[NFIX gene mutation causes Marshall-Smith syndrome in a pair of identical twins and literature review]. / NFIXåŸºå› å˜å¼‚å¯¼è‡´ä¸€å¯¹åŒåµåŒèƒžèƒŽMarshall-Smithç»¼åˆå¾å¹¶æ–‡çŒ®å¤ä¹ .

This article reports on the clinical and genetic characteristics of monozygotic twins with Marshall-Smith syndrome (MRSHSS) due to a mutation in the NFIX gene, along with a review of related literature. Both patients presented with global developmental delays, a prominent forehead, shallow eye sockets, and pectus excavatum. Genetic testing revealed a heterozygous splicing site mutation c.697+1G>A in both children, with parents showing wild-type at this locus. According to the guidelines of the American College of Medical Genetics and Genomics, this mutation is considered likely pathogenic and has not been previously reported in the literature. A review of the literature identified 32 MRSHSS patients with splicing/frameshift mutations. Accelerated bone maturation and moderate to severe global developmental delay/intellectual disability are the primary clinical manifestations of patients with MRSHSS. Genetic testing results are crucial for the diagnosis of this condition.

Management of an older Marshall-Smith syndrome patient: a review of literature of MSS and craniosynostosis.

Marshall-Smith Syndrome (MSS) is a rare progressive developmental disorder that severely impairs a patient's intellectual development and physical health. The only known cause for MSS is a mutation in the nuclear factor 1 X (NFIX) gene. This mutation affects neuronal development and protein transcription. Historically, most patients with MSS do not survive beyond 3 years of age. Reports of ocular findings are limited. We report a case of a 9-year-old MSS patient with progressive craniosynostosis, elevated intracranial pressure, and catastrophic ocular complications. A comprehensive PubMed literature search from 2018 to August 2022 updating a previous review of older literature produced 72 articles relating to MSS, which are reviewed.

Fronto-orbital advancement in a patient with Marshall-Smith syndrome: a case report and review of the literature.

OBJECTIVE: The present report aimed to document the clinical features of a case of Marshall-Smith syndrome (MSS), an extremely rare embryonic developmental disorder with associated craniosynostosis. PATIENT AND METHOD: We presented herein a case of a 2-year-old female patient with MSS who underwent fronto-orbital advancement for multisuture craniosynostosis. RESULTS: The patient's proptosis improved after surgery, and no further surgical intervention was required for corneal exposure. A second FOA followed by revision tarsorrhaphy further improved eye closure. CONCLUSION: Surgical procedures to correct dysplastic features and limit neurological impairment are a worthwhile supportive treatment for improving the quality of life and general condition of patients with MSS.

Development, behaviour and sensory processing in Marshall-Smith syndrome and Malan syndrome: phenotype comparison in two related syndromes.

BACKGROUND: Ultrarare Marshall-Smith and Malan syndromes, caused by changes of the gene nuclear factor I X (NFIX), are characterised by intellectual disability (ID) and behavioural problems, although questions remain. Here, development and behaviour are studied and compared in a cross-sectional study, and results are presented with genetic findings. METHODS: Behavioural phenotypes are compared of eight individuals with Marshall-Smith syndrome (three male individuals) and seven with Malan syndrome (four male individuals). Long-term follow-up assessment of cognition and adaptive behaviour was possible in three individuals with Marshall-Smith syndrome. RESULTS: Marshall-Smith syndrome individuals have more severe ID, less adaptive behaviour, more impaired speech and less reciprocal interaction compared with individuals with Malan syndrome. Sensory processing difficulties occur in both syndromes. Follow-up measurement of cognition and adaptive behaviour in Marshall-Smith syndrome shows different individual learning curves over time. CONCLUSIONS: Results show significant between and within syndrome variability. Different NFIX variants underlie distinct clinical phenotypes leading to separate entities. Cognitive, adaptive and sensory impairments are common in both syndromes and increase the risk of challenging behaviour. This study highlights the value of considering behaviour within developmental and environmental context. To improve quality of life, adaptations to environment and treatment are suggested to create a better person-environment fit.

Successful respiratory management of a Marshall-Smith syndrome patient with a tracheo-innominate artery fistula.

BACKGROUND: Tracheo-innominate artery fistula (TIF) is a life-threatening complication of tracheostomy. We describe perioperative management for innominate artery transection in a case with TIF. CASE PRESENTATION: A 4-year-old Japanese female with Marshal-Smith syndrome presented for management of TIF. She underwent tracheostomy at the age of 3 months and an uncuffed tracheostomy tube was inserted. One month before admission to our hospital, intermittent tracheal bleeding, suggesting TIF, occurred. Although we considered to change to a cuffed endotracheal tube, craniofacial abnormality suggested difficult oral intubation, and there was a possibility of rebleeding. Finally, innominate artery transection was performed under total intravenous anesthesia without changing the tracheostomy tube. Surgery completed uneventfully and she received mechanical ventilation under sedation for a day, followed by weaning without complications. CONCLUSIONS: A cuffed tracheostomy tube should have been inserted before surgery for effective hemostasis against sudden bleeding from TIF even though conversion to oral intubation was difficult.

Malan syndrome: Extension of genotype and phenotype spectrum.

Malan syndrome and Marshall-Smith syndrome (MSS) are allelic disorders caused by mutation in NFIX gene. We report a 3-year- 6 months- old female with clinical features suggestive of Malan syndrome with mutation in exon 2 of NFIX gene. NFIX gene, where most of the mutations in Malan syndrome are located. She did not have advanced bone age. The radiographs of long bones showed metaphyseal changes which were not reported previously. This study reports the first mutation proven case from India and highlights the overlap between MSS and Malan syndrome.

Further delineation of Malan syndrome.

Malan syndrome is an overgrowth disorder described in a limited number of individuals. We aim to delineate the entity by studying a large group of affected individuals. We gathered data on 45 affected individuals with a molecularly confirmed diagnosis through an international collaboration and compared data to the 35 previously reported individuals. Results indicate that height is > 2 SDS in infancy and childhood but in only half of affected adults. Cardinal facial characteristics include long, triangular face, macrocephaly, prominent forehead, everted lower lip, and prominent chin. Intellectual disability is universally present, behaviorally anxiety is characteristic. Malan syndrome is caused by deletions or point mutations of NFIX clustered mostly in exon 2. There is no genotype-phenotype correlation except for an increased risk for epilepsy with 19p13.2 microdeletions. Variants arose de novo, except in one family in which mother was mosaic. Variants causing Malan and Marshall-Smith syndrome can be discerned by differences in the site of stop codon formation. We conclude that Malan syndrome has a well recognizable phenotype that usually can be discerned easily from Marshall-Smith syndrome but rarely there is some overlap. Differentiation from Sotos and Weaver syndrome can be made by clinical evaluation only.

Sindrome de Marshall- Smith en mujer adulta: nuevos retos en anticoncepción / Marshall-Smith syndrome in an adult woman: new challenges in contraception

Se presenta el caso de una mujer de 38 años con Síndrome de Marshall-Smith. Se trata de una enfermedad rara de etiología desconocida, cuyas características incluyen anomalías craneofaciales, maduración ósea acelerada, alteraciones en el desarrollo neurológico y en las vías respiratorias con compromiso de la vía aérea y escasa supervivencia a largo plazo debido a problemas respiratorios. Sin embargo, los avances en el soporte respiratorio han permitido que algunos pacientes lleguen a la etapa adulta. Nuestra paciente, sin retraso intelectual ni psicomotor, solicita método anticonceptivo. Los pacientes con enfermedades raras necesitan ser atendidos con especial dedicación intentando reducir al mínimo la transmisión genética de dichas entidades, y mejorando al máximo su calidad de vida. Se ofrece un método anticonceptivo reversible de larga duración, sin riesgos para la evolución de su patología respiratoria, y atendiendo a los criterios medicos de elegibilidad de método anticonceptivo de la OMS, se indica la utilización de un implante subdérmico de etonogestrel. Con un perfil de seguridad y farmacocinética equivalente a los métodos de solo gestágeno y mayor comodidad.

A 38-year-old female patient with a history of Marshall-Smith syndrome is reported. It is a rare congenital disorder of unknown aetiology, which features include craneo facial dysmorphism, accelerated bone maturation, neurodevelopmental abnormalities, and upper and lower airways compromise. Long term survival is a problem due to respiratory complications, but it has decreased since airway support has improved, and that allows survival into adulthood. Our patient has neither intelectual nor psychomotor delay, so she asks for contraception method. As a rare genetic condition it needs to be attended with special consideration in order to reduce the disorder's transmission and to increase the life's quality of patients. A secure contraception method should be offered with no risk at all, attending to medical elegibility criteria for contraception use. We considered progestogen-only options and the patient's choice was etonogestrel subcutaneous implant.

Marshall-Smith syndrome: Novel pathogenic variant and previously unreported associations with precocious puberty and aortic root dilatation.

Marshall-Smith Syndrome (MRSHSS) is a very rare genetic disorder characterized by failure to thrive and characteristic dysmorphic features associated with accelerated osseous maturation. We present a nine-year-old girl who was diagnosed with MRSHSS based on characteristic clinical features supported by the identification of a novel de novo pathogenic variant in the NFIX gene. The patient also presented with precocious puberty diagnosed at five years of age and had an abnormal GnRH stimulation test indicative of central precocious puberty. Central precocious puberty has not been described in association with MRSHSS previously in the medical literature and broadens our knowledge of the natural history of MRSHSS. The causes of advanced bone age in this syndrome are also reviewed. Additionally, the patient showed progressive dilatation of the aortic root. Although connective tissue abnormalities have been described in association with MRSHSS, aortic root dilatation has not. Understanding the mechanism of comorbidities such as advanced bone age and aortic root dilatation in MRSHSS patients enables future development of anticipatory guidance, preventative care measures, and treatment guidelines.

Deletions in the 3' part of the NFIX gene including a recurrent Alu-mediated deletion of exon 6 and 7 account for previously unexplained cases of Marshall-Smith syndrome.

Marshall-Smith syndrome (MSS) is a very rare malformation syndrome characterized by typical craniofacial anomalies, abnormal osseous maturation, developmental delay, failure to thrive, and respiratory difficulties. Mutations in the nuclear factor 1/X gene (NFIX) were recently identified as the cause of MSS. In our study cohort of 17 patients with a clinical diagnosis of MSS, conventional sequencing of NFIX revealed frameshift and splice-site mutations in 10 individuals. Using multiplex ligation-dependent probe amplification analysis, we identified a recurrent deletion of NFIX exon 6 and 7 in five individuals. We demonstrate this recurrent deletion is the product of a recombination between AluY elements located in intron 5 and 7. Two other patients had smaller deletions affecting exon 6. These findings show that MSS is a genetically homogeneous Mendelian disorder. RT-PCR experiments with newly identified NFIX mutations including the recurrent exon 6 and 7 deletion confirmed previous findings indicating that MSS-associated mutant mRNAs are not cleared by nonsense-mediated mRNA decay. Predicted MSS-associated mutant NFIX proteins consistently have a preserved DNA binding and dimerization domain, whereas they grossly vary in their C-terminal portion. This is in line with the hypothesis that MSS-associated mutations encode dysfunctional proteins that act in a dominant negative manner.