The Prevalence of Clinical Features in Patients with Aarskog-Scott Syndrome and Assessment of Genotype-Phenotype Correlation: A Systematic Review.

Aarskog-Scott syndrome is a genetically and clinically heterogeneous rare condition caused by a pathogenic variant in the FGD1 gene. A systematic review was carried out to analyse the prevalence of clinical manifestations found in patients, as well as to evaluate the genotype-phenotype correlation. The results obtained show that clinical findings of the craniofacial, orthopaedic, and genitourinary tract correspond to the highest scores of prevalence. The authors reclassified the primary, secondary, and additional criteria based on their prevalence. Furthermore, it was possible to observe, in accordance with previous reports, that the reported phenotypes do not present a direct relation to the underlying genotypes.

The Variable Expression of a Novel MBD5 Gene Frameshift Mutation in an Italian Family.

Haploinsufficiency of the methyl-CpG-binding domain protein 5 (MBD5) gene is reported as a cause of an autosomal dominant type of cognitive disability (MRD1) and autism spectrum disorder through large deletions involving multiple genes or point mutations, ultimately leading to haploinsufficiency in both cases. However, relatively few reports have been published on the phenotypical spectrum resulting from point mutations.We report here on a novel heterozygous frameshift variant in the MBD5 gene [c.2579del; p.(Lys860Argfs*11)] in a family in which the typical signs associated with pathogenic variants were expressed with different degrees of severity in the clinical presentation of the carrier individuals.Our findings, adding a novel mutation to the mutational spectrum, further support the relevance of the MBD5 gene as one of the main molecular mechanisms involved in the pathogenesis of intellectual disability and contribute to the characterization of the genotype-phenotype correlations.

Case report: The CCDC103 variant causes ultrastructural sperm axonemal defects and total sperm immotility in a professional athlete without primary ciliary diskinesia.

Primary ciliary dyskinesia (PCD) is an inherited autosomal-recessive disorder characterized by abnormal ciliary motion, due to a defect in ciliary structure and/or function. This genetic condition leads to recurrent upper and lower respiratory infections, bronchiectasis, laterality defect, and subfertility. Male infertility is often associated with PCD, since the ultrastructure of the axoneme in the sperm tail is similar to that of the motile cilia of respiratory cells. We present the first reported case of a male patient from a non-consanguineous Italian family who exhibited a severe form of asthenozoospermia factor infertility but no situs inversus and absolutely no signs of the clinical respiratory phenotype, the proband being a professional basketball player. Whole-exome sequencing (WES) has identified a homozygote mutation (CCDC103 c.461 A>C, p.His154Pro) in the proband, while his brother was a heterozygous carrier for this mutation. Morphological and ultrastructural analyses of the axoneme in the sperm flagellum demonstrated the complete loss of both the inner and outer dynein arms (IDA and ODA, respectively). Moreover, immunofluorescence of DNAH1, which is used to check the assembly of IDA, and DNAH5, which labels ODA, demonstrated that these complexes are absent along the full length of the flagella in the spermatozoa from the proband, which was consistent with the IDA and ODA defects observed. Noteworthy, TEM analysis of the axoneme from respiratory cilia showed that dynein arms, although either IDAs and/or ODAs seldom missing on some doublets, are still partly present in each observed section. This case reports the total sperm immotility associated with the CCDC103 p.His154Pro mutation in a man with a normal respiratory phenotype and enriches the variant spectrum of ccdc103 variants and the associated clinical phenotypes in PCD, thus improving counseling of patients about their fertility and possible targeted treatments.

CNTNAP2 and NRXN1 are mutated in autosomal-recessive Pitt-Hopkins-like mental retardation and determine the level of a common synaptic protein in Drosophila.

Heterozygous copy-number variants and SNPs of CNTNAP2 and NRXN1, two distantly related members of the neurexin superfamily, have been repeatedly associated with a wide spectrum of neuropsychiatric disorders, such as developmental language disorders, autism spectrum disorders, epilepsy, and schizophrenia. We now identified homozygous and compound-heterozygous deletions and mutations via molecular karyotyping and mutational screening in CNTNAP2 and NRXN1 in four patients with severe mental retardation (MR) and variable features, such as autistic behavior, epilepsy, and breathing anomalies, phenotypically overlapping with Pitt-Hopkins syndrome. With a frequency of at least 1% in our cohort of 179 patients, recessive defects in CNTNAP2 appear to significantly contribute to severe MR. Whereas the established synaptic role of NRXN1 suggests that synaptic defects contribute to the associated neuropsychiatric disorders and to severe MR as reported here, evidence for a synaptic role of the CNTNAP2-encoded protein CASPR2 has so far been lacking. Using Drosophila as a model, we now show that, as known for fly Nrx-I, the CASPR2 ortholog Nrx-IV might also localize to synapses. Overexpression of either protein can reorganize synaptic morphology and induce increased density of active zones, the synaptic domains of neurotransmitter release. Moreover, both Nrx-I and Nrx-IV determine the level of the presynaptic active-zone protein bruchpilot, indicating a possible common molecular mechanism in Nrx-I and Nrx-IV mutant conditions. We therefore propose that an analogous shared synaptic mechanism contributes to the similar clinical phenotypes resulting from defects in human NRXN1 and CNTNAP2.

Ethical, Legal and Social Issues (ELSI) Associated with Non-Invasive Prenatal Testing: Reflections on the Evolution of Prenatal Diagnosis and Procreative Choices.

New technologies such as non-invasive prenatal testing (NIPT), capable of analyzing cell-free fetal DNA in the maternal bloodstream, have become increasingly widespread and available, which has in turn led to ethical and policy challenges that need addressing. NIPT is not yet a diagnostic tool, but can still provide information about fetal genetic characteristics (including sex) very early in pregnancy, and there is no denying that it offers valuable opportunities for pregnant women, particularly those at high risk of having a child with severe genetic disorders or seeking an alternative to invasive prenatal testing. Nonetheless, the ethical, legal and social implications (ELSI) include multiple aspects of informed decision-making, which can entail risks for the individual right to procreative autonomy, in addition to the potential threats posed by sex-selective termination of pregnancy (in light of the information about fetal sex within the first trimester), and the stigmatization and discrimination of disabled individuals. After taking such daunting challenges into account and addressing NIPT-related medicolegal complexities, the review's authors highlight the need for an ethically and legally sustainable framework for the implementation of NIPT, which seems poised to become a diagnostic tool, as its scope is likely to broaden in the near future.

Corrigendum: Exome Sequencing in BRCA1-2 Candidate Familias: The Contribution of Other Cancer Susceptibility Genes.

[This corrects the article DOI: 10.3389/fonc.2021.649435.].

Exome sequencing in BRCA1-2 candidate familias: the contribution of other cancer susceptibility genes

Hereditary Breast and Ovarian Cancer (HBOC) syndrome is a condition in which the risk of breast and ovarian cancer is higher than in the general population. The prevalent pathogenesis is attributable to inactivating variants of the BRCA1-2 highly penetrant genes, however, other cancer susceptibility genes may also be involved. By Exome Sequencing (WES) we analyzed a series of 200 individuals selected for genetic testing in BRCA1-2 genes according to the updated National Comprehensive Cancer Network (NCCN) guidelines. Analysis by MLPA was performed to detect large BRCA1-2 deletions/duplications. Focusing on BRCA1-2 genes, data analysis identified 11 cases with pathogenic variants (4 in BRCA1 and 7 in BRCA1-2) and 12 with uncertain variants (7 in BRCA1 and 5 in BRCA2). Only one case was found with a large BRCA1 deletion. Whole exome analysis allowed to characterize pathogenic variants in 21 additional genes: 10 genes more traditionally associated to breast and ovarian cancer (ATM, BRIP1, CDH1, PALB2, PTEN, RAD51C, and TP53) (5% diagnostic yield) and 11 in candidate cancer susceptibility genes (DPYD, ERBB3, ERCC2, MUTYH, NQO2, NTHL1, PARK2, RAD54L, and RNASEL). In conclusion, this study allowed a personalized risk assessment and clinical surveillance in an increased number of HBOC families and to broaden the spectrum of causative variants also to candidate non-canonical genes.

Novel Pathogenic Variants of the AIRE Gene in Two Autoimmune Polyendocrine Syndrome Type I Cases with Atypical Presentation: Role of the NGS in Diagnostic Pathway and Review of the Literature.

Background. Autoimmune polyglandular syndrome type 1 (APS-1) with or without reversible metaphyseal dysplasia is a rare genetic disorder due to inactivating variants of the autoimmune regulator, AIRE, gene. Clinical variability of APS-1 relates to pleiotropy, and the general dysfunction of self-tolerance to organ-specific antigens and autoimmune reactions towards peripheral tissues caused by the underlying molecular defect. Thus, early recognition of the syndrome is often delayed, mostly in cases with atypical presentation, and the molecular confirm through the genetic analysis of the AIRE gene might be of great benefit. Methods. Our methods were to investigate, with a multigene panel next generation sequencing approach, two clinical cases, both presenting with idiopathic hypoparathyroidism, also comprising the AIRE gene; as well as to comment our findings as part of a more extensive review of literature data. Results. In the first clinical case, two compound heterozygote pathogenic variants of the AIRE gene were identified, thus indicating an autosomal recessive inheritance of the disease. In the second case, only one AIRE gene variant was found and an atypical dominant negative form of APS-1 suggested, later confirmed by further medical ascertainments. Conclusions. APS-1 might present with variable and sometimes monosymptomatic presentations and, if not recognized, might associate with severe complications. In this context, next generation diagnostics focused on a set of genes causative of partially overlapping disorders may allow early diagnosis.

Late-onset Lennox-Gastaut syndrome in a patient with 15q11.2-q13.1 duplication.

The 4 Mb 15q11-q13 region is prone to structural rearrangements. Deletions have been identified among the leading causes for genetic diseases such as the Prader-Willi and Angelman syndromes, while duplications, occurring preferentially on the maternal chromosome, produce a typical phenotype that includes mental retardation, language delay, seizures and autism. Although a number of such patients have been reported, however, there is a paucity of information about their clinical outcomes in adult age. We report on a 33-year-old female with a microduplication of 15q11-q13 detected by array-CGH analysis, with particular reference to the epilepsy phenotype, characterized as a late-onset Lennox-Gastaut syndrome.

Muscle biopsy and in vitro contracture test in subjects with idiopathic HyperCKemia.

BACKGROUND: Persistent high creatine kinase (CK) levels may reflect underlying subclinical myopathies. In most cases, pathogenesis is unknown and clinical management is unclear. Though clinically asymptomatic, these subjects are potentially susceptible to malignant hyperthermia. METHODS: The authors analyzed 37 subjects with persistent elevation of CK without significant weakness or other neurologic symptoms. Neurologic examination was performed according to manual muscle testing. Muscle biopsy and the in vitro contracture test were performed in all subjects. RESULTS: Twenty-three subjects (51.1%) were completely asymptomatic. The others had minor symptoms such as occasional cramps (11 subjects, 24.4%), fatigue (5 subjects, 11.1%), a combination of cramps and fatigue (5 subjects, 11.1%), and muscle pain (1 case, 2.2%). Muscle biopsy enabled precise diagnosis in 3 cases and was normal in 3 cases. The more frequent changes were variation in fiber size (31.1%), a combination of nuclear internalization and variation in fiber size (26.6%), nuclear internalization (6.6%), minor mitochondrial changes (4.4%), and neurogenic atrophy (4.4%). Immunocytochemical analysis was normal in all patients. In vitro contracture testing detected one malignant hyperthermia-susceptible and one malignant hyperthermia-equivocal subject. CONCLUSIONS: The evidence of malignant hyperthermia susceptibility by in vitro contracture test seems to be relatively infrequent among subjects with idiopathic hyperCKemia, but the incidence of true malignant hyperthermia in idiopathic hyperCKemia is unknown. Muscle biopsy should be considered a useful, though not very sensitive, diagnostic tool in idiopathic hyperCKemia, because it enables potentially treatable disorders, such as inflammatory myopathies, to be discovered. No uniform morphologic finding typical of idiopathic hyperCKemia or malignant hyperthermia susceptibility was identified by muscle biopsy.

A truncation in the RYR1 gene associated with central core lesions in skeletal muscle fibres.

A novel single-nucleotide deletion in exon 100 of the RYR1 gene, corresponding to deletion of nucleotide 14,510 in the human RyR1 mRNA (c14510delA), was identified in a man with malignant hyperthermia and in his two daughters who were normal for malignant hyperthermia. This deletion results in a RyR1 protein lacking the last 202 amino acid residues. All three subjects heterozygotic for the mutated allele presented with a prevalence of type 1 fibres with central cores, although none experienced clinical signs of myopathy. Expression of the truncated protein resulted in non-functional RYR1 calcium release channels. Expression of wild-type and RyR1(R4836fsX4838) proteins resulted in heterozygotic release channels with overall functional properties similar to those of wild-type RyR1 channels. Nevertheless, small differences in sensitivity to calcium and caffeine were observed in heterotetrameric channels, which also presented an altered assembly/stability in sucrose-gradient centrifugation analysis. Altogether, these data suggest that altered RYR1 tetramer assembly/stability coupled with subtle chronic changes in Ca2+ homoeostasis over the long term may contribute to the development of core lesions and incomplete malignant hyperthermia susceptibility penetrance in individuals carrying this novel RYR1 mutation.

Complete clinical and functional recovery following low-dose methotrexate related paraparesis in a patient with compound c.1298A>C AND c.677C>T MTHFR polymorphism: A case report.

RATIONALE: The mechanisms of action of MTX (methotrexate) in the treatment of RA (rheumatoid arthritis) and PsA (psoriatic arthritis) is related to its antifolic activity, due to the high affinity for enzymes that require folate cofactors as dihydrofolate reductase and to the anti-inflammatory activity derivated from the inhibition of thymidylate synthetase that leads to the over-production of adenosine. PATIENT CONCERNS: Our patient was a 41-year-old female, affected by PsA in treatment since 2 years with low-dose methylprednisolone and low-dose subcutaneous MTX. The treatment was effective. The patient subacutely developed a severe paraparesis with impossibility of gait or standing without aid and was admitted to a Neurology Department where the cause of the paraparesis was not clear in spite of accurate radiological neurophysiologic and laboratory tests. Therefore, she was admitted in a rehabilitation unit. DIAGNOSIS AND INTERVENTIONS: Paraparesis in PsA patient in treatment with methotrexate. MTX toxicity was hypothesized; therefore the drug was discontinued while i.m. folic acid and cyanocobalamin were administered for 20 days. The diagnosis was clinical, based on neurological examination (paraparesis) and on the chronic use of MTX (hypothesis of toxicity). OUTCOMES: The patient obtained a complete resolution of paraparesis. Genetic analyses showed associated a compound heterozygosity for the c.1298A>C and c.677C>T variants of methylenetetrahydrofolate reductase (MTHFR) gene. LESSONS: Neurological side effects of MTX are uncommon. In literature no previous case of MTX induced paraparesis in patients treated with low-dose MTX for chronic arthritis has been described. The association between the gene polymorphisms of MTHFR (c.1298A>C and c.677C>T) and MTX toxicity in arthritis patients is confirmed. The case also confirms that folates are a precious antidote of MTX toxicity.

Frequency and localization of mutations in the 106 exons of the RYR1 gene in 50 individuals with malignant hyperthermia.

Malignant hyperthermia (MH) is a dominantly inherited pharmacogenetic condition that manifests as a life-threatening hypermetabolic reaction when a susceptible individual is exposed to common volatile anesthetics and depolarizing muscle relaxants. Although MH appears to be genetically heterogeneous, RYR1 is the main candidate for MH susceptibility. However, since molecular analysis is generally limited to exons where mutations are more frequently detected, these are routinely found only in 30-50% of susceptible subjects. In this study the entire RYR1 coding region was analyzed in a cohort of 50 Italian MH susceptible (MHS) subjects. Thirty-one mutations, 16 of which were novel, were found in 43 individuals with a mutation detection rate of 86%, the highest reported for RYR1 in MH so far. These data provide clear evidence that mutations in the RYR1 gene are the predominant cause of MH.

Cortical damage in brains of patients with adult-form of myotonic dystrophy type 1 and no or minimal MRI abnormalities.

OBJECTIVE: To evaluate, by using quantitative MRI metrics, subtle cortical changes in brains of patients with the adult form of myotonic dystrophy type I (DM1) who showed no or minimal abnormalities on MRI. BACKGROUND: DM1 is an autosomal dominant multisystem disorder caused by the expansion of CTG repeats in the myotonic dystrophy-protein kinase gene. Mild to severe involvement of the CNS can be part of the clinical features of the disease. Several MRI studies have demonstrated that both focal white matter (WM) lesions and diffuse grey matter atrophy can be found in the brains of DM1 patients. However, whether these two processes are related or may occur independently is not clear. DESIGN/METHODS: Ten genetically-proven DM1 patients who showed no or minimal abnormalities on MRI underwent a new brain MRI examination to obtain computerized measures of total and regional brain volumes normalized to head size and regional measurements of the magnetization transfer ratio (MTr). RESULTS: Normalized brain volumes (NBV) were significantly (p < 0.0001) lower in DM1 subjects than in a group of age- and sex-matched normal controls. Normalized cortical volumes (NCV) also were lower (p = 0.003) in DM1 subjects than in normal controls, whereas normalized WM volumes were not different between the two groups (p = 0.3). In agreement with this, values of MTr in the neocortex (cortical-MTr) were significantly (p = 0.006) lower in DM1 patients than in normal controls and this difference was not found in the WM tissue (p = 0.8). CONCLUSIONS: Neocortical damage seems to be evident in the absence of visible WM lesions suggesting that a neocortical pathology, unrelated to WM lesion formation, occurs in DM1 brains.

Molecular Dissection Using Array Comparative Genomic Hybridization and Clinical Evaluation of An Infertile Male Carrier of An Unbalanced Y;21 Translocation: A Case Report and Review of The Literature.

Chromosomal defects are relatively frequent in infertile men however, translocations between the Y chromosome and autosomes are rare and less than 40 cases of Y-autosome translocation have been reported. In particular, only three individuals has been described with a Y;21 translocation, up to now. We report on an additional case of an infertile man in whom a Y;21 translocation was associated with the deletion of a large part of the Y chromosome long arm. Applying various techniques, including conventional cytogenetic procedures, fluorescence in situ hybridisation (FISH) analysis and array comparative genomic hybridization (array-CGH) studies, we identified a derivative chromosome originating from a fragment of the short arm of the chromosome Y translocated on the short arm of the 21 chromosome. The Y chromosome structural rearrangement resulted in the intactness of the entire short arm, including the sex-determining region Y (SRY) and the short stature homeobox (SHOX) loci, although translocated on the 21 chromosome, and the loss of a large part of the long arm of the Y chromosome, including azoospermia factor-a (AZFa), AZFb, AZFc and Yq heterochromatin regions. This is the first case in which a (Yp;21p) translocation has been ascertained using an array-CGH approach, thus reporting details of such a rearrangement at higher resolution.

Phenotypic and molecular characterisation of the Aarskog-Scott syndrome: a survey of the clinical variability in light of FGD1 mutation analysis in 46 patients.

Faciogenital dysplasia or Aarskog-Scott syndrome (AAS) is a genetically heterogeneous developmental disorder. The X-linked form of AAS has been ascribed to mutations in the FGD1 gene. However, although AAS may be considered as a relatively frequent clinical diagnosis, mutations have been established in few patients. Genetic heterogeneity and the clinical overlap with a number of other syndromes might explain this discrepancy. In this study, we have conducted a single-strand conformation polymorphism (SSCP) analysis of the entire coding region of FGD1 in 46 AAS patients and identified eight novel mutations, including one insertion, four deletions and three missense mutations (19.56% detection rate). One mutation (528insC) was found in two independent families. The mutations are scattered all along the coding sequence. Phenotypically, all affected males present with the characteristic AAS phenotype. FGD1 mutations were not associated with severe mental retardation. However, neuropsychiatric disorders, mainly behavioural and learning problems in childhood, were observed in five out of 12 mutated individuals. The current study provides further evidence that mutations of FGD1 may cause AAS and expands the spectrum of disease-causing mutations. The importance of considering the neuropsychological phenotype of AAS patients is discussed.

Autonomic dysfunction in mental retardation and spastic paraparesis with MECP2 mutation.

Autonomic nervous system involvement in female patients with classic Rett syndrome usually manifests as breathing abnormalities, peripheral vasomotor disturbances, and cardiac sympathetic imbalance, the latter a possible cause of sudden death. MECP2 gene mutations responsible for Rett syndrome have also been found in male patients with mental retardation, sometimes associated with different neurologic abnormalities. However, autonomic nervous system functions have never been investigated in male patients with X-linked mental retardation owing to MECP2 mutations. We studied heart rate variability, a marker of autonomic activity, in a family with the MECP2 mutation in male patients, one of whom had died suddenly. Cardiovascular features similar to those observed in a Rett syndrome variant with preserved speech were found, suggesting sympathetic imbalance.

The first Italian patient with oculopharyngodistal myopathy: case report and considerations on differential diagnosis.

Oculopharyngodistal myopathy is a clinicopathologically distinct muscular disease. The underlying genetic defect has not been identified. We report here a 43-year old woman with asymmetric bilateral ptosis, dysphonia, swallowing difficulties, and weakness of the distal leg muscles. Serum creatine kinase was moderately increased. Electromyography revealed myopathic changes and myotonic discharges. Both cardiologic and pneumologic evaluation did not reveal abnormalities. Muscle computed tomography images showed adipose tissue replacement of abdominis rectus, lateral vastus, adductor magnus, and both the posterior and anterior compartment muscles below the knee, with prevalent involvement of medial gastrocnemius muscle. Muscle biopsy uncovered changes in fiber size and the presence of atrophic fibers with rimmed vacuoles of varying diameter, and core-like structures in type I fibers. Diagnosis was performed according to clinical and histopathologic findings, which were fully consistent with the other reported patients, and on the genetic exclusion of similar conditions such as oculopharyngeal muscular dystrophy, myotonic dystrophy type 1 and multi-minicore disease associated to RYR1 mutations. Differential diagnosis with mitochondrial myopathies, facioscapulohumeral muscular dystrophy and distal myopathies was also considered. This is the first Italian case of oculopharyngodistal myopathy, further suggesting the worldwide distribution of this rare neuromuscular disorder.