Female carrier of RPGR mutation presenting with high myopia

BACKGROUND

Inherited retinopathies can initially present with high refractive error in the first decade of life, before accompanying signs or symptoms are evident.

CASE PRESENTATION

A 4-year-old girl with high myopia (S-12.00 C-4.00 × 20 in the right and S-14.50 C-2.75 × 160 in the left eye), moderate visual acuity (0.3 logMAR in the right and 0.4 logMAR in the left eye), and left esotropia, presented with unremarkable past medical history and no family history of high refractive error or low vision. In optical coherence tomography imaging, macular thinning was evident, while morphology was normal. Full-field electroretinogram revealed normal implicit time recordings with reduced amplitudes in scotopic and photopic conditions. Fundus autofluorescence showed a radial pattern in both eyes. During a 5-year follow-up, significant myopia progression ensued (S-17.25 C-3.00 × 20 in the right and S-17.25 C-2.00 × 160 in the left eye), with a corresponding increase in axial length and an unchanged visual acuity. Whole-exome sequencing revealed a heterozygous termination codon variant c.212C>G (p.Ser71Ter) in RPGR, considered to be pathogenic. Segregation analysis precluded the variation in the mother and sister. A random pattern of X-chromosome inactivation was detected in the proband, without X-chromosome inactivation deviation.

CONCLUSION

This is the second report associating this specific RPGR mutation with high myopia and the first report to identify it in a female proband. This case provides additional evidence on the genotypic-phenotypic correlation between RPGR c.212C>G mutation and high myopia.

X-linked hypophosphatemia due to a de novo novel splice-site variant in a 7-year-old girl with scaphocephaly, Chiari syndrome type I and syringomyelia

X-linked hypophosphatemia (XLH) is a rare X-linked dominant inherited disorder caused by loss-of-function variants in the PHEX gene and characterized by renal phosphate wasting, hypophosphatemia, abnormal vitamin D metabolism, growth retardation and lower limb deformities. We describe a case of XLH-rickets in a 7-year-old girl with scaphocephaly, Chiari syndrome type I and syringomyelia, with a de novo non-canonical splice variant (c.1080-3C > G) in intron 9 of the PHEX gene, that has not been previously described.

Unveiling the crucial neuronal role of the proteasomal ATPase subunit gene PSMC5 in neurodevelopmental proteasomopathies

Neurodevelopmental proteasomopathies represent a distinctive category of neurodevelopmental disorders (NDD) characterized by genetic variations within the 26S proteasome, a protein complex governing eukaryotic cellular protein homeostasis. In our comprehensive study, we identified 23 unique variants in PSMC5 , which encodes the AAA-ATPase proteasome subunit PSMC5/Rpt6, causing syndromic NDD in 38 unrelated individuals. Overexpression of PSMC5 variants altered human hippocampal neuron morphology, while PSMC5 knockdown led to impaired reversal learning in flies and loss of excitatory synapses in rat hippocampal neurons. PSMC5 loss-of-function resulted in abnormal protein aggregation, profoundly impacting innate immune signaling, mitophagy rates, and lipid metabolism in affected individuals. Importantly, targeting key components of the integrated stress response, such as PKR and GCN2 kinases, ameliorated immune dysregulations in cells from affected individuals. These findings significantly advance our understanding of the molecular mechanisms underlying neurodevelopmental proteasomopathies, provide links to research in neurodegenerative diseases, and open up potential therapeutic avenues.

The Effect of Maternal Diet and Physical Activity on the Epigenome of the Offspring

The aim of this review was to examine the current literature regarding the effect of maternal lifestyle interventions (i.e., diet and physical activity) on the epigenome of the offspring. PubMed, Scopus and Cochrane-CENTRAL were screened until 8 July 2023. Only randomized controlled trials (RCTs) where a lifestyle intervention was compared to no intervention (standard care) were included. Outcome variables included DNA methylation, miRNA expression, and histone modifications. A qualitative approach was used for the consideration of the studies' results. Seven studies and 1765 mother-child pairs were assessed. The most common types of intervention were dietary advice, physical activity, and following a specific diet (olive oil). The included studies correlated the lifestyle and physical activity intervention in pregnancy to genome-wide or gene-specific differential methylation and miRNA expression in the cord blood or the placenta. An intervention of diet and physical activity in pregnancy was found to be associated with slight changes in the epigenome (DNA methylation and miRNA expression) in fetal tissues. The regions involved were related to adiposity, metabolic processes, type 2 diabetes, birth weight, or growth. However, not all studies showed significant differences in DNA methylation. Further studies with similar parameters are needed to have robust and comparable results and determine the biological role of such modifications.

Bi-allelic genetic variants in the translational GTPases GTPBP1 and GTPBP2 cause a distinct identical neurodevelopmental syndrome

The homologous genes GTPBP1 and GTPBP2 encode GTP-binding proteins 1 and 2, which are involved in ribosomal homeostasis. Pathogenic variants in GTPBP2 were recently shown to be an ultra-rare cause of neurodegenerative or neurodevelopmental disorders (NDDs). Until now, no human phenotype has been linked to GTPBP1. Here, we describe individuals carrying bi-allelic GTPBP1 variants that display an identical phenotype with GTPBP2 and characterize the overall spectrum of GTP-binding protein (1/2)-related disorders. In this study, 20 individuals from 16 families with distinct NDDs and syndromic facial features were investigated by whole-exome (WES) or whole-genome (WGS) sequencing. To assess the functional impact of the identified genetic variants, semi-quantitative PCR, western blot, and ribosome profiling assays were performed in fibroblasts from affected individuals. We also investigated the effect of reducing expression of CG2017, an ortholog of human GTPBP1/2, in the fruit fly Drosophila melanogaster. Individuals with bi-allelic GTPBP1 or GTPBP2 variants presented with microcephaly, profound neurodevelopmental impairment, pathognomonic craniofacial features, and ectodermal defects. Abnormal vision and/or hearing, progressive spasticity, choreoathetoid movements, refractory epilepsy, and brain atrophy were part of the core phenotype of this syndrome. Cell line studies identified a loss-of-function (LoF) impact of the disease-associated variants but no significant abnormalities on ribosome profiling. Reduced expression of CG2017 isoforms was associated with locomotor impairment in Drosophila. In conclusion, bi-allelic GTPBP1 and GTPBP2 LoF variants cause an identical, distinct neurodevelopmental syndrome. Mutant CG2017 knockout flies display motor impairment, highlighting the conserved role for GTP-binding proteins in CNS development across species.

Beckwith-Wiedemann syndrome with multiple hepatic and cutaneous hemangiomas in a female patient of Albanian origin: Diagnostic and therapeutic considerations

We describe a 2-month-old female infant with macroglossia, macrosomia, omphalocele, neonatal hypoglycemia, earlobe creases, low nasal bridge, midface retrusion, syndromic facies and multiple cutaneous and hepatic hemangiomas (HH). Genetic evaluation confirmed the diagnosis of Beckwith-Wiedemann Syndrome (BWS) with mosaic uniparental disomy 11 as the underlying genetic mechanism suggested by partial hypermethylation of H19/IGF2:IG-DMR and partial hypomethylation of KCNQ1OT1:TSS-DMR on chromosome 11p15.5. Pediatric endocrinology and cardiology assessments were normal. No malignant liver or renal tumors were detected during the follow-up period. Treatment with propranolol was started for the multiple HH, according to international recommendations. At 3-, 6-, and 9-month follow up, a gradual decrease in the size of the hemangiomas and AFP levels was observed, without side effects. This is the fifth case in the literature combining HH and BWS, and among these, the third case with this specific genetic defect suggesting a possible association between HH and BWS caused by 11 paternal uniparental disomy [upd(11)pat]. The case also highlights that if treatment is warranted, then oral propranolol can be used for the management of infantile HH in BWS patients similarly to non-BWS patients.

Bowel Perforation in Vascular Ehlers-Danlos Syndrome: Case Report and Comprehensive Review

INTRODUCTION

Ehlers-Danlos syndromes (EDS) comprise a rare variety of genetic disorders, affecting all types of collagen. Herein, we describe a case of the vascular type of EDS, with coexisting segmental absence of intestinal musculature, while simultaneously performing a narrative review of the existing literature.

CASE PRESENTATION

A 23-year-old male patient with a history of multiple abdominal operations due to recurrent bowel perforations and the presence of a high-output enterocutaneous fistula was admitted to our surgical department for further evaluation and treatment. After detailed diagnostic testing, the diagnosis of vascular-type EDS (vEDS) was made and a conservative therapeutic approach was adopted. In addition, a comprehensive review of the international literature was carried out by applying the appropriate search terms.

RESULTS

The diagnosis of vEDS was molecularly confirmed by means of genetic testing. The patient was treated conservatively, with parenteral nutrition and supportive methods. Thirty-four cases of bowel perforation in vEDS have been reported so far. Interestingly, this case is the second one ever to report co-existence of vEDS with Segmental Absence of Intestinal Musculature.

CONCLUSIONS

Establishing the diagnosis of vEDS promptly is of vital significance in order to ensure that patients receive appropriate treatment. Due to initial non-specific clinical presentation, EDS should always be included in the differential diagnoses of young patients with unexplained perforations of the gastrointestinal tract.

Restrictive dermopathy due to ZMPSTE24 deficiency

Restrictive dermopathy (RD) (OMIM 275210) is a rare, lethal genodermatosis belonging to the group of laminopathies. It is caused by biallelic variants in ZMPSTE24 , which is involved in lamin A post-translational processing or, less frequently, by monoallelic variants in LMNA , leading to accumulation of truncated prelamin A protein (Navarro et al., 2004 ; Navarro et al., 2005 ). The main characteristics of RD include intrauterine growth retardation (IUGR), reduced fetal movement, premature rupture of membranes, translucent rigid skin, dysmorphic features and joint contractures. The prognosis is poor with all reported cases resulting in stillbirth or neonatal death (Navarro et al., 2014 ).

Herein we report a neonate born to healthy, non-consanguineous parents from Greece. The pregnancy was uneventful until the 32nd week, when a routine scan showed severe fetal growth restriction with normal Doppler flows. The female proband was born at 33 weeks of gestation by caesarean section, due to premature rupture of membranes, as well as anhydramnios, IUGR, fetal hypokinesia and distress. Her birth weight was 1.36 kg (5th centile, −1.6SD), length was 41 cm (14th centile) and head circumference was 29 cm (14th centile). Apgar score was 4 and 8 at the 1st and 5th minutes, respectively. She required immediate intubation and admission to the neonatal intensive care unit. She had a large fontanelle, short palpebral fissures, a small pinched nose, low-set dysplastic ears and an open, O-shaped mouth (Fig. 1 ). She had multiple joint contractures. Her skin was rigid and translucent and progressively developed erosions and scaling. She did not have eyebrows or eyelashes. She had severe lung hypoplasia and died of respiratory insufficiency on the 22nd day of life.

Expanding the phenotype of TAB2 variants and literature review

TAB2 is a gene located on chromosome 6q25.1 and plays a key role in development of the heart. Existing literature describes congenital heart disease as a common recognized phenotype of TAB2 gene variants, with evidence of a distinct syndromic phenotype also existing beyond this. Here we describe 14 newly identified individuals with nine novel, pathogenic TAB2 variants. The majority of individuals were identified through the Deciphering Developmental Disorders study through trio whole exome sequencing. Eight individuals had de novo variants, the other six individuals were found to have maternally inherited, or likely maternally inherited, variants. Five individuals from the same family were identified following cardiac disease gene panel in the proband and subsequent targeted familial gene sequencing. The clinical features of this cohort were compared to the existing literature. Common clinical features include distinctive facial features, growth abnormalities, joint hypermobility, hypotonia, and developmental delay. Newly identified features included feeding difficulties, sleep problems, visual problems, genitourinary abnormality, and other anatomical variations. Here we report 14 new individuals, including novel TAB2 variants, in order to expand the emerging syndromic clinical phenotype and provide further genotype-phenotype correlation.

Germline homozygous missense DEPDC5 variants cause severe refractory early-onset epilepsy, macrocephaly and bilateral polymicrogyria

DEPDC5 (DEP Domain-Containing Protein 5) encodes an inhibitory component of the mammalian target of rapamycin (mTOR) pathway and is commonly implicated in sporadic and familial focal epilepsies, both non-lesional and in association with focal cortical dysplasia. Germline pathogenic variants are typically heterozygous and inactivating. We describe a novel phenotype caused by germline biallelic missense variants in DEPDC5. Cases were identified clinically. Available records, including magnetic resonance imaging and electroencephalography, were reviewed. Genetic testing was performed by whole exome and whole-genome sequencing and cascade screening. In addition, immunohistochemistry was performed on skin biopsy. The phenotype was identified in nine children, eight of which are described in detail herein. Six of the children were of Irish Traveller, two of Tunisian and one of Lebanese origin. The Irish Traveller children shared the same DEPDC5 germline homozygous missense variant (p.Thr337Arg), whereas the Lebanese and Tunisian children shared a different germline homozygous variant (p.Arg806Cys). Consistent phenotypic features included extensive bilateral polymicrogyria, congenital macrocephaly and early-onset refractory epilepsy, in keeping with other mTOR-opathies. Eye and cardiac involvement and severe neutropenia were also observed in one or more patients. Five of the children died in infancy or childhood; the other four are currently aged between 5 months and 6 years. Skin biopsy immunohistochemistry was supportive of hyperactivation of the mTOR pathway. The clinical, histopathological and genetic evidence supports a causal role for the homozygous DEPDC5 variants, expanding our understanding of the biology of this gene.

Lethal COG6-CDG in neonatal patient with arachnodactyly, joint contractures, and skin manifestations: Founder mutation in the Southeastern European population?

Herein, we report a lethal case of the ultra-rare COG6-congenital disorder of glycosylation (CDG) presenting with skin manifestations (scaling and erosions) and joint contractures in a neonate of Albanian origin. The patient was homozygous for a COG6 pathogenic variant, previously reported in another three individuals of Greek, Bulgarian and Turkish descent. The presence of a founder mutation in the geographical area is possible. The index case emphasizes the need to consider CDGs in neonatal patients with skin manifestations and joint contractures, particularly patients of Southeastern European or West Asian origin.

Novel truncating mutations in CTNND1 cause a dominant craniofacial and cardiac syndrome

CTNND1 encodes the p120-catenin (p120) protein, which has a wide range of functions, including the maintenance of cell–cell junctions, regulation of the epithelial-mesenchymal transition and transcriptional signalling. Due to advances in next-generation sequencing, CTNND1 has been implicated in human diseases including cleft palate and blepharocheilodontic (BCD) syndrome albeit only recently. In this study, we identify eight novel protein-truncating variants, six de novo, in 13 participants from nine families presenting with craniofacial dysmorphisms including cleft palate and hypodontia, as well as congenital cardiac anomalies, limb dysmorphologies and neurodevelopmental disorders. Using conditional deletions in mice as well as CRISPR/Cas9 approaches to target CTNND1 in Xenopus, we identified a subset of phenotypes that can be linked to p120-catenin in epithelial integrity and turnover, and additional phenotypes that suggest mesenchymal roles of CTNND1. We propose that CTNND1 variants have a wider developmental role than previously described and that variations in this gene underlie not only cleft palate and BCD but may be expanded to a broader velocardiofacial-like syndrome.

Novel Hemizygous Missense Variant of Spermine Synthase (SMS) Gene Causes Snyder-Robinson Syndrome in a Four-Year-Old Boy

Snyder-Robinson syndrome (SRS) is an extremely rare X-linked intellectual disability syndrome (MRXSSR; MIM #309583). The main clinical features of SRS include psychomotor delay, hypotonia, and asthenic-type body habitus - reduced body weight and bone abnormalities (osteoporosis, fractures, kyphoscoliosis). We report a case of SRS with a hemizygous missense variant in the SMS gene,c.334C>G (p.Pro112Ala), in a 4-year-old boy, who initially developed hypotonia, delayed motor skills, and subsequently epilepsy. This variant in SMS was found to be de novo. To the best of our knowledge, this novel SMS gene variant has never been previously reported in disease-related variation databases, such as ClinVar or HGMD.

Bi-allelic Variants in the GPI Transamidase Subunit PIGK Cause a Neurodevelopmental Syndrome with Hypotonia, Cerebellar Atrophy, and Epilepsy

Glycosylphosphatidylinositol (GPI)-anchored proteins are critical for embryogenesis, neurogenesis, and cell signaling. Variants in several genes participating in GPI biosynthesis and processing lead to decreased cell surface presence of GPI-anchored proteins (GPI-APs) and cause inherited GPI deficiency disorders (IGDs). In this report, we describe 12 individuals from nine unrelated families with 10 different bi-allelic PIGK variants. PIGK encodes a component of the GPI transamidase complex, which attaches the GPI anchor to proteins. Clinical features found in most individuals include global developmental delay and/or intellectual disability, hypotonia, cerebellar ataxia, cerebellar atrophy, and facial dysmorphisms. The majority of the individuals have epilepsy. Two individuals have slightly decreased levels of serum alkaline phosphatase, while eight do not. Flow cytometric analysis of blood and fibroblasts from affected individuals showed decreased cell surface presence of GPI-APs. The overexpression of wild-type (WT) PIGK in fibroblasts rescued the levels of cell surface GPI-APs. In a knockout cell line, transfection with WT PIGK also rescued the GPI-AP levels, but transfection with the two tested mutant variants did not. Our study not only expands the clinical and known genetic spectrum of IGDs, but it also expands the genetic differential diagnosis for cerebellar atrophy. Given the fact that cerebellar atrophy is seen in other IGDs, flow cytometry for GPI-APs should be considered in the work-ups of individuals presenting this feature.

KIF1A-related disorders in children: A wide spectrum of central and peripheral nervous system involvement

KIF1A-related disorders (KRD) were first described in 2011 and the phenotypic spectrum has subsequently expanded to encompass a range of central and peripheral nervous system involvement. Here we present a case series demonstrating the range of clinical, neurophysiological, and radiological features which may occur in childhood-onset KRD. We report on all the children and young people seen at a single large tertiary centre. Data were collected through a retrospective case-notes review. Twelve individuals from 10 families were identified. Eight different mutations were present, including four novel mutations. Two patients displayed a very severe phenotype including congenital contractures, severe spasticity and/or dystonia, dysautonomia, severe sensorimotor polyneuropathy and optic atrophy, significant white matter changes on brain MRI, respiratory insufficiency, and complete lack of neurodevelopmental progress. The remaining 10 patients represented a spectrum of severity with common features including a movement disorder with spasticity and/or dystonia, subtle features of dysautonomia, sensory axonal neuropathy, varying degrees of optic atrophy and of learning and/or behavioural difficulties, and subtle or absent-but sometimes progressive-changes in white matter on MRI. Epilepsy was common among the more severely affected children. This case series demonstrates that KRD comprise a range of neurological disorders, with both the milder and the more severe forms combining central and peripheral (including autonomic) nervous system deficits.

Phenotypic spectrum associated with de novo mutations in QRICH1 gene

Rare de novo mutations represent a significant cause of idiopathic developmental delay (DD). The use of next-generation sequencing (NGS) has boosted the identification of de novo mutations in an increasing number of novel genes. Here we present 3 unrelated children with de novo loss-of-function (LoF) mutations in QRICH1, diagnosed through trio-based exome sequencing. QRICH1 encodes the glutamine-rich protein 1, which contains 1 caspase activation recruitment domain and is likely to be involved in apoptosis and inflammation. All 3 children had speech delay, learning difficulties, a prominent nose and a thin upper lip. In addition, 2 of them had mildly raised creatine kinase (CK) and 1 of them had autism. Despite their small number, the patients had a relatively consistent pattern of clinical features suggesting the presence of a QRICH1-associated phenotype. LoF mutations in QRICH1 are suggested as a novel cause of DD.

Angelman Syndrome due to a Maternally Inherited Intragenic Deletion Encompassing Exons 7 and 8 of the UBE3A Gene

Angelman syndrome (AS) is characterised by developmental delay, lack of speech, seizures, a characteristic behavioural profile with a happy demeanour, microcephaly, and ataxia. More than two-thirds of cases are due to an approximately 5-Mb interstitial deletion of the imprinted region 15q11.2q13, which is usually de novo. The rest are associated with point mutations in the UBE3A gene, imprinting defects, and paternal uniparental disomy. Small intragenic UBE3A deletions have rarely been described. They are usually maternally inherited, increasing the recurrence risk to 50%, and may be missed by conventional testing (methylation studies and UBE3A gene sequencing). We describe a boy with AS due to an 11.7-kb intragenic deletion. The deletion was identified by array-CGH and was subsequently detected in his affected first cousin and unaffected maternal grandfather, mother, and aunt, confirming the silencing of the paternal allele. The patient had developmental delay, speech impairment, a happy demeanour, microcephaly, and an abnormal EEG, but no seizures by the age of 4 years. Delineation of the underlying genetic mechanism is of utmost importance for reasons of genetic counselling, as well as appropriate management and prognosis. Alternative techniques, such as array-CGH and MLPA, are necessary when conventional testing for AS has failed to identify the underlying genetic mechanism.

Severe clinical presentation in monozygotic twins with 10p15.3 microdeletion syndrome

Submicroscopic deletion of 10p15.3 is a rare genetic disorder, currently reported in 21 unrelated patients. It is mainly associated with cognitive deficits, speech disorders, motor delay and hypotonia. The size of the deleted region ranges between 0.15 and 4 Mb and does not generally correlate with phenotype. A monozygotic female twin pair with a de novo 2.7 Mb deletion of 10p15.3 is herein reported. The girls presented at the age of 8 months with severe developmental delay and failure to thrive since the first month of life. Their perinatal and family history was unremarkable. On admission they both exhibited generalized dystonia, microcephaly, complete absence of voluntary movements and visual/auditory unresponsiveness. Their brain MRIs demonstrated dilatation of ventricles, subarachnoid spaces and anterior interhemispheric fissure and sylvian fissures bilaterally. Cranial radiography revealed partial fusion of both coronal sutures. Visual and brainstem auditory evoked potentials were markedly abnormal, indicating severe visual and sensorineural hearing impairment. The electroencephalogram, as well as a screening for inborn errors of metabolism, were unremarkable. Both patients required gastrostomy and tracheostomy before the age of 1 year. They were, additionally, managed with physical therapy, as well as baclofen and low-dose haloperidol. Their current state at the age of 2 years is relatively stable. The index patients' phenotype includes features, such as dystonic cerebral palsy, visual and sensorineural hearing impairment or craniosynostosis, which have not been previously reported in individuals with 10p15.3 deletion. It is necessary to consider these novel clinical features and investigate their possible relationship with the recently recognized syndrome.

Autism spectrum disorders: the quest for genetic syndromes

Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disabilities with various etiologies, but with a heritability estimate of more than 90%. Although the strong correlation between autism and genetic factors has been long established, the exact genetic background of ASD remains unclear. A number of genetic syndromes manifest ASD at higher than expected frequencies compared to the general population. These syndromes account for more than 10% of all ASD cases and include tuberous sclerosis, fragile X, Down, neurofibromatosis, Angelman, Prader-Willi, Williams, Duchenne, etc. Clinicians are increasingly required to recognize genetic disorders in individuals with ASD, in terms of providing proper care and prognosis to the patient, as well as genetic counseling to the family. Vice versa, it is equally essential to identify ASD in patients with genetic syndromes, in order to ensure correct management and appropriate educational placement. During investigation of genetic syndromes, a number of issues emerge: impact of intellectual disability in ASD diagnoses, identification of autistic subphenotypes and differences from idiopathic autism, validity of assessment tools designed for idiopathic autism, possible mechanisms for the association with ASD, etc. Findings from the study of genetic syndromes are incorporated into the ongoing research on autism etiology and pathogenesis; different syndromes converge upon common biological backgrounds (such as disrupted molecular pathways and brain circuitries), which probably account for their comorbidity with autism. This review paper critically examines the prevalence and characteristics of the main genetic syndromes, as well as the possible mechanisms for their association with ASD.

Pontocerebellar hypoplasia in extreme prematurity: clinical and neuroimaging findings

The involvement of the cerebellum in unfavorable outcomes of extreme prematurity is increasingly recognized. Evidence implicates both cerebellar injury and cerebellar growth failure, which, along with supratentorial lesions, aggravate motor and developmental outcomes. We describe clinical and neuroradiologic findings of 12 extremely premature patients with acquired pontocerebellar hypoplasia (mean follow-up, 4 years). Patients' neuromotor outcomes involved combined motor abnormalities (spasticity, dystonia, and ataxia), whereas 25% were ambulatory by age 4 years. All patients exhibited developmental delays of variable degrees. One patient died at age 7.5 years. The possible etiopathogenesis, presentations, sequelae, and differential diagnoses of acquired pontocerebellar hypoplasia are discussed.

Recurrent episodes of rhabdomyolysis in pontocerebellar hypoplasia type 2

Pontocerebellar hypoplasia type 2 is an autosomal recessive disorder characterized by hypoplasia and atrophy of the cerebellum and pons, leading to microcephaly, dystonia/dyskinesia, seizures, and severe cognitive impairment. Until lately it was considered a CNS-refined disease, but recent reports have associated it with muscular defects, as well. A 5-year-old boy with genetically confirmed pontocerebellar hypoplasia type 2 is described. The patient had all the clinical and radiological features of the disease, but he, additionally, exhibited two episodes of rhabdomyolysis precipitated by respiratory infections. The possible mechanisms associating encephalopathy and myopathy in pontocerebellar hypoplasia type 2 are discussed.

Life-threatening hyponatremia and acute renal failure due to iatrogenic neonatal bladder rupture

Neonatal urinary ascites is a rare entity, usually associated with a spontaneous rupture of the bladder with an underlying pathology such as high pressure or wall disruption. Its presentation involves abdominal distension, metabolic derangement and respiratory compromise. We report the case of a male neonate with solitary functioning kidney presented with life-threatening persistent hyponatremia and acute renal failure due to iatrogenic bladder rupture after catheterization. The aim of our report is to raise awareness on the possibility of bladder perforation in neonates even in the absence of technical faults. We discuss the uncommon presentation of our case and highlight the need for early recognition and management of urinary ascites, addressing all subspecialties involved in diagnostic or therapeutic procedures of neonates with urinary abnormalities.

Childhood autism and auditory system abnormalities

Hearing disorders are common among children with autism, ranging from peripheral and sensorineural hearing deficit or loss to auditory hypersensitivity with bizarre reactions to sounds. The auditory abnormalities and consequent sensory deprivation exacerbate the communication deficit of autism, and early auditory assessment holds an important place in the planning of intervention and the overall prognosis of patients. Physiologic, pathologic, imaging, and neurochemical studies have revealed an array of aberrations in the perception and processing of the audiologic stimuli, including (among others) maturational defects, atypical lateralization, and serotonin dysfunction.

The serotonergic system: its role in pathogenesis and early developmental treatment of autism

Autism is a severe childhood disorder already presenting in the first 3 years of life and, therefore, strongly correlated with neurodevelopmental alterations in prenatal, as well as postnatal period. Neurotransmitters hold a pivotal role in development by providing the stimulation needed for synapses and neuronal networks to be formed during the critical period of neuroplasticity. Aberrations of the serotonergic system modify key processes in the developing brain and are strongly implicated in the pathophysiology of developmental disorders. Evidence for the role of serotonin in autism emerges from neuropathological, imaging and genetic studies. Due to its developmental arrest, autism requires early intervention that would, among others, target the disrupted serotonergic system and utilize brain plasticity to elicit clinically important brain changes in children.

Tyrosine hydroxylase deficiency with severe clinical course

Tyrosine hydroxylase (TH) deficiency is a rare autosomal recessive disorder mapped to chromosome 11p15.5. Its clinical expression varies with presentations as dopa-responsive dystonia (recessive Segawa's disease), dopa-responsive infantile parkinsonism, dopa-responsive spastic paraplegia, progressive infantile encephalopathy or dopa-non-responsive dystonia. We describe a 7-year-old boy with progressive infantile encephalopathy and non-responsiveness to dopamine. The patient demonstrated generalized hypotonia, pyramidal tract dysfunction and temperature instability after the second month of life. Dystonia, tremor and oculogyric crises complicated the clinical picture during the following months. Neurotransmitter analysis in CSF disclosed almost undetectable levels of HVA and MHPG, whereas serum prolactin was profoundly increased. Subsequent molecular analysis revealed homozygosity for a missense mutation (c.707T>C) in the TH gene. l-Dopa therapy in both high and low doses resulted in massive hyperkinesias, while substitution with selegiline exerted only a mild beneficial effect. Today, at the age of 7 years, the patient demonstrates severe developmental retardation with marked trunkal hypotonia, hypokinesia and occasionally dystonic and/or hyperkinetic crises. He is the third Greek patient with TH deficiency to be reported. Since all three patients carry the same pathogenetic mutation, a founder effect is suspected.

MR spectroscopy and serial magnetic resonance imaging in a patient with mitochondrial cystic leukoencephalopathy due to complex I deficiency and NDUFV1 mutations and mild clinical course

We present clinical, magnetic resonance imaging and MR spectroscopic findings of a female patient, first admitted at the age of 9 months for regression of motor milestones and signs of mild spastic diplegia. Magnetic resonance imaging (MRI) demonstrated periventricular white matter abnormalities with sparing of the subcortical white matter. Subsequent MRIs, performed at the ages of 13 and 16 months, demonstrated progression of the white matter changes, progressive white matter rarefaction and cystic degeneration, and additional involvement of the corpus callosum; only the subcortical white matter remained spared. Proton MR spectroscopy revealed lactate elevation in the white matter. Blood lactate and lactate/pyruvate ratio were mildly elevated. Subsequent analysis of mitochondrial function in muscle tissue showed decreases in substrate oxidation and in ATP and CrP production rates. Complex I activity was seriously decreased, whereas mild decreases of complex II and IV activities were also noted. Analysis of the NDUFV1 gene revealed compound heterozygosity for two point mutations, each of them carried by one parent. The further clinical course of the patient was uphill; she slowly regained all previously lost motor milestones. In conclusion, diffuse white matter changes on MRI are compatible with mitochondrial encephalopathy and not necessarily associated with a severe clinical course.

L-2-Hydroxyglutaric aciduria presenting with severe autistic features

L-2-Hydroxyglutaric aciduria (L-2-HGA) is an autosomal recessive neurometabolic disorder characterized by psychomotor delay, ataxia, macrocephaly and typical neuroradiological findings of subcortical leucoencephalopathy. Recently, the disease causing gene has been discovered (L2HGDH) encoding L-2-hydroxyglutarate dehydrogenase. We present a 3-year-old boy with L-2-HGA, who demonstrated macrocephaly, noted already in utero with ultrasound. Cranial MRI demonstrated diffuse subcortical encephalopathy with increased signal of the subcortical white matter. Subsequent metabolic screening revealed increased levels of L-2-HGA, and genomic DNA analysis demonstrated two missense mutations in L-2-HGDG. Patient's further motor development was mildly impaired, whilst his speech development was profoundly impaired (first words at the age of 2 years). Since the age of 2 years he started demonstrating autistic repetitive behaviors and movements, increasing aloofness to his environment and limitations in the variety of spontaneous activity (CARS score: 44/60-severe autism). Autism has not so far been described in L-2-HGA and may be considered as an additional feature of the phenotypic spectrum.