Educational tools support informed decision-making for genetic carrier screening in a heterogenic Israeli population.

Reproductive genetic carrier screening (RGCS) aims to provide couples with information to make informed decisions. Since 2013, the Israeli Carrier Screening Program has been offered routinely and free of charge to all Israelis of reproductive age, personalized based on religion, ethnicity, and village/tribe where a disorder is frequent. This study evaluated the impact of two educational tools on an informed choice on RGCS uptake and satisfaction with counselling within a heterogeneous population in northern Israel. Participants from diverse sociodemographic population groups were randomly assigned to watch an animated film, read a booklet conveying the same information, or receive no information before counselling for RGCS, and asked to complete pre- and post-counselling questionnaires. A higher informed-decision rate was demonstrated in the film (n=93/141, 66%) and booklet (n=88/131, 67%) groups vs. the non-intervention group (n=62/143, 43%) (P<0.001), assessed by the Multidimensional Measure of Informed Choice. Multivariate logistic regression analysis revealed that allocation to an intervention group, Jewish ethnicity and higher education level, best predicted informed choice. Most participants expressed high levels of satisfaction with the counselling process, regardless of group assignment. While only a minority of participants reported seeking information prior to visiting the clinic, the pre-counselling information interventions were well accepted. Pre-counselling self-learning educational tools should be promoted, easily available, and adjusted linguistically and culturally to targeted populations, to avoid unwanted "automatic" compliance of tested individuals and maximize the potential of informed decision-making. Our study can be applied to other countries where majority and minority ethnic groups access genetic services.

The effect of a prior e-learning tool on genetic counseling outcomes in diverse ethnic couples with abnormal Down syndrome screening tests: A randomized controlled trial.

Genetic counseling (GC) following abnormal Down syndrome (DS) screening tests aims to ensure learning of complex medical concepts and discussion of counselees' personal desires. Pre-GC use of electronic learning tools (e-learning tools) can facilitate GC sessions by allowing more time for dialogue rather than learning medical and genetic concepts, enabling greater focus on the counselee's decisional, psychological, and personal needs. Few studies have investigated such tools for DS screening tests and those who have focused on screening uptake rather than abnormal results and implications. This study evaluated prenatal GC outcomes following implementation of an e-learning tool utilizing an educational animated movie for couples of varied ethnic backgrounds in northern Israel, with abnormal DS screening tests. E-learning tool impact was assessed as knowledge level, informed choices, satisfaction with the intervention and GC process, the state of anxiety and duration of the GC meeting. The 321 study participants were randomized to three groups: animation movie, booklet, and control. All participants had been asked to complete pre- and post-counseling questionnaires. Outcome scores were compared between the research groups. Results showed increased knowledge level in general among participants in the animation group; among minority participants, the highest knowledge level was in the animation group. Anxiety levels and informed choices were not statistically different among the groups. However, watching the animation, Jewish ethnicity, good level of genetic literacy, and academic degree were significant predictors of informed choice, and those who watched the animation were three times more likely to make an informed choice than the control group. Our findings suggest that this e-learning tool is efficient and acceptable for the general population. Special attention is needed for minorities with lower genetic literacy and education.

The landscape of autosomal recessive variants in an isolated community: Implications for population screening for reproductive purposes.

As a result of the preference for consanguineous/endogamous marriages, the Israeli Arab population is composed of isolated communities with relatively frequent autosomal recessive (AR) conditions in each community. Clinical diagnosis of affected individuals has uncovered the pathogenic variants throughout the years. We investigated the diversity of pathogenic AR variants in a single village in northern Israel by exome analysis of 50 random, healthy adults descendants of the founders. Only likely pathogenic and pathogenic variants in known AR genes were selected. In this study 48 AR variants were found, of which 12 had been previously diagnosed in patients from this village, and for 11 with a frequency compatible with the frequency already known. Among the other 36 variants, 12 had been previously diagnosed in affected individuals in other Arab communities in Israel and 24 variants had not been previously characterized in this population. Of the 35 variants associated with conditions of moderate-severe medical consequences, only eight were known previously in this village. These findings emphasize the importance to better delineate the conditions at risk in a defined community, in particular for the development of preventive measures such as screening tests for reproductive couples, and for genetic counseling.

Homozygote loss-of-function variants in the human COCH gene underlie hearing loss.

Since 1999, the COCH gene encoding cochlin, has been linked to the autosomal dominant non-syndromic hearing loss, DFNA9, with or without vestibular abnormalities. The hearing impairment associated with the variants affecting gene function has been attributed to a dominant-negative effect. Mutant cochlin was seen to accumulate intracellularly, with the formation of aggregates both inside and outside the cells, in contrast to the wild-type cochlin that is normally secreted. While additional recessive variants in the COCH gene (DFNB110) have recently been reported, the mechanism of the loss-of-function (LOF) effect of the COCH gene product remains unknown. In this study, we used COS7 cell lines to investigate the consequences of a novel homozygous frameshift variant on RNA transcription, and on cochlin translation. Our results indicate a LOF effect of the variant and a major decrease in cochlin translation. This data have a dramatic impact on the accuracy of genetic counseling for both heterozygote and homozygote carriers of LOF variants in COCH.

Combined loss of LAP1B and LAP1C results in an early onset multisystemic nuclear envelopathy.

Nuclear envelopathies comprise a heterogeneous group of diseases caused by mutations in genes encoding nuclear envelope proteins. Mutations affecting lamina-associated polypeptide 1 (LAP1) result in two discrete phenotypes of muscular dystrophy and progressive dystonia with cerebellar atrophy. We report 7 patients presenting at birth with severe progressive neurological impairment, bilateral cataract, growth retardation and early lethality. All the patients are homozygous for a nonsense mutation in the TOR1AIP1 gene resulting in the loss of both protein isoforms LAP1B and LAP1C. Patient-derived fibroblasts exhibit changes in nuclear envelope morphology and large nuclear-spanning channels containing trapped cytoplasmic organelles. Decreased and inefficient cellular motility is also observed in these fibroblasts. Our study describes the complete absence of both major human LAP1 isoforms, underscoring their crucial role in early development and organogenesis. LAP1-associated defects may thus comprise a broad clinical spectrum depending on the availability of both isoforms in the nuclear envelope throughout life.

Genetics of hearing loss in the Arab population of Northern Israel.

For multiple generations, much of the Arab population of Northern Israel has lived in communities with consanguineous marriages and large families. These communities have been particularly cooperative and informative for understanding the genetics of recessive traits. We studied the genetics of hearing loss in this population, evaluating 168 families from 46 different villages. All families were screened for founder variants by Sanger sequencing and 13 families were further evaluated by sequencing all known genes for hearing loss using our targeted gene panel HEar-Seq. Deafness in 34 of 168 families (20%) was explained by founder variants in GJB2, SLC26A4, or OTOF. In 6 of 13 families (46%) evaluated using HEar-Seq, deafness was explained by damaging alleles of SLC26A4, MYO15A, OTOG, LOXHD1, and TBC1D24. In some genes critical to hearing, it is particularly difficult to interpret variants that might affect splicing, because the genes are not expressed in accessible tissue. To address this problem for possible splice-altering variants of MYO15A, we evaluated minigenes transfected into HEK293 cells. Results revealed exon skipping in the message of MYO15A c.9083+6T>A, and intron retention in the message of MYO15A c.8340G>A, in each case leading to a premature stop and consistent with co-segregation of homozygosity for each variant with hearing loss. The profile of genetics of hearing loss in this population reflects the genetic heterogeneity of hearing loss and the usefulness of synthetic technologies to evaluate potentially causal variants in genes not expressed in accessible tissues.

A homozygous TTN gene variant associated with lethal congenital contracture syndrome.

Pathogenic variants in the TTN gene have been reported to cause various cardiomyopathies and a range of skeletal muscle diseases, collectively known as titinopathies. We evaluated a consanguineous family multiple members affected with a lethal congenital contracture syndrome. Using exome sequencing, we identified a homozygous c.36122delC (p. P12041Lfs*20) variant in exon 167 in the fetal IC isoform of TTN. The finding expands the phenotypes that can be caused by pathogenic variants TTN, which should be considered in lethal congenital contracture syndromes, arthrogryposis multiplex congenita, congenital myopathies, and hydrops fetalis.

Exploring the genetic basis of 3MC syndrome: Findings in 12 further families.

The 3MC syndromes are a group of rare autosomal recessive disorders where the main clinical features are cleft lip and palate, hypertelorism, highly arched eyebrows, caudal appendage, postnatal growth deficiency, and genitourinary tract anomalies. Ophthalmological abnormalities, most notably anterior chamber defects may also be seen. We describe the clinical and molecular findings in 13 individuals with suspected 3MC syndrome from 12 previously unreported families. The exclusion of the MASP1 and COLEC11 Loci in two individuals from different consanguineous families and the absence of mutations in four further individuals sequenced for both genes raises the possibility that that there is further genetic heterogeneity of 3MC syndrome.

Diagnostic challenges of Wilson's disease presenting as acute pancreatitis, cholangitis, and jaundice.

Wilson's disease is a rare disorder of copper transport in hepatic cells, and may present as cholestatic liver disease; pancreatitis and cholangitis are rarely associated with Wilsons's disease. Moreover, cases of Wilson's disease presenting as pigmented gallstone pancreatitis have not been reported in the literature. In the present report, we describe a case of a 37-year-old man who was admitted with jaundice and abdominal pain. The patient was diagnosed with acute pancreatitis, cholangitis, and obstructive jaundice caused by pigmented gallstones that were detected during retrograde cholangiopancreatography. However, because of his long-term jaundice and the presence of pigmented gallstones, the patient underwent further evaluation for Wilson's disease, which was subsequently confirmed. This patient's unique presentation exemplifies the overlap in the clinical and laboratory parameters of Wilson's disease and cholestasis, and the difficulties associated with their differentiation. It suggests that Wilson's disease should be considered in patients with pancreatitis, cholangitis, and severe protracted jaundice caused by pigmented gallstones.

A novel splice site mutation of CDHR1 in a consanguineous Israeli Christian Arab family segregating autosomal recessive cone-rod dystrophy.

PURPOSE: To investigate the genetic basis for autosomal recessive cone-rod dystrophy in a consanguineous Israeli Christian Arab family. METHODS: Patients underwent a detailed ophthalmic examination, including funduscopy, electroretinography (ERG), visual field testing, and optical coherence tomography. Genome-wide homozygosity mapping using a single nucleotide polymorphism array was performed to identify homozygous regions shared between the two affected individuals. Mutation screening of the underlying gene was performed with direct sequencing. In silico analysis was used to predict the effect of the mutation on splicing. RESULTS: The family included two affected individuals. Clinical findings included progressive deterioration of visual acuity, photophobia, defective color vision, loss of central visual fields, pigmentary deposits localized mainly in the peripheral retina, a thinned and atrophic macular region, retinal vessel attenuation, absent ERG cone responses, and reduced ERG rod responses. Homozygosity mapping revealed several homozygous intervals shared among the affected individuals. One, a 12Mb interval on chromosome 10, included the CDHR1 gene. Direct sequencing revealed a single base transversion, c.1485+2T>G, located in the conserved donor splice site of Intron 13. This mutation cosegregated with the disease in the family, and was not detected in 208 Israeli Christian Arab control chromosomes. In silico analysis predicted that this mutation eliminates the Intron 13 donor splice site. CONCLUSIONS: Only three distinct pathogenic mutations of CDHR1 have been reported to date in patients with autosomal recessive retinal degeneration. Here we report a novel splice site mutation of CDHR1, c.1485+2T>G, underlying autosomal recessive cone-rod dystrophy in a consanguineous Israeli Christian Arab family. This report expands the spectrum of pathogenic mutations of the CDHR1 gene.

Further delineation of the phenotype of severe congenital neutropenia type 4 due to mutations in G6PC3.

Severe congenital neutropenia type 4 (SCN4) is an autosomal recessive condition, which was defined recently with identification of the causative mutations in G6PC3. To date there are only three reports in the literature describing patients with SCN4 with mutations in the G6PC3 gene. We report four individuals with SCN4 who belong to a single large consanguineous kindred. We provide an overview of the non-haematological features of the condition with a focus on the adult phenotype, which has not been previously described in detail. We show that the superficial venous changes seen in SCN4 patients can develop into varicose veins and venous ulcers in adulthood. We review the range of congenital anomalies associated with SCN4. We demonstrate that secundum atrial septal defect, patent ductus arteriosus and valvular defects are the most frequent cardiac anomalies in SCN4. Drawing parallels with type 1 glycogen storage disease, we propose that poor growth of prenatal onset, mild-to-moderate learning disability, primary pulmonary hypertension, delayed or incomplete puberty, hypothyroidism and dysmorphism likely represent features of this syndrome. We also suggest monitoring for lipid anomalies, and kidney and liver function in affected patients. Delineation of the SCN4 phenotype may help in appropriate treatment and management and provide further insights into the pathogenesis of this multisystem disease.

Novel mutations of MYO7A and USH1G in Israeli Arab families with Usher syndrome type 1.

PURPOSE: This study investigated the genetic basis for Usher syndrome type 1 (USH1) in four consanguineous Israeli Arab families. METHODS: Haplotype analysis for all known USH1 loci was performed in each family. In families for which haplotype analysis was inconclusive, we performed genome-wide homozygosity mapping using a single nucleotide polymorphism (SNP) array. For mutation analysis, specific primers were used to PCR amplify the coding exons of the MYO7A, USH1C, and USH1G genes including intron-exon boundaries. Mutation screening was performed with direct sequencing. RESULTS: A combination of haplotype analysis and genome-wide homozygosity mapping indicated linkage to the USH1B locus in two families, USH1C in one family and USH1G in another family. Sequence analysis of the relevant genes (MYO7A, USH1C, and USH1G) led to the identification of pathogenic mutations in all families. Two of the identified mutations are novel (c.1135-1147dup in MYO7A and c.206-207insC in USH1G). CONCLUSIONS: USH1 is a genetically heterogenous condition. Of the five USH1 genes identified to date, USH1C and USH1G are the rarest contributors to USH1 etiology worldwide. It is therefore interesting that two of the four Israeli Arab families reported here have mutations in these two genes. This finding further demonstrates the unique genetic structure of the Israeli population in general, and the Israeli Arab population in particular, which due to high rates of consanguinity segregates many rare autosomal recessive genetic conditions.