Diagnosis and Treatment Before Assisted Reproductive Treatments. Guideline of the DGGG, OEGGG and SGGG (S2k Level, AWMF Register Number 015-085, February 2019) - Part 2, Hemostaseology, Andrology, Genetics and History of Malignant Disease

Introduction Supporting and counselling couples with fertility issues prior to starting ART is a multidisciplinary diagnostic and therapeutic challenge. The first German-language interdisciplinary S2k guideline on "Diagnosis and Therapy Before Assisted Reproductive Treatments (ART)" was published in February 2019. The guideline was developed in the context of the guidelines program of the German Society of Gynecology and Obstetrics (DGGG) in cooperation with the Swiss Society of Gynecology and Obstetrics (SGGG) and the Austrian Society of Gynecology and Obstetrics (OEGGG). Aim In one third of cases, the cause of involuntary childlessness remains unclear, even if the woman or man have numerous possible risk factors. Because the topic is still very much taboo, couples may be socially isolated and often only present quite late to a fertility center. There is no standard treatment concept for these patients at present, as there are currently no standard multidisciplinary procedures for the diagnostic workup and treatment of infertility. The aim of this guideline is to provide physicians with evidence-based recommendations for counselling, diagnosis and treatment. Methods This S2k guideline was developed on behalf of the Guidelines Commission of the DGGG by representative members from different professional medical organizations and societies using a structured consensus process. Recommendations This second part of the guideline describes the hematological workup for women as well as additional diagnostic procedures which can be used to investigate couples and which are carried out in cooperation with physicians working in other medical fields such as andrologists, geneticists and oncologists.

Early onset facioscapulohumeral muscular dystrophy - Long-term follow-up of a patient with total facial diplegia

We report a patient with early onset facioscapulohumeral muscular dystrophy type 1 (FSHD1) who was not diagnosed until 48 years of age. She developed progressive facial diplegia from the age of 4-5 years followed by limb muscle weakness. Motor nerve conduction was normal, myopathic changes were seen electromyographically. Creatine kinase activity was mildly increased at the beginning. Muscle biopsy at 8 years suggested a neurogenic pattern, a second biopsy at age 30 was chronic myopathic with fibre calibre variation. The patient lost the ability to walk at age 44. When last seen she had total facial diplegia, no active movements in her limbs, mild kyphoscoliosis and a rigid thoracic spine. Molecular studies revealed a shortened D4Z4 fragment confirming the diagnosis FSHD1. Her family history was unremarkable, suggesting a de novo mutation. This report is to illustrate the evolving phenotype of early onset FSHD1 with predominating facial palsy.

Pregnancy and Delivery in Women With Congenital Myopathies

Reports on pregnancy and delivery issues in women with congenital myopathies are scarce. In this review, we summarize the medical literature along with updates of our own data. Included are patients with nemaline myopathy (n = 11), central core disease (n = 6), multi-minicore disease (n = 2), cytoplasmic body myopathy (n = 1), and congenital fiber-type disproportion (n = 1). Apart from 1 patient with nemaline myopathy, who had used a wheelchair from the age of 18years, all other women were able to walk when becoming pregnant. In comparison with the general population, there were no increased pregnancy or delivery complications, apart from the fact that 38% elective Cesarean sections took place. Neonatal outcome was favorable. In cases where a possible influence of gestation on muscle function was assessed, a deterioration during or after pregnancy was not observed. Patients who wish to have children should be advised by a multidisciplinary team according to the specific diagnosis, severity, and distribution of muscle weakness.

Loss of tubulin deglutamylase CCP1 causes infantile-onset neurodegeneration

A set of glutamylases and deglutamylases controls levels of tubulin polyglutamylation, a prominent post-translational modification of neuronal microtubules. Defective tubulin polyglutamylation was first linked to neurodegeneration in the Purkinje cell degeneration (pcd) mouse, which lacks deglutamylase CCP1, displays massive cerebellar atrophy, and accumulates abnormally glutamylated tubulin in degenerating neurons. We found biallelic rare and damaging variants in the gene encoding CCP1 in 13 individuals with infantile-onset neurodegeneration and confirmed the absence of functional CCP1 along with dysregulated tubulin polyglutamylation. The human disease mainly affected the cerebellum, spinal motor neurons, and peripheral nerves. We also demonstrate previously unrecognized peripheral nerve and spinal motor neuron degeneration in pcd mice, which thus recapitulated key features of the human disease. Our findings link human neurodegeneration to tubulin polyglutamylation, entailing this post-translational modification as a potential target for drug development for neurodegenerative disorders.

Evidence of mild founder LMOD3 mutations causing nemaline myopathy 10 in Germany and Austria

OBJECTIVE

To expand the clinical and genetic spectrum of nemaline myopathy 10 by a series of Austrian and German patients with a milder disease course and missense mutations in LMOD3.

METHODS

We characterized the clinical features and the genetic status of 4 unrelated adolescent or adult patients with nemaline myopathy.

RESULTS

The 4 patients showed a relatively mild disease course. They all have survived into adulthood, 3 of 4 have remained ambulatory, and all showed marked facial weakness. Muscle biopsy specimens gave evidence of nemaline bodies. All patients were unrelated but originated from Austria (Tyrol and Upper Austria) and Southern Germany (Bavaria). All patients carried the missense variant c.1648C>T, p.(Leu550Phe) in the LMOD3 gene, either on both alleles or in trans with another missense variant (c.1004A>G, p.Gln335Arg). Both variants were not reported previously.

CONCLUSIONS

In 2014, a severe form of congenital nemaline myopathy caused by disrupting mutations in LMOD3 was identified and denoted as NEM10. Unlike the previously reported patients, who had a severe clinical picture with a substantial risk of early death, our patients showed a relatively mild disease course. As the missense variant c.1648C>T is located further downstream compared to all previously published LMOD3 mutations, it might be associated with higher protein expression compared to the reported loss-of-function mutations. The apparent clusters of 2 mild mutations in Germany and Austria in 4 unrelated families may be explained by a founder effect.

Recurrent Miscarriage: Diagnostic and Therapeutic Procedures. Guideline of the DGGG, OEGGG and SGGG (S2k-Level, AWMF Registry Number 015/050)

Purpose

Official guideline of the German Society of Gynecology and Obstetrics (DGGG), the Austrian Society of Gynecology and Obstetrics (ÖGGG) and the Swiss Society of Gynecology and Obstetrics (SGGG). The aim of this guideline was to standardize the diagnosis and treatment of couples with recurrent miscarriage (RM). Recommendations were based on the current literature and the views of the involved committee members.

Methods

Based on the current literature, the committee members developed the statements and recommendations of this guideline in a formalized process which included DELPHI rounds and a formal consensus meeting.

Recommendations

Recommendations for the diagnosis and treatment of patients with RM were compiled based on the international literature. Specific established risk factors such as chromosomal, anatomical, endocrine, hemostatic, psychological, infectious and immunological disorders were taken into consideration.

Loss of function of SLC25A46 causes lethal congenital pontocerebellar hypoplasia

Disturbed mitochondrial fusion and fission have been linked to various neurodegenerative disorders. In siblings from two unrelated families who died soon after birth with a profound neurodevelopmental disorder characterized by pontocerebellar hypoplasia and apnoea, we discovered a missense mutation and an exonic deletion in the SLC25A46 gene encoding a mitochondrial protein recently implicated in optic atrophy spectrum disorder. We performed functional studies that confirmed the mitochondrial localization and pro-fission properties of SLC25A46. Knockdown of slc24a46 expression in zebrafish embryos caused brain malformation, spinal motor neuron loss, and poor motility. At the cellular level, we observed abnormally elongated mitochondria, which was rescued by co-injection of the wild-type but not the mutant slc25a46 mRNA. Conversely, overexpression of the wild-type protein led to mitochondrial fragmentation and disruption of the mitochondrial network. In contrast to mutations causing non-lethal optic atrophy, missense mutations causing lethal congenital pontocerebellar hypoplasia markedly destabilize the protein. Indeed, the clinical severity appears inversely correlated with the relative stability of the mutant protein. This genotype-phenotype correlation underscores the importance of SLC25A46 and fine tuning of mitochondrial fission and fusion in pontocerebellar hypoplasia and central neurodevelopment in addition to optic and peripheral neuropathy across the life span.

Extension of the phenotype of biallelic loss-of-function mutations in SLC25A46 to the severe form of pontocerebellar hypoplasia type I

Biallelic mutations in SLC25A46, encoding a modified solute transporter involved in mitochondrial dynamics, have been identified in a wide range of conditions such as hereditary motor and sensory neuropathy with optic atrophy type VIB (OMIM: *610826) and congenital lethal pontocerebellar hypoplasia (PCH). To date, 18 patients from 13 families have been reported, presenting with the key clinical features of optic atrophy, peripheral neuropathy, and cerebellar atrophy. The course of the disease was highly variable ranging from severe muscular hypotonia at birth and early death to first manifestations in late childhood and survival into the fifties. Here we report on 4 patients from 2 families diagnosed with PCH who died within the first month of life from respiratory insufficiency. Patients from 1 family had pathoanatomically proven spinal motor neuron degeneration (PCH1). Using exome sequencing, we identified biallelic disease-segregating loss-of-function mutations in SLC25A46 in both families. Our study adds to the definition of the SLC25A46-associated phenotypic spectrum that includes neonatal fatalities due to PCH as the severe extreme.

Hereditary Neuropathies: Update 2017

Hereditary neuropathy is an umbrella term for a group of nonsyndromic conditions with a prevalence of approximately 1:2,500. In addition to the most frequent form, Charcot–Marie–Tooth's disease (CMT, or hereditary motor and sensory neuropathy), there are additional entities such as hereditary neuropathy with liability to pressure palsies (HNPP), hereditary motor neuropathies (HMNs), and hereditary sensory and autonomic neuropathies (HSANs). With the exception of HNPP, which is almost always caused by defects of the PMP22 gene, all other forms show genetic heterogeneity with altogether close to 100 genes involved. Mutation detection rates vary considerably, reaching up to 80% in demyelinating CMT (CMT1) but are still as low as 10 to 30% in axonal CMT (CMT2), HMN, and HSAN. Based on current information, analysis of only four genes (PMP22, GJB1, MPZ, MFN2) identifies 80 to 90% of CMT-causing mutations that can be detected in all known disease genes. For the remaining patients, parallel analysis of multiple neuropathy genes using next-generation sequencing is now replacing phenotype-oriented multistep gene-by-gene sequencing. Such approaches tend to generate a wealth of genetic information that requires comprehensive evaluation of the pathogenic relevance of identified variants. In this review, we present current classification systems, specific phenotypic clues, and genetic testing algorithms in the different subgroups of hereditary neuropathies.

Rare Variants in MME, Encoding Metalloprotease Neprilysin, Are Linked to Late-Onset Autosomal-Dominant Axonal Polyneuropathies

Axonal polyneuropathies are a frequent cause of progressive disability in the elderly. Common etiologies comprise diabetes mellitus, paraproteinaemia, and inflammatory disorders, but often the underlying causes remain elusive. Late-onset axonal Charcot-Marie-Tooth neuropathy (CMT2) is an autosomal-dominantly inherited condition that manifests in the second half of life and is genetically largely unexplained. We assumed age-dependent penetrance of mutations in a so far unknown gene causing late-onset CMT2. We screened 51 index case subjects with late-onset CMT2 for mutations by whole-exome (WES) and Sanger sequencing and subsequently queried WES repositories for further case subjects carrying mutations in the identified candidate gene. We studied nerve pathology and tissue levels and function of the abnormal protein in order to explore consequences of the mutations. Altogether, we observed heterozygous rare loss-of-function and missense mutations in MME encoding the metalloprotease neprilysin in 19 index case subjects diagnosed with axonal polyneuropathies or neurodegenerative conditions involving the peripheral nervous system. MME mutations segregated in an autosomal-dominant fashion with age-related incomplete penetrance and some affected individuals were isolated case subjects. We also found that MME mutations resulted in strongly decreased tissue availability of neprilysin and impaired enzymatic activity. Although neprilysin is known to degrade β-amyloid, we observed no increased amyloid deposition or increased incidence of dementia in individuals with MME mutations. Detection of MME mutations is expected to increase the diagnostic yield in late-onset polyneuropathies, and it will be tempting to explore whether substances that can elevate neprilysin activity could be a rational option for treatment.

Mutations in Subunits of the Activating Signal Cointegrator 1 Complex Are Associated with Prenatal Spinal Muscular Atrophy and Congenital Bone Fractures

Transcriptional signal cointegrators associate with transcription factors or nuclear receptors and coregulate tissue-specific gene transcription. We report on recessive loss-of-function mutations in two genes (TRIP4 and ASCC1) that encode subunits of the nuclear activating signal cointegrator 1 (ASC-1) complex. We used autozygosity mapping and whole-exome sequencing to search for pathogenic mutations in four families. Affected individuals presented with prenatal-onset spinal muscular atrophy (SMA), multiple congenital contractures (arthrogryposis multiplex congenita), respiratory distress, and congenital bone fractures. We identified homozygous and compound-heterozygous nonsense and frameshift TRIP4 and ASCC1 mutations that led to a truncation or the entire absence of the respective proteins and cosegregated with the disease phenotype. Trip4 and Ascc1 have identical expression patterns in 17.5-day-old mouse embryos with high expression levels in the spinal cord, brain, paraspinal ganglia, thyroid, and submandibular glands. Antisense morpholino-mediated knockdown of either trip4 or ascc1 in zebrafish disrupted the highly patterned and coordinated process of α-motoneuron outgrowth and formation of myotomes and neuromuscular junctions and led to a swimming defect in the larvae. Immunoprecipitation of the ASC-1 complex consistently copurified cysteine and glycine rich protein 1 (CSRP1), a transcriptional cofactor, which is known to be involved in spinal cord regeneration upon injury in adult zebrafish. ASCC1 mutant fibroblasts downregulated genes associated with neurogenesis, neuronal migration, and pathfinding (SERPINF1, DAB1, SEMA3D, SEMA3A), as well as with bone development (TNFRSF11B, RASSF2, STC1). Our findings indicate that the dysfunction of a transcriptional coactivator complex can result in a clinical syndrome affecting the neuromuscular system.

Distally pronounced infantile spinal muscular atrophy with severe axonal and demyelinating neuropathy associated with the S230L mutation of SMN1

Two Croatian siblings with atypical clinical findings in the presence of SMN1 gene mutations are reported. The girl presented with delayed motor development and weakness in hands and feet in her first year of life. She never stood or walked and developed scoliosis and joint contractures during childhood. Her hands and feet were non-functional when last seen at age 14 years. Her 4-year-old brother was more severely affected and had a clinical picture resembling infantile spinal muscular atrophy (SMA) type 1. He also showed unusual distally pronounced weakness and facial weakness. Both patients had no sensory deficits but gave evidence of a mixed axonal and demyelinating neuropathy with pronounced slowing in the distal nerve segments. Unexpectedly, both siblings showed a compound heterozygous SMN1 mutation (heterozygous deletion and missense mutation c.689C > T; p.S230L), thus confirming infantile SMA. In addition, next generation sequencing of 52 genes for hereditary neuropathies revealed a heterozygous missense mutation c.505T > C; p.Y169H in the SH3TC2 gene that was transmitted by the healthy father. Our observations widen the phenotypic consequences of SMN1 gene mutations and support the notion to look for additional genetic factors which may modify the clinical picture in atypical cases.

Diagnostic algorithms in Charcot-Marie-Tooth neuropathies: experiences from a German genetic laboratory on the basis of 1206 index patients

We present clinical features and genetic results of 1206 index patients and 124 affected relatives who were referred for genetic testing of Charcot-Marie-Tooth (CMT) neuropathy at the laboratory in Aachen between 2001 and 2012. Genetic detection rates were 56% in demyelinating CMT (71% of autosomal dominant (AD) CMT1/CMTX), and 17% in axonal CMT (24% of AD CMT2/CMTX). Three genetic defects (PMP22 duplication/deletion, GJB1/Cx32 or MPZ/P0 mutation) were responsible for 89.3% of demyelinating CMT index patients in whom a genetic diagnosis was achieved, and the diagnostic yield of the three main genetic defects in axonal CMT (GJB1/Cx32, MFN2, MPZ/P0 mutations) was 84.2%. De novo mutations were detected in 1.3% of PMP22 duplication, 25% of MPZ/P0, and none in GJB1/Cx32. Motor nerve conduction velocity was uniformly <38 m/s in median or ulnar nerves in PMP22 duplication, >40 m/s in MFN2, and more variable in GJB1/Cx32, MPZ/P0 mutations. Patients with CMT2A showed a broad clinical severity regardless of the type or position of the MFN2 mutation. Out of 75 patients, 8 patients (11%) with PMP22 deletions were categorized as CMT1 or CMT2. Diagnostic algorithms are still useful for cost-efficient mutation detection and for the interpretation of large-scale genetic data made available by next generation sequencing strategies.

[Myotonic dystrophies: clinical presentation, pathogenesis, diagnostics and therapy]

The autosomal-dominant myotonic dystrophies dystrophia myotonica type-1 (DM1, Curschmann-Steinert disease) and dystrophia myotonica type-2 (DM2, proximal myotonic myopathy (PROMM)), are, contrary to the non-dystrophic myotonias, progressive multisystem disorders. DM1 and DM2 are the most frequent of the muscular dystrophies. In both diseases the skeletal muscle is the most severely affected organ (weakness, wasting, myotonia, myalgia). Additionally, they manifest in the eye, heart, brain, endocrine glands, gastrointestinal tract, skin, skeleton, and peripheral nerves. Phenotypes of DM1 may be classified as congenital, juvenile, classical, or late onset. DM2 is a disorder of the middle or older age and usually has a milder course compared to DM1. DM1 is due to a CTG-repeat expansion > 50 repeats in the non-coding 3' UTR of the DMPK-gene. DM2 is caused by a CCTG-repeat expansion to 75 - 11 000 repeats in intron-1 of the CNBP/ZNF9 gene. Mutant pre-mRNAs of both genes aggregate within the nucleus (nuclear foci), which sequester RNA-binding proteins and result in an abnormal protein expression via alternative splicing in downstream effector genes (toxic RNA diseases). Other mechanisms seem to play an additional pathogenetic role. Clinical severity of DM1 increases from generation to generation (anticipation). The higher the repeat expansion the more severe the DM1 phenotype. In DM2 severity of symptoms and age at onset do not correlate with the expansion size. Contrary to DM2, there is a congenital form and anticipation in DM1.

Twenty-one years to the right diagnosis - clinical overlap of Simpson-Golabi-Behmel and Beckwith-Wiedemann syndrome

Clinical overlap makes the diagnosis of overgrowth syndromes challenging. Clinical overlap exists between Simpson-Golabi-Behmel syndrome (SGBS) and Beckwith-Wiedemann syndrome (BWS) which share pre- and postnatal overgrowth, macroglossia, umbilical hernia, organomegaly, ear lobe creases, and occurrence of embryonal tumors as characteristic features. Based on the clinical history of a patient, who was diagnosed with BWS shortly after birth and reassessed and rediagnosed with SGBS at age 21 years, particular attention should be paid to developing facial dysmorphia. In addition, we delineate further clinical findings that may allow differentiation between both conditions.

HSJ1-related hereditary neuropathies: novel mutations and extended clinical spectrum

OBJECTIVES

To determine the nature and frequency of HSJ1 mutations in patients with hereditary motor and hereditary motor and sensory neuropathies.

METHODS

Patients were screened for mutations by genome-wide or targeted linkage and homozygosity studies, whole-exome sequencing, and Sanger sequencing. RNA and protein studies of skin fibroblasts were used for functional characterization.

RESULTS

We describe 2 additional mutations in the HSJ1 gene in a cohort of 90 patients with autosomal recessive distal hereditary motor neuropathy (dHMN) and Charcot-Marie-Tooth disease type 2 (CMT2). One family with a dHMN phenotype showed the homozygous splice-site mutation c.229+1G>A, which leads to retention of intron 4 in the HSJ1 messenger RNA with a premature stop codon and loss of protein expression. Another family, presenting with a CMT2 phenotype, carried the homozygous missense mutation c.14A>G (p.Tyr5Cys). This mutation was classified as likely disease-related by several automatic algorithms for prediction of possible impact of an amino acid substitution on the structure and function of proteins. Both mutations cosegregated with autosomal recessive inheritance of the disease and were absent from the general population.

CONCLUSIONS

Taken together, in our cohort of 90 probands, we confirm that HSJ1 mutations are a rare but detectable cause of autosomal recessive dHMN and CMT2. We provide clinical and functional information on an HSJ1 splice-site mutation and report the detailed phenotype of 2 patients with CMT2, broadening the phenotypic spectrum of HSJ1-related neuropathies.

Pontocerebellar hypoplasia

Pontocerebellar hypoplasia (PCH) is a clinically and genetically heterogeneous group of autosomal recessively inherited neurodevelopmental disorders. Following the rapidly increasing number of genes identified in different subtypes, the clinical spectrum has been broadened to completely different neurological phenotypes. In this review we will address the clinical picture, neuroradiological, pathoanatomic, and genetic findings in the currently known PCH subtypes.

Congenital mirror movements: mutational analysis of RAD51 and DCC in 26 cases

OBJECTIVE

We screened a large series of individuals with congenital mirror movements (CMM) for mutations in the 2 identified causative genes, DCC and RAD51.

METHODS

We studied 6 familial and 20 simplex CMM cases. Each patient had a standardized neurologic assessment. Analysis of DCC and RAD51 coding regions included Sanger sequencing and a quantitative method allowing detection of micro rearrangements. We then compared the frequency of rare variants predicted to be pathogenic by either the PolyPhen-2 or the SIFT algorithm in our population and in the 4,300 controls of European origin on the Exome Variant Server.

RESULTS

We found 3 novel truncating mutations of DCC that segregate with CMM in 4 of the 6 families. Among the 20 simplex cases, we found one exonic deletion of DCC, one DCC mutation leading to a frameshift, 5 missense variants in DCC, and 2 missense variants in RAD51. All 7 missense variants were predicted to be pathogenic by one or both algorithms. Statistical analysis showed that the frequency of variants predicted to be deleterious was significantly different between patients and controls (p < 0.001 for both RAD51 and DCC).

CONCLUSION

Mutations and variants in DCC and RAD51 are strongly associated with CMM, but additional genes causing CMM remain to be discovered.

High mutation detection rates in cerebral cavernous malformation upon stringent inclusion criteria: one-third of probands are minors

Cerebral cavernous malformations (CCM) are prevalent vascular malformations occurring in familial autosomal dominantly inherited or isolated forms. Once CCM are diagnosed by magnetic resonance imaging, the indication for genetic testing requires either a positive family history of cavernous lesions or clinical symptoms such as chronic headaches, epilepsy, neurological deficits, and hemorrhagic stroke or the occurrence of multiple lesions in an isolated case. Following these inclusion criteria, the mutation detection rates in a consecutive series of 105 probands were 87% for familial and 57% for isolated cases. Thirty-one novel mutations were identified with a slight shift towards proportionally more CCM3 mutations carriers than previously published (CCM1: 60%, CCM2: 18%, CCM3: 22%). In-frame deletions and exonic missense variants requiring functional analyses to establish their pathogenicity were rare: An in-frame deletion within the C-terminal FERM domain of CCM1 resulted in decreased protein expression and impaired binding to the transmembrane protein heart of glass (HEG1). Notably, 20% of index cases carrying a CCM mutation were below age 10 and 33% below age 18 when referred for genetic testing. Since fulminant disease courses during the first years of life were observed in CCM1 and CCM3 mutation carriers, predictive testing of minor siblings became an issue.