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.

Feedback-controlled laser ablation for cancer treatment: comparison of On-Off and PID control strategies. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022;2022:5012-5015. [PMID: 36085688 DOI: 10.1109/embc48229.2022.9871972]

Laser ablation is a rising technique used to induce a localized temperature increment for tumor ablation. The outcomes of the therapy depend on the tissue thermal history. Monitoring devices help to assess the tissue thermal response, and their combination with a control strategy can be used to promptly address unexpected temperature changes and thus reduce unwanted thermal effects. In this application, numerical simulations can drive the selection of the laser control settings (i.e., laser power and gain parameters) and allow evaluating the thermal effects of the control strategies. In this study, the influence of different control strategies (On-Off and PID-based controls) is quantified considering the treatment time and the thermal effect on the tissue. Finite element model-based simulations were implemented to model the laser-tissue interaction, the heat-transfer, and the consequent thermal damage in liver tissue with tumor. The laser power was modulated based on the temperature feedback provided within the tumor safety margin. Results show that the chosen control strategy does not have a major influence on the extent of thermal damage but on the treatment duration; the percentage of necrosis within the tumor domain is 100% with both strategies, while the treatment duration is 630 s and 786 s for On-Off and PID, respectively. The choice of the control strategy is a trade-off between treatment duration and unwanted temperature overshoot during closed-loop laser ablation. Clinical Relevance-This work establishes that different temperature-based control of the laser ablation procedure does not have a major influence on the extent of thermal damage but on the duration of treatment.

Whole Exome Sequencing in BRCA1-2 Candidate Families: 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 (ES) 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. 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.

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.

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.

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.

AARS2-related ovarioleukodystrophy: Clinical and neuroimaging features of three new cases

INTRODUCTION

Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP), previously known as hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS) or pigmentary orthochromatic leukodystrophy (POLD), is the most frequent non-vascular adult-onset leukoencephalopathy. It is caused by autosomal dominant mutations in CSF1R gene. Recently, also autosomal recessive mutations in AARS2 gene were found to be the cause of an adult-onset leukodystrophy with axonal spheroids. Our aim was to achieve a genetic diagnosis in a cohort of CSF1R-negative patients, performing a sequence analysis of AARS2 gene.

MATERIAL AND METHODS

AARS2 sequencing was performed in 38 CSF1R-negative patients with clinical and magnetic resonance imaging (MRI) findings of adult-onset leukoencephalopathy.

RESULTS

Three patients carrying AARS2 compound heterozygous mutations have been found. All patients were female with ovarian failure and leukoencephalopathy. In 2 patients, MRI findings were consistent with previous reports while the third patient showed focal white matter (WM) lesions in the centrum semiovale and the corpus callosum in the absence of extensive involvement and rarefaction of the WM. MRI spectroscopy showed the presence of increased lactate in 2 patients, thus linking AARS2-related leukoencephalopathy with other mitochondrial leukoencephalopathies with high levels of cerebral lactate.

CONCLUSION

We recommend screening for mutations in AARS2 gene in CSF1R-negative patients, also in the absence of a clear family history and peculiar MRI findings. Our results also suggest that findings of conventional MRI and MR spectroscopy may be useful in prompting the genetic screening.

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.

A pilot study for development of a novel tool for clinical decision making to identify fallers among ophthalmic patients

Background

Falls in the elderly is a major problem. Although falls have a multifactorial etiology, a commonly cited cause of falls in older people is poor vision. This study proposes a method to discriminate fallers and non-fallers among ophthalmic patients, based on data-mining algorithms applied to health and socio-demographic information.

Methods

A group of 150 subjects aged 55 years and older, recruited at the Eye Clinic of the Second University of Naples, underwent a baseline ophthalmic examination and a standardized questionnaire, including lifestyles, general health, social engagement and eyesight problems. A subject who reported at least one fall within one year was considered as faller, otherwise as non-faller. Different tree-based data-mining algorithms (i.e., C4.5, Adaboost and Random Forest) were used to develop automatic classifiers and their performances were evaluated by assessing the receiver-operator characteristics curve estimated with the 10-fold-crossvalidation approach.

Results

The best predictive model, based on Random Forest, enabled to identify fallers with a sensitivity and specificity rate of 72.6% and 77.9%, respectively. The most informative variables were: intraocular pressure, best corrected visual acuity and the answers to the total difficulty score of the Activities of Daily Vision Scale (a questionnaire for the measurement of visual disability).

Conclusions

The current study confirmed that some ophthalmic features (i.e. cataract surgery, lower intraocular pressure values) could be associated with a lower fall risk among visually impaired subjects. Finally, automatic analysis of a combination of visual function parameters (either self-evaluated either by ophthalmological tests) and other health information, by data-mining algorithms, could be a feasible tool for identifying fallers among ophthalmic patients.

Standard versus trans-epithelial collagen cross-linking in keratoconus patients suitable for standard collagen cross-linking

PURPOSE

Evaluating the clinical results of trans-epithelial collagen cross-linking (CXL) and standard CXL in patients with progressive keratoconus.

METHODS

This prospective study comprised 20 eyes of 20 patients with progressive keratoconus. Ten eyes were treated by standard CXL and ten by trans-epithelial cross-linking (TE-CXL, epithelium on) with 1 year of follow-up. All patients underwent complete ophthalmologic testing that included pre- and postoperative uncorrected visual acuity, corrected visual acuity, spherical error, spherical equivalent, corneal astigmatism, simulated maximum, minimum, and average keratometry, coma and spherical aberration, optical pachymetry, and endothelial cell density. Intra-and postoperative complications were recorded. The solution used for standard CXL comprised riboflavin 0.1% and dextran 20.0% (Ricrolin), while the solution for TE-CXL (Ricrolin, TE) comprised riboflavin 0.1%, dextran 15.0%, trometamol (Tris), and ethylenediaminetetraacetic acid. Ultraviolet-A treatment was performed with UV-X System at 3 mW/cm(2).

RESULTS

In both the standard CXL group (ten patients, ten eyes; mean age, 30.4±7.3 years) and the TE-CXL group (ten patients, ten eyes; mean age, 28±3.8 years), uncorrected visual acuity and corrected visual acuity improved significantly after treatment. Furthermore, a significant improvement in topographic outcomes, spherical error, and spherical equivalent was observed in both groups at month 12 posttreatment. No significant variations were recorded in other parameters. No complications were noted.

CONCLUSION

A 1-year follow-up showed stability of clinical and refractive outcomes after standard CXL and TE-CXL.

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.

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.

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.

Novel PTEN mutations in neurodevelopmental disorders and macrocephaly

Somatic mutations of the phosphatase and tensin (PTEN) gene have been frequently detected in many types of human cancer. However, germline mutations can determine multiple hamartoma syndromes and, as more recently ascertained, syndromes clinically characterized by autism associated with macrocephaly. To determine whether germline mutations of PTEN may lead to different phenotypes, we screened all the nine exons of the PTEN gene in 40 patients with neurodevelopmental disorders, with or without features of autism spectrum disorder, associated with macrocephaly. Three novel de novo missense mutations were found (p.H118P, p.Y176C, p.N276S) in two severely mentally retarded patients with autism and in a subject with neurodevelopmental disorders without autistic features. Our results provide evidence that PTEN germline mutations may sustain a more wide phenotypical spectrum than previously suggested.

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.

Haploinsufficiency of TCF4 causes syndromal mental retardation with intermittent hyperventilation (Pitt-Hopkins syndrome)

Pitt-Hopkins syndrome is a rarely reported syndrome of so-far-unknown etiology characterized by mental retardation, wide mouth, and intermittent hyperventilation. By molecular karyotyping with GeneChip Human Mapping 100K SNP arrays, we detected a 1.2-Mb deletion on 18q21.2 in one patient. Sequencing of the TCF4 transcription factor gene, which is contained in the deletion region, in 30 patients with significant phenotypic overlap revealed heterozygous stop, splice, and missense mutations in five further patients with severe mental retardation and remarkable facial resemblance. Thus, we establish the Pitt-Hopkins syndrome as a distinct but probably heterogeneous entity caused by autosomal dominant de novo mutations in TCF4. Because of its phenotypic overlap, Pitt-Hopkins syndrome evolves as an important differential diagnosis to Angelman and Rett syndromes. Both null and missense mutations impaired the interaction of TCF4 with ASCL1 from the PHOX-RET pathway in transactivating an E box-containing reporter construct; therefore, hyperventilation and Hirschsprung disease in patients with Pitt-Hopkins syndrome might be explained by altered development of noradrenergic derivatives.

Unusually severe expression of craniofacial features in Aarskog-Scott syndrome due to a novel truncating mutation of theFGD1 gene

Aarskog-Scott syndrome (AAS) is a rare, clinically and genetically heterogeneous condition characterized by facial dysmorphic features, short stature, brachydactyly, and genital anomalies. The X-linked form is caused by mutations of the FGD1 gene. Although clinical manifestations and diagnostic criteria are well established, diagnosis is not simple, as the spectrum of phenotypical features may be extremely variable. Here, we report on the clinical and genetic characterization of a family in which molecular analyses revealed the inheritance of a novel truncating mutation of the FDG1 gene (c.945insC) in two affected brothers, with one of them displaying unusually severe craniofacial abnormalities. This previously unreported combination of anomalies might be due to the occurrence of two distinct disorders (AAS and hemifacial microsomia) or may represent an extension of the AAS phenotypic spectrum. Our findings highlight the phenotypic heterogeneity of AAS, supporting the opinion that the FGD1 mutations result in a broad spectrum of severity and, in some cases, may express a clinical appearance very different than typically described.

Unilateral focal polymicrogyria in a patient with classical Aarskog–Scott syndrome due to a novel missense mutation in an evolutionary conserved RhoGEF domain of the faciogenital dysplasia geneFGD1

Faciogenital dysplasia or Aarskog-Scott syndrome (AAS) is an X-linked disorder characterized by craniofacial, skeletal, and urogenital malformations and short stature. Mutations in the only known causative gene FGD1 are found in about one-fifth of the cases with the clinical diagnosis of AAS. FGD1 is a guanine nucleotide exchange factor (GEF) that specifically activates the Rho GTPase Cdc42 via its RhoGEF domain. The Cdc42 pathway is involved in skeletal formation and multiple aspects of neuronal development. We describe a boy with typical AAS and, in addition, unilateral focal polymicrogyria (PMG), a feature hitherto unreported in AAS. Sequencing of the FGD1 gene in the index case and his mother revealed the presence of a novel mutation (1396A>G; M466V), located in the evolutionary conserved alpha-helix 4 of the RhoGEF domain. M466V was not found in healthy family members, in >300 healthy controls and AAS patients, and has not been reported in the literature or mutation databases to date, indicating that this novel missense mutation causes AAS, and possibly PMG. Brain cortex malformations such as PMG could be initiated by mutations in the evolutionary conserved RhoGEF domain of FGD1, by perturbing the signaling via Rho GTPases such as Cdc42 known to cause brain malformation.

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.

Attention-deficit/hyperactivity disorder (ADHD) and variable clinical expression of Aarskog-Scott syndrome due to a novelFGD1 gene mutation (R408Q)

Mutations of the FGD1 gene are responsible for a significant proportion of patients with Aarskog-Scott syndrome (AAS), an X-linked disorder characterized by short stature, brachydactyly, urogenital abnormalities, and a typical dysmorphic facial appearance. Although mental retardation does not occur significantly in AAS, this condition has been described associated with various degrees of mental impairment and/or behavioral disorders in some patients. In particular, attention deficit hyperactivity disorder (ADHD) is reported as a common characteristic of AAS. However, AAS/ADHD reported patients have been only clinically described, and diagnosis never has been confirmed on molecular basis. We present here a unique case of a 16-years-old patient presenting with ADHD, lower intelligence quotient, and dysmorphic features. Although the clinical features were not completely typical of AAS, genetic analysis demonstrated a novel FGD1 missense mutation (R408Q). The case we report confirms the highly variable expressivity of AAS and first documents that the FGD1 gene may play a role in ADHD susceptibility. We suggest that FGD1 analysis may be adequate in ADHD patients who exhibit dysmorphic features suggestive of AAS, also in the absence of the full phenotypical spectrum.

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.

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.

Retinochoroidal atrophy in two adult patients with Angelman syndrome

We describe a new ocular finding, retinochoroidal atrophy (RCA), associated with optic disk paleness in two adult patients with Angelman syndrome (AS) due to maternal 15q11-13 deletion. The ocular involvement described in children with AS consists iris and choroids hypopigmentation due to loss of function of one copy of P gene involved in maternal deletion. The loss of one copy of the same gene of paternal origin leads to a similar ocular phenotype as in Prader-Willi syndrome (PWS). However to our knowledge, RCA has never been described before in PWS, suggesting that other maternally expressed genes, particularly UBE3A, could be responsible for the retinal changes observed in the adult AS phenotype. Although, further investigations would be necessary to better understand the role of the UBE3A in the retina, the findings reported here should prompt a systematic ophthalmologic evaluation adult patients with AS in order to establish the real incidence of RCA and prevent further disability in these patients.

Septo-optic dysplasia with digital anomalies associated with maternal multidrug abuse during pregnancy

We describe a 16-year-old female affected by septo-optic dysplasia (SOD) with digital anomalies as additional feature. This rare developmental anomaly of midline brain structures can result from different pathogenetical events, including mutations of the homeo box gene HESX1, recently suggested as the etiological cause at least in a subset of patients. The absence of mutational involvement of this gene in our patient led us to consider, in alternative terms of pathogenesis, the maternal multidrug abuse occurring during pregnancy. Our report, in accord with previous experimental evidences, points out that illicit drug use might have played a causative role in brain development anomalies, thus our patient could represent an additional case of birth defects caused by a prenatal toxic exposure. The neurologic abnormalities and the clinical history of the patient are extensively reviewed. The need to include the SOD phenotype amongst the possible teratogenic effects of multidrug abuse is evidenced.

Mutations in the RYR1 gene in Italian patients at risk for malignant hyperthermia: evidence for a cluster of novel mutations in the C-terminal region

Mutations in the ryanodine receptor type 1 (RYR1) gene are associated with Malignant Hyperthermia (MH) and Central Core Disease (CCD). We report here on the molecular analysis of the RYR1 gene in Italian families referred as potential cases of MH or in patients with CCD or multicore/minicore myopathy. Of a total of 20 individuals with mutations in the RYR1 gene, 14 were part of a group of 47 MH susceptible (MHS) patients, 4 of 34 individuals diagnosed as MH equivocal (MHE), and 2 were patients diagnosed with minicore myopathy and CCD, respectively. Mutations were found to segregate with the MHS or MHE phenotype within the families of the probands. A discordance between phenotype and genotype was observed in a family where a mutation detected in an MHS proband was also found in the father who had been diagnosed MH normal (MHN) at the IVCT. In addition to known mutations, seven novel mutations were found, five of which occurred in exons encoding the C-terminal region of RYR1. These results indicate that the C-terminal region of RYR1 represents an additional hot spot for mutations in patients with MH, similar to what has been reported for patients with CCD.

A Rett syndrome MECP2 mutation that causes mental retardation in men

OBJECTIVE

To characterize the clinical features of a new type of X-linked mental retardation associated with MECP2 mutation in the index family.

BACKGROUND

MECP2 mutations, originally described in a high percentage of patients with classic Rett syndrome, were considered lethal in men. The authors recently described a novel A140V MECP2 missense mutation in an Italian family with X-linked semidominant mental retardation.

METHODS

The neurologic features of six symptomatic relatives (two women and four men) carrying the mutation were compiled. Laboratory investigations included EEG, EMG, conduction velocity (CV) of peripheral nerves, brain MRI, and (1)H-MR spectroscopy.

RESULTS

Mental retardation and signs of neurologic impairment were present in all the affected members, but more pronounced in men. Neurologic features included slowly progressive spastic paraparesis/pyramidal signs (6/6), distal atrophy of the legs (6/6), ataxia (2/6), and postural tremor of the hands (3/6). Speech was preserved (6/6) but was dysarthric in the oldest brothers (2/6). Mild dysmorphic features were present in all cases.

CONCLUSION

The neurologic disorder associated with A140V MECP2 mutation is not necessarily lethal in men, but they are more severely affected than women of the same family.

Possible case of Pitt-Hopkins syndrome in sibs

In this article, we describe two sibs, a brother and sister, with severe mental retardation and multiple congenital anomalies including "coarse" facial features, short stature, seizures, hypertrichosis, short great toes, and overbreathing. Comparison of these patients with previous reports suggests that they could represent the first familial cases of the Pitt-Hopkins syndrome. The recurrence in sibs within the same family supports autosomal recessive inheritance for the condition. Variable expression of the respiratory symptoms, which has not been reported earlier, is underlined.

Additional case of Marden-Walker syndrome: support for the autosomal-recessive inheritance adn refinement of phenotype in a surviving patient

In this report, we present a 14-year-old girl, born to consanguineous parents, who presented with severe mental retardation, hypotonia, short stature, and congenital joint contractures. The craniofacial features were scaphocephaly, thin/long and immobile face, marked hypoplasia of the midface, temporal narrowness, blepharophimosis, palpebral ptosis, and strabismus. The combination of such a distinctive craniofacial appearance and psychomotor retardation allows us to recognize a new case of the Marden-Walker syndrome. Our patient represents one of the rare cases in which consanguineous mating supports the autosomal-recessive pattern of inheritance of this condition. Furthermore, through refining the phenotype of a surviving patient, this report may contribute to a better recognition of this disorder in older affected children.

MECP2 mutation in male patients with non-specific X-linked mental retardation

In contrast to the preponderance of affected males in families with X-linked mental retardation, Rett syndrome (RTT) is a neurological disorder occurring almost exclusively in females. The near complete absence of affected males in RTT families has been explained by the lethal effect of an X-linked gene mutation in hemizygous affected males. We report here on a novel mutation (A140V) in the MECP2 gene detected in one female with mild mental retardation. In a family study, the A140V mutation was found to segregate in the affected daughter and in four adult sons with severe mental retardation. These results indicate that MECP2 mutations are not necessarily lethal in males and that they can be causative of non-specific X-linked mental retardation.