 490 kb region (chr1:171970575-172460683, hg19), deleted in the most of the patients, and containing DNM3, MIR3120 and MIR214 that may play an important role in the phenotype. However, this genetic region seems complex with multiple regions giving rise to the same phenotype.

Variants in the WDR44 WD40-repeat domain cause a spectrum of ciliopathy by impairing ciliogenesis initiation.

WDR44 prevents ciliogenesis initiation by regulating RAB11-dependent vesicle trafficking. Here, we describe male patients with missense and nonsense variants within the WD40 repeats (WDR) of WDR44, an X-linked gene product, who display ciliopathy-related developmental phenotypes that we can model in zebrafish. The patient phenotypic spectrum includes developmental delay/intellectual disability, hypotonia, distinct craniofacial features and variable presence of brain, renal, cardiac and musculoskeletal abnormalities. We demonstrate that WDR44 variants associated with more severe disease impair ciliogenesis initiation and ciliary signaling. Because WDR44 negatively regulates ciliogenesis, it was surprising that pathogenic missense variants showed reduced abundance, which we link to misfolding of WDR autonomous repeats and degradation by the proteasome. We discover that disease severity correlates with increased RAB11 binding, which we propose drives ciliogenesis initiation dysregulation. Finally, we discover interdomain interactions between the WDR and NH2-terminal region that contains the RAB11 binding domain (RBD) and show patient variants disrupt this association. This study provides new insights into WDR44 WDR structure and characterizes a new syndrome that could result from impaired ciliogenesis.

The duplication 17p13.3 phenotype: analysis of 21 families delineates developmental, behavioral and brain abnormalities, and rare variant phenotypes.

Chromosome 17p13.3 is a gene rich region that when deleted is associated with the well-known Miller-Dieker syndrome. A recently described duplication syndrome involving this region has been associated with intellectual impairment, autism and occasional brain MRI abnormalities. We report 34 additional patients from 21 families to further delineate the clinical, neurological, behavioral, and brain imaging findings. We found a highly diverse phenotype with inter- and intrafamilial variability, especially in cognitive development. The most specific phenotype occurred in individuals with large duplications that include both the YWHAE and LIS1 genes. These patients had a relatively distinct facial phenotype and frequent structural brain abnormalities involving the corpus callosum, cerebellar vermis, and cranial base. Autism spectrum disorders were seen in a third of duplication probands, most commonly in those with duplications of YWHAE and flanking genes such as CRK. The typical neurobehavioral phenotype was usually seen in those with the larger duplications. We did not confirm the association of early overgrowth with involvement of YWHAE and CRK, or growth failure with duplications of LIS1. Older patients were often overweight. Three variant phenotypes included cleft lip/palate (CLP), split hand/foot with long bone deficiency (SHFLD), and a connective tissue phenotype resembling Marfan syndrome. The duplications in patients with clefts appear to disrupt ABR, while the SHFLD phenotype was associated with duplication of BHLHA9 as noted in two recent reports. The connective tissue phenotype did not have a convincing critical region. Our experience with this large cohort expands knowledge of this diverse duplication syndrome.

Epidemiology of ectopia lentis and outcomes after surgery in a Danish population.

PURPOSE: To describe the causes of ectopia lentis (EL) and the outcomes after surgery in a Danish population. SETTING: The Eye Clinic Rigshospitalet and Kennedy Center in Copenhagen. DESIGN: Retrospective cohort study. METHODS: Medical records of patients with nontraumatic EL born after 1980 and seen at the Eye Clinic Rigshospitalet and Kennedy Center from 1983 to 2019 were reviewed. Clinical information regarding family history, comorbidities, genetic workup, ophthalmological examinations, and surgical history was retrieved. RESULTS: 72 patients (38 males), of whom 68 had bilateral EL (94.4%) were identified. Marfan syndrome (MFS) was found in 34 (47.2%) and biallelic variants in ADAMTSL4 in 4 (5.6%). Surgery was performed in 38 (52.8%) patients, 66 eyes, with a median age at the time of first eye surgery of 8.4 years (range 0.8 to 39.0 years) and a follow-up of 2.3 years (range 0 to 25.7 years). Intraocular lenses were implanted in 9 (23.7%) (11 eyes). Corrected distance visual acuity improved from 0.7 to 0.2 logMAR (median) in right eyes and from 0.7 to 0.3 logMAR in left eyes postoperatively. 21 patients (56.8%), 42 eyes, did not experience any surgery-related complications. 3 patients (3 eyes) experienced a perioperative tear in the posterior capsule. Temporary postoperative ocular hypertension was reported in 3 patients (7.9%) (3 eyes), and 2 patients (5.4%) (2 eyes) developed persistent ocular hypertension. There were no cases of postoperative retinal detachment. CONCLUSIONS: The main reason for EL was MFS. Surgery improved visual acuity, and postoperative ocular hypertension was the most common complication, whereas retinal detachment was not observed.

Genetic disease is a common cause of bilateral childhood cataract in Denmark.

Purpose: Bilateral childhood cataracts can be caused by a metabolic disease, constitute a part of a syndrome, run in families, be sporadic or iatrogenic. The amount of work-up needed to establish a cause is discussed and the aim of the present study was to evaluate causes of bilateral childhood cataract.Methods: Chart review of 211 Danish children with bilateral cataracts. Information on work-up was retrieved with special focus on general health, metabolic screening, evaluation for congenital infections and genetic testing.Results: Cataract was seen in combination with systemic disease in 40.8%, 29.4% had hereditary cataracts, 27.0% had isolated cataract, in 1.4% it was associated with ocular malformations and 1.4% had been born prematurely without any other sequelae than the cataract. A genetic cause could be demonstrated in 74 children.Conclusion: Systemic comorbidities are very common in children with cataract and are not always known prior to the diagnosis of cataract. Genetic evaluation, especially targeted analyses, provided a molecular genetic diagnosis in a large proportion of those tested but it also failed to provide a molecular genetic diagnosis in some patients with a family history suggesting autosomal dominant inheritance. Most importantly, in some patients, genetic work-up provided a diagnosis in patients where it had therapeutic consequences and where the systemic disease would have caused irreversible damage, had it not been treated timely. Given the high prevalence of systemic disease, it seems advisable to co-manage children with bilateral cataracts with a pediatrician and to include genetic evaluation as part of the work-up.

[Genetic screening of adopted individuals].

Information regarding hereditary disease predisposition is generally inaccessible for adoptees. The lack of family history restricts access to various surveillance programmes and the overall health of the adoptee. Genetic screening of asymptomatic adoptees could be a compensational tool. However, variant classification is difficult, even more so in certain ethnic groups and in cases where there is no knowledge of family history, as summarised in this review. The usefulness of genetic screening of asymptomatic adoptees is still unknown and requires further research for clarification.

[Genetic screening of prospective parents].

Risk of genetic diseases with autosomal recessive or X-linked inheritance can be unknown to prospective parents until an affected child is born. New technology has enabled carrier screening for hundreds of genetic diseases (expanded carrier screening, ECS). I Denmark, each year estimated 100-180 children are born affected with a serious condition which could have been detected with ECS of the parents. This review describes the considerations and perspectives of a systematic genetic screening programme for prospective parents in the Danish healthcare system.

Direct to consumer genetic testing in Denmark-public knowledge, use, and attitudes.

Direct to consumer genetic testing (DTC-GT) is offered by commercial companies, but the use in the general population has only been sparsely investigated. A questionnaire was sent to 2013 representative Danish citizens asking about their awareness and use of DTC-GT. Individuals who had undergone a genetic test were interviewed to determine if the results had been understood correctly. A pilot study with 2469 questionnaires was performed before this study. In total, 45.4% of the individuals (n = 913/2013) had knowledge about DTC-GT and 2.5% (n = (18 + 5)/913) previously had a genetic test by a private company and 5.8% through the public health care system (n = (48 + 5)/913). Curiosity about own genetic information was the most frequent motivation (40.9%, n = 9/22) as well as knowledge of ancestry (36.4%, n = 8/22) and advice about lifestyle, exercise, or diet (36.4%, n = 8/22). Test of own disease risk was given as a reason in 27.3% (n = 6/22) and seeking possible explanation of specific symptoms in 13.6% (n = 3/22). 50% (n = 11/22) answered that they had become concerned after the test, and 17.4% (n = 4/23) had consulted their GP. Interviews in a subset of respondents from the pilot study revealed problems with understanding the results. One problem was how to interpret the genetic test results with respect to individual risk for a disease. For example, the difference between disease causing genetic variants in monogenetic diseases versus statistical risks by SNPs in multifactorial diseases was not understood by the respondents.

[Preimplantation genetic testing].

Preimplantation genetic testing (PGT) for known familial monogenetic disease (PGT-M) or structural chromosomal rearrangements (PGT-SR) has evolved into a well-established alternative to prenatal diagnosis. PGT significantly reduces the risk of a pregnancy with an affected foetus. Screening for aneuploidy (PGT-A) used as an add-on to standard IVF treatment of infertile couples is widely used internationally, although its benefit is highly debated. PGT combines genetic counselling and testing with assisted reproductive technology including ovarian stimulation, egg retrieval, and embryo biopsy, as discussed in this review.

Preimplantation Genetic Testing of Multiple Endocrine Neoplasia Type 2A.

Background: When discussing matters of reproduction, the 2015 revised guidelines for the management of medullary thyroid carcinoma recommend that patients diagnosed with multiple endocrine neoplasia type 2A (MEN 2A) are informed about the option of Preimplantation Genetic Testing for Monogenic Disorders (PGT-M). In addition, patients seem to have a genuine interest in reproductive options. However, there are just two reports worldwide of this technology being used for patients with MEN 2A. We here present, in a Danish couple where the man has MEN 2A, the first European family with children born after PGT-M. Objective: To report the results of PGT-M in relation to multiple endocrine neoplasia type 2A with the aim to increase awareness among physicians treating this and other genetic disorders. Methods: A Danish couple was referred to the PGT Center at Copenhagen University Hospital Rigshospitalet and opted for PGT-M after counseling by a clinical geneticist and a fertility doctor. The embryos were diagnosed using microsatellite polymorphic marker close to RET. Results: The couple had two healthy children born in 2017 and 2019 as a result of a total of three ICSI treatments including controlled ovarian stimulation, oocyte retrieval and PGT-M, and a total of six blastocyst transfers. Conclusion: A session with a clinical geneticist covering all reproductive options for patients in early adult life is a relevant part of the clinical management of patients with MEN 2A, and other patients with hereditary cancer predisposition syndromes.

Prevalence and causes of infantile nystagmus in a large population-based Danish cohort.

PURPOSE: The aim of this study was to provide a population-based estimate on the prevalence of infantile nystagmus and to describe the causes in the Capital Region of Denmark. METHODS: Review of medical records of children with infantile nystagmus born in the period 1 January 2010 through 31 December 2017 and living in the Capital Region of Denmark. We used birth registry data from Statistics Denmark and the National Danish Birth Registry to calculate the prevalence of nystagmus in children born at term and prematurely. RESULTS: A total of 103 patients (52 males/51 females) with infantile nystagmus were included. The overall prevalence of infantile nystagmus was 6.1 per 10 000 live births. It was higher in premature children (28.4/10 000 live births) than children born at term (4.4/10 000), p < 0.0001, and highest in children born extremely preterm, (97.3/10 000). The most common cause of infantile nystagmus was ocular disease (44%) followed by idiopathic nystagmus (32%), neurological disorders and genetic syndromes (20%) and prematurity without retinopathy of prematurity as the only cause (4%). CONCLUSIONS: In this study, we provide the prevalence of infantile nystagmus based on national medical records in which all residents are accounted for. Our findings show a prevalence of 6.1 per 10 000 live births but six times higher among children born preterm than born at term. Ocular disease was the leading cause of infantile nystagmus with albinism and ocular malformations as the most frequent. In 1/3 of patients, no cause could be identified.

[Preimplantation genetic testing for aneuploidy].

This review summarises the current knowledge on preimplantation genetic testing for aneuploidy (PGT-A). Selection and transfer of euploid embryos aim to improve live birth rate (LBR) per embryo transfer, but fluorescence in situ hybridisation-based PGT-A and biopsy of cleavage stage embryos in the 2000s was a disappointment, as studies revealed a reduced LBR. Today, PGT-A includes comprehensive chromosome screening primarily of blastocyst biopsies. The benefit of PGT-A is highly debated: some suggest improved treatment outcome, while others claim, that the procedure is not cost-effective.

Is MED13L-related intellectual disability a recognizable syndrome?

INTRODUCTION: MED13L-related intellectual disability is characterized by moderate intellectual disability (ID), speech impairment, and dysmorphic facial features. We present 8 patients with MED13L-related intellectual disability and review the literature for phenotypical and genetic aspects of previously described patients. MATERIALS AND METHODS: In the search for genetic aberrations in individuals with ID, two of the patients were identified by chromosomal microarray analysis, and five by exome sequencing. One of the individuals, suspected of MED13L-related intellectual disability, based on clinical features, was identified by Sanger sequencing. RESULTS: All 8 individuals had de novo MED13L aberrations, including two intragenic microdeletions, two frameshift, three nonsense variants, and one missense variant. Phenotypically, they all had intellectual disability, speech and motor delay, and features of the mouth (open mouth appearance, macroglossia, and/or macrostomia). Two individuals were diagnosed with autism, and one had autistic features. One had complex congenital heart defect, and one had persistent foramen ovale. The literature was reviewed with respect to clinical and dysmorphic features, and genetic aberrations. CONCLUSIONS: Even if most clinical features of MED13L-related intellectual disability are rather non-specific, the syndrome may be suspected in some individuals based on the association of developmental delay, speech impairment, bulbous nasal tip, and macroglossia, macrostomia, or open mouth appearance.

Risk of Adverse Pregnancy Outcomes at Advanced Maternal Age.

OBJECTIVE: To study the possible associations between advanced maternal age and risk of selected adverse pregnancy outcomes. METHODS: The study used a nationwide cohort of 369,516 singleton pregnancies in Denmark followed from 11-14 weeks of gestation to delivery or termination of pregnancy. Pregnant women aged 35 years or older were divided into two advanced maternal age groups, 35-39 years and 40 years or older, and compared with pregnant women aged 20-34 years. Adverse pregnancy outcomes were chromosomal abnormalities, congenital malformations, miscarriage, stillbirth, and birth before 34 weeks of gestation. Multivariable logistic regression analyses were performed to investigate associations between advanced maternal age and adverse pregnancy outcomes. Furthermore, a risk prediction model for a composite adverse pregnancy outcome was made with prespecified predicting factors. RESULTS: Among the pregnant women aged 40 years or older, 10.82% experienced one or more of the selected adverse pregnancy outcomes compared with 5.46% of pregnant women aged 20-34 years (odds ratio [OR] 2.02, 99.8% CI 1.78-2.29). When pregnant women 40 years or older were compared with women aged 20-34 years, they had a higher risk of chromosomal abnormalities (3.83% vs 0.56%, OR 7.44 [CI 5.93-9.34]), miscarriage (1.68% vs 0.42%, OR 3.10 [CI 2.19-4.38]), and birth before 34 weeks of gestation (2.01% vs 1.21%, OR 1.66 [CI 1.23-2.24]), but no increased risk of congenital malformations and stillbirth. The risk prediction chart showed that advanced maternal age, use of assisted reproductive technology, nulliparous pregnancy, smoking during pregnancy, and obesity increased the absolute predictive risk of an adverse pregnancy outcome. CONCLUSION: Women older than 40 years have a higher risk of chromosomal abnormalities, miscarriage, and birth before 34 weeks of gestation than younger women and should be monitored accordingly. No increased risk was observed for stillbirth and other congenital malformations. Several factors increase the risk of adverse pregnancy outcomes, but advanced maternal age drives a high proportion of the total risk score.

Congenital Microphthalmia, Anophthalmia and Coloboma among Live Births in Denmark.

PURPOSE: This study aims to quantify the occurrence of the congenital eye malformations anophthalmia (AO), microphthalmia (MO) and coloboma among liveborn infants in Denmark, and to estimate the rate of chromosomal abnormalities in this group of patients. METHODS: A cohort of patients born in 1995-2012 with diagnoses of MO/AO or coloboma was identified from the Danish National Patient Registry (DNPR), and their ocular and extra-ocular diagnoses were reviewed. In order to assess the occurrence of chromosomal abnormalities in the cohort, the data were cross-referenced with the Danish Cytogenetic Central Registry (DCCR). RESULTS: We identified 415 patients with MO/AO/coloboma in the DNPR. The total number of live births from 1995-2012 was 1,174,299, and the average birth prevalence of MO/AO/coloboma was 3.6/10,000 live births and of MO/AO was 1.2/10,000 live births. Extra-ocular abnormalities were observed in 32.1% of MO/AO cases and 21.7% of coloboma cases. Chromosome analysis was performed in 36.1% of the cohort, and 14.7% of cases had an abnormal karyotype. In 8.7% of the cohort, a chromosome microarray analysis was performed, and in 44.4% of cases, a possibly pathogenic copy number variation was observed. CONCLUSION: The birth prevalence of MO/AO/coloboma in Denmark has been steady at 3.6/10,000 live births during the last 17 years. The rate of syndromic cases was lower compared to other studies. A relatively high rate of pathogenic chromosomal aberrations was observed, suggesting an important role for cytogenetic analysis in this group of patients.

[Pontocerebellar hypoplasia is a rare cause of floppy infant syndrome]. / Pontocerebellar hypoplasi er en sjælden årsag til slapt spædbarn.

The hypotone neonate, floppy infant, often proves to be a diagnostic challenge, as the causes of floppy infant syndrome are many and often rare. In this case story a floppy girl was diagnosed with the rare, autosomal recessive disease pontocerebellar hypoplasia type I. The tests for the most common causes of floppy infant syndrome showed nothing abnormal, but an array comparative genomic hybridization test gave information of loss of heterozygosity. This helped to narrow the list of plausible diagnoses and eventually led to the diagnosis of pontocerebellar hypoplasia type I.