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Purpose: Pathogenic variants of FIG4 generate enlarged lysosomes and neurological and developmental disorders. To identify additional genes regulating lysosomal volume, we carried out a genome-wide activation screen to detect suppression of enlarged lysosomes in FIG4 -/- cells., Methods: The CRISPR-a gene activation screen utilized sgRNAs from the promoters of protein-coding genes. Fluorescence-activated cell sorting separated cells with correction of the enlarged lysosomes from uncorrected cells. Patient variants of SLC12A9 were identified by exome or genome sequencing and studied by segregation analysis and clinical characterization., Results: Overexpression of SLC12A9, a solute co-transporter, corrected lysosomal swelling in FIG4 -/- cells. SLC12A9 (NP_064631.2) colocalized with LAMP2 at the lysosome membrane. Biallelic variants of SLC12A9 were identified in 3 unrelated probands with neurodevelopmental disorders. Common features included intellectual disability, skeletal and brain structural abnormalities, congenital heart defects, and hypopigmented hair. Patient 1 was homozygous for nonsense variant p.(Arg615∗), patient 2 was compound heterozygous for p.(Ser109Lysfs∗20) and a large deletion, and proband 3 was compound heterozygous for p.(Glu290Glyfs∗36) and p.(Asn552Lys). Fibroblasts from proband 1 contained enlarged lysosomes that were corrected by wild-type SLC12A9 cDNA. Patient variant p.(Asn552Lys) failed to correct the lysosomal defect., Conclusion: Impaired function of SLC12A9 results in enlarged lysosomes and a recessive disorder with a recognizable neurodevelopmental phenotype., Competing Interests: Conflict of Interest The authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: We established the genetic etiology of a syndromic neurodevelopmental condition characterized by variable cognitive impairment, recognizable facial dysmorphism, and a constellation of extra-neurological manifestations., Methods: We performed phenotypic characterization of 6 participants from 4 unrelated families presenting with a neurodevelopmental syndrome and used exome sequencing to investigate the underlying genetic cause. To probe relevance to the neurodevelopmental phenotype and craniofacial dysmorphism, we established two- and three-dimensional human stem cell-derived neural models and generated a stable cachd1 zebrafish mutant on a transgenic cartilage reporter line., Results: Affected individuals showed mild cognitive impairment, dysmorphism featuring oculo-auriculo abnormalities, and developmental defects involving genitourinary and digestive tracts. Exome sequencing revealed biallelic putative loss-of-function variants in CACHD1 segregating with disease in all pedigrees. RNA sequencing in CACHD1-depleted neural progenitors revealed abnormal expression of genes with key roles in Wnt signaling, neurodevelopment, and organ morphogenesis. CACHD1 depletion in neural progenitors resulted in reduced percentages of post-mitotic neurons and enlargement of 3D neurospheres. Homozygous cachd1 mutant larvae showed mandibular patterning defects mimicking human facial dysmorphism., Conclusion: Our findings support the role of loss-of-function variants in CACHD1 as the cause of a rare neurodevelopmental syndrome with facial dysmorphism and multisystem abnormalities., Competing Interests: Conflict of Interest The authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: RNF213, encoding a giant E3 ubiquitin ligase, has been recognized for its role as a key susceptibility gene for moyamoya disease. Case reports have also implicated specific variants in RNF213 with an early-onset form of moyamoya disease with full penetrance. We aimed to expand the phenotypic spectrum of monogenic RNF213-related disease and to evaluate genotype-phenotype correlations., Methods: Patients were identified through reanalysis of exome sequencing data of an unselected cohort of unsolved pediatric cases and through GeneMatcher or ClinVar. Functional characterization was done by proteomics analysis and oxidative phosphorylation enzyme activities using patient-derived fibroblasts., Results: We identified 14 individuals from 13 unrelated families with (de novo) missense variants in RNF213 clustering within or around the Really Interesting New Gene (RING) domain. Individuals presented either with early-onset stroke (n = 11) or with Leigh syndrome (n = 3). No genotype-phenotype correlation could be established. Proteomics using patient-derived fibroblasts revealed no significant differences between clinical subgroups. 3D modeling revealed a clustering of missense variants in the tertiary structure of RNF213 potentially affecting zinc-binding suggesting a gain-of-function or dominant negative effect., Conclusion: De novo missense variants in RNF213 clustering in the E3 RING or other regions affecting zinc-binding lead to an early-onset syndrome characterized by stroke or Leigh syndrome., Competing Interests: Conflict of Interest A.S. is supported by the BONFOR program of the Medical Faculty, University of Bonn (O-149.0134). All other authors declare no conflicts of interest., (Copyright © 2023 American College of Medical Genetics and Genomics. Published by Elsevier Inc. All rights reserved.)

Purpose: Coffin-Siris and Nicolaides-Baraitser syndromes are recognizable neurodevelopmental disorders caused by germline variants in BAF complex subunits. The SMARCC2 BAFopathy was recently reported. Herein, we present clinical and molecular data on a large cohort., Methods: Clinical symptoms for 41 novel and 24 previously published affected individuals were analyzed using the Human Phenotype Ontology. For genotype-phenotype correlations, molecular data were standardized and grouped into non-truncating and likely gene-disrupting (LGD) variants. Missense variant protein expression and BAF-subunit interactions were examined using 3D protein modeling, co-immunoprecipitation, and proximity-ligation assays., Results: Neurodevelopmental delay with intellectual disability, muscular hypotonia, and behavioral disorders were the major manifestations. Clinical hallmarks of BAFopathies were rare. Clinical presentation differed significantly, with LGD variants being predominantly inherited and associated with mildly reduced or normal cognitive development, whereas non-truncating variants were mostly de novo and presented with severe developmental delay. These distinct manifestations and non-truncating variant clustering in functional domains suggest different pathomechanisms. In vitro testing showed decreased protein expression for N-terminal missense variants similar to LGD., Conclusion: This study improved SMARCC2 variant classification and identified discernible SMARCC2-associated phenotypes for LGD and non-truncating variants, which were distinct from other BAFopathies. The pathomechanism of most non-truncating variants has yet to be investigated., Competing Interests: Conflict of Interest Renee Bend and Julie Rath are employees of PreventionGenetics, part of Exact Sciences. Michelle M. Morrow and Francisca Millan are employees of GeneDx, LLC. All other authors declare no conflicts of interests., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Aromatic l-amino acid decarboxylase (AADC) deficiency is a rare autosomal recessive neurometabolic disorder caused by biallelic pathogenic variants in the DDC gene and mainly characterized by developmental delay, hypotonia, and oculogyric crises. Early diagnosis is crucial for correct patient management; however, many patients remain misdiagnosed or undiagnosed due to the rarity and clinical heterogeneity of the disorder especially in the milder forms. Here, we applied exome sequencing approach by screening 2000 paediatric patients with neurodevelopmental disorders to identify possible new AADC variants and AADC deficiency patients. We identified five distinct DDC variants in two unrelated individuals. Patient #1 harboured two compound heterozygous DDC variants: c.436-12T > C and c.435 + 24A>C and presented with psychomotor delay, tonic spasms, and hyperreactivity. Patient #2 had three homozygous AADC variants: c.1385G > A; p.Arg462Gln, c.234C > T; p.Ala78 = , and c.201 + 37A > G and presented with developmental delay and myoclonic seizures. The variants were classified as benign class I variants and therefore non-causative according to the ACMG/AMP guidelines. Since the AADC protein is a structural and functional obligate homodimer, we evaluated the possible AADC polypeptide chain combinations in the two patients and determined the effects resulting from the amino acid substitution Arg462Gln. Our patients carrying DDC variants presented clinical manifestations not precisely overlapped to the classical symptoms exhibited by the most severe AADC deficiency cases. However, screening data derived from exome sequencing in patients featuring wide-range symptoms related to neurodevelopmental disorders may help to identify AADC deficiency patients, especially when applied to larger cohorts., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Pasquale Striano reports a relationship with PTC Therapeutics International Ltd that includes: consulting or advisory. Mariarita Bertoldi reports a relationship with PTC Therapeutics International Ltd that includes: consulting or advisory., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Purpose: Protein arginine methyltransferase 7 (PRMT7) is a member of a family of enzymes that catalyzes the methylation of arginine residues on several protein substrates. Biallelic pathogenic PRMT7 variants have previously been associated with a syndromic neurodevelopmental disorder characterized by short stature, brachydactyly, intellectual developmental disability, and seizures. To our knowledge, no comprehensive study describes the detailed clinical characteristics of this syndrome. Thus, we aim to delineate the phenotypic spectrum of PRMT7-related disorder., Methods: We assembled a cohort of 51 affected individuals from 39 different families, gathering clinical information from 36 newly described affected individuals and reviewing data of 15 individuals from the literature., Results: The main clinical characteristics of the PRMT7-related syndrome are short stature, mild to severe developmental delay/intellectual disability, hypotonia, brachydactyly, and distinct facial morphology, including bifrontal narrowing, prominent supraorbital ridges, sparse eyebrows, short nose with full/broad nasal tip, thin upper lip, full and everted lower lip, and a prominent or squared-off jaw. Additional variable findings include seizures, obesity, nonspecific magnetic resonance imaging abnormalities, eye abnormalities (i.e., strabismus or nystagmus), and hearing loss., Conclusion: This study further delineates and expands the molecular, phenotypic spectrum and natural history of PRMT7-related syndrome characterized by a neurodevelopmental disorder with skeletal, growth, and endocrine abnormalities., Competing Interests: Conflict of Interest Megan Li is an employee of Invitae. Erin Torti, Amber Begtrup, and Rhonda E Schnur are employees of GeneDx, Inc. All other authors declare no conflicts of interest., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: EEG anomalies and epilepsy are a not so rare clinical manifestation in patients with Phosphatase and tensin homolog (PTEN) variants. The main aim of this study is to analyze the characteristics of EEG traces, neuroimaging findings and epilepsy to better define the neurological aspects in a set of patients with PTEN variants collected in four Italian Centres. As a secondary aim, we describe the neurodevelopmental profile and the psychiatric comorbidities of this cohort., Methods: Patients with PTEN variants, identified by Sanger sequencing or target resequencing, were enrolled. For each subjects, clinical data were retrospectively extracted from medical charts, with a focus on epilepsy and neuroimaging data., Results: 54 patients with PTEN variants were enrolled, with a mean age of 18.8 years. 72.2% have at least one psychiatric diagnosis, being Autism Spectrum Disorder and Intellectual Disability the most frequent diagnosis (29 and 25 cases, respectively). 22 subjects show an abnormal EEG and 8 received a diagnosis of epilepsy, mainly focal epilepsy (7/8), with a mean age at seizure onset of 3.8 years. 3/8 subjects have a drug resistant epilepsy, independently from the underlying neuroimaging pattern. The finding of a Focal cortical dysplasia is significantly associated with both an abnormal EEG (p = 0.02) and the occurrence of seizures (p = 0.002)., Conclusion: EEG should be taken into consideration in the first-line diagnostic flowchart of subjects with PTEN variants. The onset of a focal epilepsy, independently from its response to antiepileptic drugs, highly recommends to carry out a neuroimaging exam., (Copyright © 2022 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Background: Heterozygous POLR2A variants have been recently reported in patients with a neurodevelopmental syndrome characterized by profound infantile-onset hypotonia. POLR2A encodes the highly conserved RBP1 protein, an essential subunit of the DNA-dependent RNA polymerase II., Case Presentation: We investigated a 12-year-old girl presenting with an early-onset encephalopathy characterized by psychomotor delay, facial dysmorphism, refractory epilepsy with variable seizure types, behavioural abnormalities, and sleep disorder. Brain MRI showed a slowly progressive cerebellar atrophy. Trio-exome sequencing (Trio-ES) revealed the de novo germline variant NM_000937.5:c.1370T>C; p.(Ile457Thr) in POLR2A. This variant was previously reported in a subject with profound generalized hypotonia and muscular atrophy by Haijes et al. Our patient displayed instead a severe epileptic phenotype with refractory hypotonic seizures with impaired consciousness, myoclonic jerks, and drop attacks., Conclusion: This case expands the clinical spectrum of POLR2A-related syndrome, highlighting its phenotypic variability and supporting the relevance of epilepsy as a core feature of this emerging condition., (Copyright © 2022 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

Objectives: To assess the impact of the COVID-19 pandemic on rates of hospital visitation and rates and durations of developmental care practices for infants born preterm., Methods: We analyzed electronic medical record data from 129 infants born at less than 32 weeks gestational age (GA) cared for in the Lucile Packard Children's Hospital neonatal intensive care unit (NICU) in a COVID-19-affected period (March 8, 2020 to Nov 30, 2020, n = 67) and the analogous period in 2019 (n = 62). Rates of family visitation and of family- and clinical staff-delivered developmental care were compared across cohorts, adjusting for covariates., Results: Families of infants visited the hospital at nearly half of the rate during 2020 as during 2019 (p = 0.001). Infants experienced developmental care less frequently in 2020 vs. 2019 (3.0 vs. 4.3 activities per day; p = 0.001), resulting in fewer minutes per day (77.5 vs. 130.0; p = 0.001). In 2020, developmental care activities were 5 min shorter, on average, than in 2019, p = 0.001. Similar reductions occurred in both family- and staff-delivered developmental care. Follow-up analyses indicated that effects persisted and even worsened as the pandemic continued through fall 2020, despite relaxation of hospital visitation policies., Conclusions: The COVID-19 pandemic has negatively impacted family visitation and preterm infant developmental care practices in the NICU, both experiences associated with positive health benefits. Hospitals should create programs to improve family visitation and engagement, while also increasing staff-delivered developmental care. Careful attention should be paid to long-term follow up of preterm infants and families., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Lafora disease (LD) is characterized by progressive myoclonus, refractory epilepsy, and cognitive deterioration. This complex neurodegenerative condition is caused by pathogenic variants in EPM2A/EPM2B genes, encoding two essential glycogen metabolism enzymes known as laforin and malin. Long-term follow-up data are lacking. We describe the clinical features and genetic findings of a cohort of 26 Italian patients with a long clinical follow-up., Methods: Patients with EPM2A/EPM2B pathogenic variants were identified by direct gene sequencing or gene panels with targeted re-sequencing. Disease progression, motor functions, and mental performance were assessed by a simplified disability scale. Spontaneous/action myoclonus severity was scored by the Magaudda Scale., Results: Age range was 12.2-46.2 years (mean:25.53 ± 9.14). Age at disease onset ranged from 10 to 22 years (mean:14.04 ± 2.62). The mean follow-up period was 11.48 ± 7.8 years. Twelve out of the 26 (46%) patients preserved walking ability and 13 (50%) maintained speech. A slower disease progression with preserved ambulation and speech after ≥4 years of follow-up was observed in 1 (11%) out of the 9 (35%) EPM2A patients and in 6 (35%) out of the 17 (65%) EPM2B patients. Follow-up was >10 years in 7 (41.2%) EPM2B individuals, including two harbouring the homozygous p.(D146N) pathogenic variant., Conclusions: This study supports an overall worse disease outcome with severe deterioration of ambulation and speech in patients carrying EPM2A mutations. However, the delayed onset of disabling symptoms observed in the EPM2B subjects harbouring the p.(D146N) pathogenic variant suggests that the underlying causative variant may still influence LD severity., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Purpose: Epilepsy is a main manifestation in the autosomal dominant mental retardation syndrome caused by heterozygous variants in MEF2C. We aimed to delineate the electro-clinical features and refine the genotype-phenotype correlations in patients with MEF2C haploinsufficiency., Methods: We thoroughly investigated 25 patients with genetically confirmed MEF2C-syndrome across 12 different European Genetics and Epilepsy Centers, focusing on the epileptic phenotype. Clinical features (seizure types, onset, evolution, and response to therapy), EEG recordings during waking/sleep, and neuroimaging findings were analyzed. We also performed a detailed literature review using the terms "MEF2C", "seizures", and "epilepsy"., Results: Epilepsy was diagnosed in 19 out of 25 (~80%) subjects, with age at onset <30 months. Ten individuals (40%) presented with febrile seizures and myoclonic seizures occurred in ~50% of patients. Epileptiform abnormalities were observed in 20/25 patients (80%) and hypoplasia/partial agenesis of the corpus callosum was detected in 12/25 patients (~50%). Nine patients harbored a 5q14.3 deletion encompassing MEF2C and at least one other gene. In 7 out of 10 patients with myoclonic seizures, MIR9-2 and LINC00461 were also deleted, whereas ADGRV1 was involved in 3/4 patients with spasms., Conclusion: The epileptic phenotype of MEF2C-syndrome is variable. Febrile and myoclonic seizures are the most frequent, usually associated with a slowing of the background activity and irregular diffuse discharges of frontally dominant, symmetric or asymmetric, slow theta waves with interposed spike-and-waves complexes. The haploinsufficiency of ADGRV1, MIR9-2, and LINC00461 likely contributes to myoclonic seizures and spasms in patients with MEF2C syndrome., (Copyright © 2021. Published by Elsevier Ltd.)

Premature and medically vulnerable infants experience early and sometimes prolonged separation from their parents, intrusive and unnatural environments, painful and distressing procedures, difficulties with physiological regulation, increased biological and neurological vulnerabilities, and grow up to have higher rates of neurocognitive and psychosocial difficulties. Parents of infants born prematurely or with medical vulnerabilities, in turn, experience significant distress and are a psychiatrically vulnerable population, with very high rates of depression, anxiety, and posttraumatic stress disorder. The combination of these factors cause significant challenges for some of these infants and parents in developing an early optimal relationship and connection. Given the critical importance of early relationships with main caregivers for infant mental health and long-term developmental outcomes, we review various targets of intervention to promote healthy infant and parent mental health and bonding thereby facilitating an optimal infant-parent relationship in the NICU population., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Neuronal ceroid lipofuscinosis (NCL) is a hereditary lysosomal storage disease with progressive brain neurodegeneration. Mutations in ceroid lipofuscinosis neuronal protein 5 (CLN5) cause CLN5 disease, a severe condition characterized by seizures, visual failure, motor decline, and progressive cognitive deterioration. This study aimed to identify causative gene variants in Pakistani consanguineous families diagnosed with NCL., Methods: After a thorough clinical and neuroradiological characterization, whole exome sequencing (WES) was performed in 3 patients from 2 unrelated families. Segregation analysis was subsequently performed through Sanger sequencing ANALYSIS: WES led to the identification of the 2 novel homozygous variants c.925&#95;926del, (p.Leu309AlafsTer4) and c.477 T > C, (p.Cys159Arg)., Conclusion: In this study, we report two novel CLN5 cases in the Punjab region of Pakistan. Our observations will help clinicians observe and compare common and unique clinical features of NCL patients, further improving our current understanding of NCL., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Over the last decades, significant advancements have been achieved in the treatment of pediatric brain tumors as a result of radiation therapy (RT). With the increasing diffusion of this treatment, iatrogenic damage to cerebrovascular tissues contouring the radiation target volume has become the subject of debate, especially radiation-induced moyamoya syndrome (RIMS)., Methods: A systematic literature search was performed on the association between moyamoya vasculopathy and cranial irradiation in children. Large case series of patients with moyamoya were analyzed and clinicoradiologic data were collected reviewing pediatric patients treated with RT for primary brain tumors at our institution., Results: The risk of developing RIMS is higher in younger children, in patients with optic pathway glioma, and in those receiving higher radiation doses. Headache is the most common presenting symptom and cerebral infarction is frequent. The preferred surgical techniques were pial synangiosis and encephaloduroarteriosynangiosis. In our case series, surgical revascularization led to neovascularization, with clinical improvement or stability in all patients. Medical therapy did not significantly affect the clinical course., Conclusions: Pediatric patients receiving involved field RT for the treatment of brain tumors have an increased risk of developing RIMS. Prompt diagnosis and early surgical revascularization play a pivotal role in decreasing the clinical impact of this complication. The use of new techniques, such as the intensity-modulated RT, and the increasing dose saving for the organs at risk, are essential to prevent iatrogenic vasculopathy. The combination of appropriate medical therapy and surgery will improve patient management and clinical outcome., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Magnesium (Mg 2+ ) plays a crucial role in many biological processes especially in the brain, heart and skeletal muscle. Mg 2+ homeostasis is regulated by intestinal absorption and renal reabsorption, involving a combination of different epithelial transport pathways. Mutations in any of these transporters result in hypomagnesemia with variable clinical presentations. Among these, CNNM2 is found along the basolateral membrane of distal tubular segments where it is involved in Mg 2+ reabsorption. To date, heterozygous mutations in CNNM2 have been associated with a variable phenotype, ranging from isolated hypomagnesemia to intellectual disability and epilepsy. The only homozygous mutation reported so far, is responsible for hypomagnesemia associated with a severe neurological phenotype characterized by refractory epilepsy, microcephaly, severe global developmental delay and intellectual disability. Here, we report the second homozygous CNNM2 mutation (c.1642G > A,p.Val548Met) in a Moroccan patient, presenting with hypomagnesemia and severe epileptic encephalopathy. Thus, we review and discuss the phenotypic spectrum associated with CNNM2 mutations., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Background: Proton therapy has proven to be effective and safe in the treatment of radioresistant skull base tumors such as chordomas. Thanks to the peculiar physical properties of the proton beam, radiation energy is delivered in a narrow space called the Bragg peak and the surrounding normal tissues receive a minimal amount of the radiation dose. This is important to lower the risk of radiation-induced damage, especially in children. However, local adverse effects in proximity to the target volume may occur. In particular, the development of moyamoya syndrome (MMS) has been rarely reported in children receiving proton beam therapy for brain tumors., Case Description: We report on a child who developed rapidly progressive MMS after proton beam therapy for a clivus chordoma. A combined indirect revascularization procedure by encephalo-duro-arterio-synangiosis and encephalo-myo-synangiosis was performed with good neuroradiologic and clinical outcome., Conclusions: Regardless of the presence of known risk factors for MMS, strict neuroimaging surveillance is indicated in all patients treated with radiotherapy including those receiving proton beam therapy. We suggest that an early revascularization procedure should be considered in patients with worsening symptoms and/or sign of neuroradiologic progression of cerebral vasculopathy. This management of MMS could lower the risk of permanent neurologic deficits and improve patients' quality of life., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The authors report their experience on six male patients and one female patient (age range: 58-76 years, median: 67) with facial tumours involving the anterior skull base, undergoing craniofacial resection between January 1992 and May 1994 at the Division of Surgical Oncology in the Tumor Institute, Genoa. Three patients had squamous carcinoma and adenocarcinoma of the nasal fossa; two patients had squamous carcinoma rT4NO and adenocarcinoma rT4NO1 of the maxillary sinus; one patient had squamous carcinoma of the eyelid, and another had squamous carcinoma of the internal chantus. Four patients had had previous radiotherapy, another underwent pre-operative chemoradiotherapy, and only two patients had not been treated before. A proper craniofacial tumour resection was performed in three patients; one patient had a left maxillectomy with ethmoidectomy and orbital exenteration; one patient underwent maxillectomy, resection of the medial and inferior wall of the orbit, ethmoidectomy, and orbital exenteration; one patient underwent maxillectomy, ethmoidectomy, and mucosectomy of the sphenoidal sinus, and one patient had total ethmoidectomy. As for reconstruction procedures of the anterior skull base, lyophilized dura with galeal pericranial flap was commonly used. A myocutaneous flap transposition (transverse rectus abdominis and latissimus dorsi myocutaneous flap) was used in two patients for the reconstruction of the resected tissues and bones of maxillary and orbital regions. Post-operative complications included intraoperative liquorrhea in one patient; one case of early and serious pneumocephalus; flap necrosis occurred following transposition of latissimus dorsi. Median hospital stay was 34 days. After a median follow-up of 18 months (range: 3 to 34 months) five of seven patients (71.4%) are alive and disease-free at 15, 17, 18, 30 and 34 months from surgery.

Invasion of the mandible is found in 22% to 29% of advanced (Stage III-IV) head and neck cancers; only an aggressive surgical technique, such as Commando's operation with subsequent reconstruction of tissue defects, can give a chance of cure to these patients. The reconstruction is feasible both by means of microsurgical free-tissue transfers or with alloplastic materials and myocutaneous flaps. Between 1982 and 1991, 34 patients in Stage III (n = 6; 17.7%) and IV (n = 28; 82.3%) head and neck cancers underwent Commando's operation with different types of reconstruction in 30 patients: pectoralis myocutaneous flap (n = 9), osteo-myocutaneous flap with the underlying segment of the fifth rib (n = 2), myocutaneous flap plus prosthesis (n = 17), or prosthesis alone (n = 2). Two different prostheses were implanted: the linear A-O mandibular reconstruction plate (n = 13), and the Dumbach titanium cage (n = 6). In the group of patients in which the linear A-O mandibular reconstruction plate was used there were four cases of prosthesis dislodgement and major exposure and one case of prosthesis breakage while in patients who were given the Dumbach titanium cage there were four cases of major exposure. Prosthesis removal was required in five and two patients with linear A-O and Dumbach titanium cage prosthesis, respectively. Median survival was 14 months with 28% five-year survival. In our experience, metallic prostheses with a shape and arrangement that allow a distribution of traction forces on a wider surface, with screws drilled in nonaligned points of the mandible, seem to be more reliable as they reduce the risk of dislodgement and breakage.