Repeat length variations in ATXN1 and AR modify disease expression in Alzheimer's disease.

Genomewide association studies (GWASs) have contributed greatly to unraveling the genetic basis of Alzheimer's disease (AD). However, a large amount of "missing heritability" remains. In this exploratory study, we investigated the effect of cytosine-adenine-guanine (CAG) repeats in polyglutamine disease-associated genes (PDAGs) on the risk of AD and its expression.

Two novel cases expanding the phenotype of SETD2-related overgrowth syndrome.

The SETD2-related overgrowth syndrome is also called "Luscan-Lumish syndrome" (OMIM 616831) with the clinical characteristics of intellectual disability, speech delay, macrocephaly, facial dysmorphism, and autism spectrum disorders. We report on two novel patients a 4.5-year-old boy and a 23-year-old female adolescent with a speech and language developmental delay, autism spectrum disorder and macrocephaly, who were both diagnosed with SETD2-related overgrowth syndrome due to de novo frameshift mutations in the SETD2 gene.

Benign and malignant tumors in Rubinstein-Taybi syndrome.

Rubinstein-Taybi syndrome (RSTS) is a multiple congenital anomalies syndrome associated with mutations in CREBBP (70%) and EP300 (5-10%). Previous reports have suggested an increased incidence of specific benign and possibly also malignant tumors. We identified all known individuals diagnosed with RSTS in the Netherlands until 2015 (n = 87) and studied the incidence and character of neoplastic tumors in relation to their CREBBP/EP300 alterations.

High Yield of Pathogenic Germline Mutations Causative or Likely Causative of the Cancer Phenotype in Selected Children with Cancer.

In many children with cancer and characteristics suggestive of a genetic predisposition syndrome, the genetic cause is still unknown. We studied the yield of pathogenic mutations by applying whole-exome sequencing on a selected cohort of children with cancer. To identify mutations in known and novel cancer-predisposing genes, we performed trio-based whole-exome sequencing on germline DNA of 40 selected children and their parents.

Huntingtin gene repeat size variations affect risk of lifetime depression.

Huntington disease (HD) is a severe neuropsychiatric disorder caused by a cytosine-adenine-guanine (CAG) repeat expansion in the HTT gene. Although HD is frequently complicated by depression, it is still unknown to what extent common HTT CAG repeat size variations in the normal range could affect depression risk in the general population. Using binary logistic regression, we assessed the association between HTT CAG repeat size and depression risk in two well-characterized Dutch cohorts─the Netherlands Study of Depression and Anxiety and the Netherlands Study of Depression in Older Persons─including 2165 depressed and 1058 non-depressed persons.

Predictive testing of minors for Huntington's disease: The UK and Netherlands experiences.

A consistent feature of predictive testing guidelines for Huntington's disease (HD) is the recommendation not to undertake predictive tests on those < 18 years. Exceptions are made but the extent of, and reasons for, deviation from the guidelines are unknown. The UK Huntington's Prediction Consortium has collected data annually on predictive tests undertaken from the 23 UK genetic centers.

Archetypal mutations frequent in public exome: implications for CADASIL.

Objective: To determine the frequency of distinctive EGFr cysteine altering mutations in the 60,706 exomes of the exome aggregation consortium (ExAC) database.

Methods: ExAC was queried for mutations distinctive for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), namely mutations leading to a cysteine amino acid change in one of the 34 EGFr domains of NOTCH3. The genotype-phenotype correlation predicted by the ExAC data was tested in an independent cohort of Dutch CADASIL patients using quantified MRI lesions.

CREBBP mutations in individuals without Rubinstein-Taybi syndrome phenotype.

Mutations in CREBBP cause Rubinstein-Taybi syndrome. By using exome sequencing, and by using Sanger in one patient, CREBBP mutations were detected in 11 patients who did not, or only in a very limited manner, resemble Rubinstein-Taybi syndrome. The combined facial signs typical for Rubinstein-Taybi syndrome were absent, none had broad thumbs, and three had only somewhat broad halluces.

Mosaic CREBBP mutation causes overlapping clinical features of Rubinstein-Taybi and Filippi syndromes.

Rubinstein-Taybi syndrome (RTS, OMIM 180849) and Filippi syndrome (FLPIS, OMIM 272440) are both rare syndromes, with multiple congenital anomalies and intellectual deficit (MCA/ID). We present a patient with intellectual deficit, short stature, bilateral syndactyly of hands and feet, broad thumbs, ocular abnormalities, and dysmorphic facial features. These clinical features suggest both RTS and FLPIS.

Is There Convincing Evidence that Intermediate Repeats in the HTT Gene Cause Huntington's Disease?

Background And Objective: Huntington's disease (HD) is a neurodegenerative disease associated with a CAG repeat expansion in the Huntingtin (HTT) gene. A trinucleotide size between 27 and 35 is considered 'intermediate' and not to cause symptoms and signs of HD. There are articles claiming otherwise, however publishing only the cases that have a HD phenotype introduces a significant publication bias.

Making (anti-) sense out of huntingtin levels in Huntington disease.

Background: Huntington disease (HD) is an autosomal dominant neurodegenerative disorder, characterized by motor, psychiatric and cognitive symptoms. HD is caused by a CAG repeat expansion in the first exon of the HTT gene, resulting in an expanded polyglutamine tract at the N-terminus of the huntingtin protein. Typical disease onset is around mid-life (adult-onset HD) whereas onset below 21 years is classified as juvenile HD.

Noninvasive prenatal diagnosis of Huntington disease: detection of the paternally inherited expanded CAG repeat in maternal plasma.

Objective: With a shift towards noninvasive testing, we have explored and validated the use of noninvasive prenatal diagnosis (NIPD) for Huntington disease (HD).

Methods: Fifteen couples have been included, assessing a total of n = 20 pregnancies. Fetal paternally inherited CAG repeat length was determined in total cell-free DNA from maternal plasma using a direct approach by PCR and subsequent fragment analysis.

A new mutation for Huntington disease following maternal transmission of an intermediate allele.

New mutations for Huntington disease (HD) originate from CAG repeat expansion of intermediate alleles (27-35 CAG). Expansions of such alleles into the pathological range (≥ 36 CAG) have been exclusively observed in paternal transmission. We report the occurrence of a new mutation that defies the paternal expansion bias normally observed in HD.

Coffin-Siris syndrome and the BAF complex: genotype-phenotype study in 63 patients.

De novo germline variants in several components of the SWI/SNF-like BAF complex can cause Coffin-Siris syndrome (CSS), Nicolaides-Baraitser syndrome (NCBRS), and nonsyndromic intellectual disability. We screened 63 patients with a clinical diagnosis of CSS for these genes (ARID1A, ARID1B, SMARCA2, SMARCA4, SMARCB1, and SMARCE1) and identified pathogenic variants in 45 (71%) patients. We found a high proportion of variants in ARID1B (68%).

EMQN/CMGS best practice guidelines for the molecular genetic testing of Huntington disease.

Huntington disease (HD) is caused by the expansion of an unstable polymorphic trinucleotide (CAG)n repeat in exon 1 of the HTT gene, which translates into an extended polyglutamine tract in the protein. Laboratory diagnosis of HD involves estimation of the number of CAG repeats. Molecular genetic testing for HD is offered in a wide range of laboratories both within and outside the European community.

Parent-of-origin differences of mutant HTT CAG repeat instability in Huntington's disease.

Background: Huntington's disease (HD) is a progressive autosomal dominant neurodegenerative disorder caused by a CAG repeat expansion in the HD gene (HTT). The CAG domain of mutant HTT is unstable upon intergenerational transmission, however, little is known about the underlying mechanisms.

Methods: From the HD archives of the Leiden University Medical Centre DNA samples from all parent-offspring pairs involving 36 CAG repeats or more were selected.

Myosin IXB variant increases the risk of celiac disease and points toward a primary intestinal barrier defect.

Celiac disease is probably the best-understood immune-related disorder. The disease presents in the small intestine and results from the interplay between multiple genes and gluten, the triggering environmental factor. Although HLA class II genes explain 40% of the heritable risk, non-HLA genes accounting for most of the familial clustering have not yet been identified.

The interferon gamma gene in celiac disease: augmented expression correlates with tissue damage but no evidence for genetic susceptibility.

Celiac disease (CD) is a complex genetic disorder characterized by gluten intolerance. The Th1 immune response, with a key position for interferon gamma (IFN-gamma), is an important determinant of intestinal remodeling in CD. We aimed at further ascertaining the role of IFN-gamma, either as a genetic factor in the etiology, or as a facilitator of disease initiation/progression.

CTLA4 +49 A/G and CT60 polymorphisms in Dutch coeliac disease patients.

Coeliac disease is an autoimmune disorder, characterised by villous atrophy of the small intestine, which results from a T-cell-mediated response to gluten-derived peptides. The cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is involved in the regulation of T-cell activation and the CTLA4 +49 A/G polymorphism in exon 1 has been implicated in several autoimmune disorders, including coeliac disease. However, this polymorphism was recently excluded as being the causal variant in Graves' disease, autoimmune hypothyroidism and type I diabetes mellitus.

A genomewide screen in a four-generation Dutch family with celiac disease: evidence for linkage to chromosomes 6 and 9.

Objectives: Celiac disease is caused by the interaction of multiple genes and environmental factors. Inheritance of the disease shows a complex pattern with a 10% sibling recurrence risk. The HLA-region is a major genetic risk locus in celiac disease, but genes outside this region are expected to contribute to the disease risk as well.

A major non-HLA locus in celiac disease maps to chromosome 19.

Background And Aims: The pathogenesis of celiac disease is still unknown despite its well-known association with human leukocyte antigen (HLA)-DQ2 and DQ8. It is clear that non-HLA genes contribute to celiac disease development as well, but none of the previous genome-wide screens in celiac disease have resulted in identification of these genes.

Methods: We, therefore, performed a 2-stage, genome-wide screen in 101 affected sibpairs from 82 Dutch families who met strict diagnostic criteria.