Health Survey of Adults with Neurofibromatosis 1 Compared to Population Study Controls.

Neurofibromatosis type 1 (NF1) is a genetic, autosomal dominant multi-organ disease characterized by susceptibility to tumor formation, changes in skin pigmentation, skeletal abnormalities, and neuropsychological deficits. Clinical studies have shown impaired health-related quality of life (HQoL) in adults with NF1. However, little is known about HQoL in non-clinical NF1 samples. We conducted a cross-sectional self-report survey of 142 persons with NF1 (M age = 50.3 years, SD = 12.0, range 32 to 80; 62.0% females) recruited from non-clinical settings. Several HQoL domains, including life satisfaction, mental health, sleep, pain, gastrointestinal problems, oral health, and social support, were compared between the NF1 sample and 46,293 controls from the HUNT3 population study. We also examined gender differences within the NF1 sample and predictors of HQoL. Compared to controls, the NF1 sample reported significantly poorer life satisfaction, mental health, sleep, and oral health, and more pain, gastrointestinal problems, comorbid diseases, and memory problems. Several HQoL domains were significantly correlated. Mental health was the only unique significant predictor of overall life satisfaction. Women with NF1 reported significantly more mental health, sleep, and pain problems than men with NF1. Mental health assessment and management should be integrated into clinical care of persons with NF1 to potentially improve their HQoL.

Biallelic variants in KIF14 cause intellectual disability with microcephaly.

Kinesin proteins are critical for various cellular functions such as intracellular transport and cell division, and many members of the family have been linked to monogenic disorders and cancer. We report eight individuals with intellectual disability and microcephaly from four unrelated families with parental consanguinity. In the affected individuals of each family, homozygosity for likely pathogenic variants in KIF14 were detected; two loss-of-function (p.Asn83Ilefs*3 and p.Ser1478fs), and two missense substitutions (p.Ser841Phe and p.Gly459Arg). KIF14 is a mitotic motor protein that is required for spindle localization of the mitotic citron rho-interacting kinase, CIT, also mutated in microcephaly. Our results demonstrate the involvement of KIF14 in development and reveal a wide phenotypic variability ranging from fetal lethality to moderate developmental delay and microcephaly.

Familial globotriaosylceramide-associated cardiomyopathy mimicking Fabry disease.

OBJECTIVE: To characterise a globotriaosylceramide (Gb3) storage cardiomyopathy mimicking Fabry. METHODS: We investigated five patients from two unrelated families with early adult onset unexplained left ventricular hypertrophy. Endomyocardial biopsy was performed in all patients and diagnostic kidney biopsies in two of them. We measured α-galactosidase A activity in all patients. Three patients were checked for LAMP1 or LAMP2 deficiency and screened for congenital disorders of glycosylation. Gb3 concentration was quantified in plasma, urinary sediment and cardiac muscle. We sequenced the Fabry and Danon genes and looked for other genetic causes by single-nucleotide polymorphism array haplotyping and whole exome sequencing. RESULTS: Three patients had a striking fat distribution around the buttocks and upper thighs. All patients developed bradyarrhythmias and needed pacemakers. Cardiac transplantation was performed in three patients due to end-stage heart failure, one patient died before transplantation. The cardiomyocytes contained lysosomal vacuoles with lamellar myelin-like deposits. Interstitial cells had vacuoles containing granular material. Deposits were found in the kidneys without renal dysfunction. The histological pattern was atypical for Fabry disease. Biochemical studies revealed normal activity of α-galactosidase A and other relevant enzymes. There was a selective accumulation of Gb3 in cardiomyocytes, at levels found in patients with Fabry disease, but no mutations in the Fabry gene, and Fabry disease was excluded. Other known lysosomal storage diseases were also excluded. Single-nucleotide polymorphism array haplotyping and whole exome sequencing could not identify the genetic cause. CONCLUSIONS: We describe a novel familial Gb3-associated cardiomyopathy. Autosomal recessive inheritance is likely, but the genetic and metabolic cause remains to be identified.

Occipital horn syndrome and classical Menkes Syndrome caused by deep intronic mutations, leading to the activation of ATP7A pseudo-exon.

Menkes disease is an X-linked disorder of copper metabolism caused by mutations in the ATP7A gene. Whereas most of the patients exhibit a severe classical form, about 9% of the patients exhibit a milder form of Menkes disease. The mildest form is called occipital horn syndrome (OHS). Mutations in the ATP7A gene can be identified in 95-98% of the Menkes disease patients by standard screening techniques. Investigation of RNA isolated from the fibroblasts of eleven patients with no identified mutations was performed, and revealed inclusion of new pseudo-exons into the ATP7A mRNA from three unrelated patients: two patients with OHS and one patient with classical Menkes disease. The pseudo-exons were inserted between exons 10 and 11, between exons 16 and 17 and between exons 14 and 15 in the three patients, as a result of deep intronic mutations. This is the first time the activation of pseudo-exons is demonstrated in the ATP7A gene, and it demonstrates the usefulness of RNA analysis, in terms of revealing disease-causing mutations in noncoding regions. The fact that three different mutations cause disease by the activation of pseudo-exon inclusion also indicates that in Menkes disease this is an important mechanism, which has hitherto been overlooked.

Mutations in ADAR1 cause Aicardi-Goutières syndrome associated with a type I interferon signature.

Adenosine deaminases acting on RNA (ADARs) catalyze the hydrolytic deamination of adenosine to inosine in double-stranded RNA (dsRNA) and thereby potentially alter the information content and structure of cellular RNAs. Notably, although the overwhelming majority of such editing events occur in transcripts derived from Alu repeat elements, the biological function of non-coding RNA editing remains uncertain. Here, we show that mutations in ADAR1 (also known as ADAR) cause the autoimmune disorder Aicardi-Goutières syndrome (AGS). As in Adar1-null mice, the human disease state is associated with upregulation of interferon-stimulated genes, indicating a possible role for ADAR1 as a suppressor of type I interferon signaling. Considering recent insights derived from the study of other AGS-related proteins, we speculate that ADAR1 may limit the cytoplasmic accumulation of the dsRNA generated from genomic repetitive elements.

Vestibular schwannomas occur in schwannomatosis and should not be considered an exclusion criterion for clinical diagnosis.

Schwannomatosis is a recently delineated inherited condition that has clinical overlap with neurofibromatosis type 2 (NF2). Diagnostic criteria have been developed to distinguish schwannomatosis from NF2, but the existence of mosaic NF2, which may closely mimic schwannomatosis, makes even these criteria problematic. In particular, it is not clear why there is a relative sparing of the cranial nerves from schwannomas in schwannomatosis. We have identified two individuals with schwannomatosis and a unilateral vestibular schwannoma (VS), where a diagnosis of NF2 has been excluded. A third case with an identified SMARCB1 mutation was reported by two radiologists to have a VS, but this was later confirmed as a jugular schwannoma. These cases question whether the current exclusion of a VS from the clinical diagnosis of schwannomatosis is justified.

[Neurofibromatosis type 2 and auditory brainstem implantation]. / Nevrofibromatose type 2 og auditorisk hjernestammeimplantat.

BACKGROUND: Neurofibromatosis type 2 (NF2) is a rare and severe autosomal dominant disorder caused by mutations in a tumour suppressor gene. This article reviews NF2 and its treatment with auditory brainstem implantation. MATERIAL AND METHODS: The review is based on the authors' experience with the disease and literature identified through a non-systematic search of PubMed. RESULTS: NF2 is caused by loss-of-normal function of the tumour suppressor protein merlin. Merlin normally suppresses cell growth and proliferation. The clinical picture is dominated by neurological symptoms, caused by multiple tumours - mainly schwannomas and meningeomas. The hallmark of the disease is development of bilateral vestibular schwannomas, and the most common presenting symptom in adults is progressive hearing loss. Presenile cataract, ocular motility disorders, peripheral neuropathy and skin tumours are other common findings. The majority of patients become deaf, many patients become severely disabled and life expectancy is reduced. The goal of management is conservation of function and maintenance of quality of life. Auditory brainstem implants stimulate the cochlear nucleus directly and provide substantial auditory benefits to patients with NF2. INTERPRETATION: A multidisciplinary approach in specialty centres is recommended. Management by an experienced team reduces mortality and improves outcome after surgery. Auditory brainstem implantation is an important part of the hearing rehabilitation in these patients. Emerging knowledge of the molecular disease mechanisms offers hope for new therapeutic strategies.

Investigations as a prerequisite for genetic counseling after termination of pregnancy based on sonographic detection of serious central nervous system--or skeletal anomalies.

OBJECTIVES: The primary aim was to evaluate which investigation performed after sonographic detection of central nervous system (CNS) or skeletal anomalies that had highest diagnostic yield. The secondary aim was to estimate recurrence risk. Design. Retrospective review of patients' records. SETTING: Tertiary fetal medicine referral center. SAMPLE: Pregnancy terminations (n=97) because of CNS or skeletal anomalies during a 17-year period, within 12-24 weeks gestation. METHODS: Two medical geneticists and one genetic counselor reviewed charts independently. MAIN OUTCOME MEASURES: Primary ultrasound diagnosis, change in diagnosis following supplementary examinations in addition to prenatal ultrasound (medical history, autopsy, post-mortem X-ray, karyotyping, targeted DNA analysis and investigations for infection), the most useful method to determine diagnosis, and recurrence risk estimate including inter-rater agreement. RESULTS: Mean gestational age was 19.8 weeks. All three investigators agreed in each case on which investigation constituted the best basis to determine the most precise diagnosis. The examinations performed in addition to prenatal ultrasound provided important diagnostic information in 54 cases (56%) and altered recurrence risk in 22 (23%) cases; in eight of these cases the risk estimate was increased. In nine cases (9%) the investigators disagreed in their estimates of recurrence risk. Kappa for inter-rater agreement was >0.90. CONCLUSIONS: A panel of diagnostic investigations, depending on the organ system involved, allows for a more precise diagnosis and a more reliable estimate of recurrence risk than prenatal ultrasound alone. In some instances, recurrence risk estimation is not straightforward as evidenced by lack of consensus.

Clinical and molecular phenotype of Aicardi-Goutieres syndrome.

Aicardi-Goutieres syndrome (AGS) is a genetic encephalopathy whose clinical features mimic those of acquired in utero viral infection. AGS exhibits locus heterogeneity, with mutations identified in genes encoding the 3'-->5' exonuclease TREX1 and the three subunits of the RNASEH2 endonuclease complex. To define the molecular spectrum of AGS, we performed mutation screening in patients, from 127 pedigrees, with a clinical diagnosis of the disease. Biallelic mutations in TREX1, RNASEH2A, RNASEH2B, and RNASEH2C were observed in 31, 3, 47, and 18 families, respectively. In five families, we identified an RNASEH2A or RNASEH2B mutation on one allele only. In one child, the disease occurred because of a de novo heterozygous TREX1 mutation. In 22 families, no mutations were found. Null mutations were common in TREX1, although a specific missense mutation was observed frequently in patients from northern Europe. Almost all mutations in RNASEH2A, RNASEH2B, and RNASEH2C were missense. We identified an RNASEH2C founder mutation in 13 Pakistani families. We also collected clinical data from 123 mutation-positive patients. Two clinical presentations could be delineated: an early-onset neonatal form, highly reminiscent of congenital infection seen particularly with TREX1 mutations, and a later-onset presentation, sometimes occurring after several months of normal development and occasionally associated with remarkably preserved neurological function, most frequently due to RNASEH2B mutations. Mortality was correlated with genotype; 34.3% of patients with TREX1, RNASEH2A, and RNASEH2C mutations versus 8.0% RNASEH2B mutation-positive patients were known to have died (P=.001). Our analysis defines the phenotypic spectrum of AGS and suggests a coherent mutation-screening strategy in this heterogeneous disorder. Additionally, our data indicate that at least one further AGS-causing gene remains to be identified.

[Complex craniofacial synostoses]. / Komplekse kraniofaciale synostoser.

BACKGROUND: Complex craniofacial synostosis is a group of rare genetic disorders characterized by premature closure of the sutures in the craniofacial skeleton and which to varying degrees affects the extremities. MATERIAL AND METHODS: On the basis of relevant literature, we present a review of syndromal craniofacial synostosis. RESULTS: Phenotypically, the complex craniofacial syndromes have many similarities. Synostosis of the sutures of the cranial vault can result in a variety of skull deformations, depending on the sutures involved, the sequence of premature closure, and the time of closure. Synostosis of the sutures in the skull base and facial skeleton leads to shallow orbits, exophthalmus, hypertelorism, midface retrusion, and prognathia. INTERPRETATION: Precise diagnosis of complex craniofacial syndromes may be difficult solely on the basis of a clinical examination. However, several of the most common syndromes are caused by mutations in genes that code for fibroblast growth-factor receptors. Children with a suspected complex craniofacial syndrome should be referred to genetic testing.

Dental characteristics in Williams syndrome: a clinical and radiographic evaluation.

Williams syndrome is a rare congenital syndrome with distinctive craniofacial features, cardiovascular abnormalities, and behavior characteristics including mental retardation. The dental abnormalities have received scant attention in previous literature. The aim of this study was to describe dental characteristics in individuals with Williams syndrome. In a group of 41 individuals more than 10 years of age, 40.5% had agenesis of one or more permanent teeth and 11.9% had agenesis of 6 permanent teeth or more. The mesio-distal and labio-lingual dimensions of permanent tooth crowns were measured on 31 dental study casts from individuals older than 12 years. The mesio-distal and labio-lingual dimensions were significantly smaller compared with a reference sample. An analysis of tooth morphology was performed on the same dental study casts revealing altered tooth morphology. A high proportion of maxillary and mandibular incisors was tapered or screwdriver shaped. An evaluation of taurodontism on mandibular permanent molars was performed using a metric crown-body/root ratio. However, most of the molars rated as being taurodontic had short or extremely short total tooth lengths and could thus be rated taurodontic without meeting the classical definition. The results of this study indicate that although there is variation in dental development in individuals with Williams syndrome, agenesis of permanent teeth in combination with aberrations in tooth size and morphology may affect dental esthetics and complicate orthodontic and prosthodontic treatment.