Zellweger syndrome caused by PEX6 gene variation in 2 cases and literature review / 中华儿科杂志

Objective: To summarize the clinical features and genetic characteristics of Zellweger spectrum disorder caused by PEX6 gene variation. Methods: This was a case series research. Clinical date and genetic results of 2 neonatal cases of Zellweger syndrome caused by PEX6 gene variation in Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology and Affiliated Hospital of Guangdong Medical University from July 2021 to July 2022 were retrospectively collected and analyzed. Literature up to August 2023 was searched from electronic databases of China National Knowledge Infrastructure (CNKI), Wanfang Data and PubMed with the combined keywords of "Zellweger syndrome" "Zellweger spectrum disorder", and "PEX6 gene" both in Chinese and English. The main clinical features and genetic characteristics of Zellweger spectrum disorder caused by PEX6 gene variation were summarized. Results: The 2 male neonates both developed clinical manifestations as dyspnea, hypotonia, feeding difficulties, enlarged fontanelle, and high palatine arch after birth. Biochemical parameters indicated elevated bile acids, and the cranial ultrasound showed the enlarged bilateral ventricles and subependymal cyst in both 2 neonates. Zellweger syndrome was confirmed by whole exome sequencing, and the results revealed PEX6 gene variation in the 2 neonates, including compound heterozygous variants c.315G>A and c.2095-3T>G, and homozygous variant c.506_507del. Case 1 was hospitalized for 5 days, and case 2 for 32 days; they both died shortly after being discharged (the specific time is unknown). Literature review found 26 patients, including 2 neonates in this study, with Zellweger spectrum disorder caused by PEX6 gene defect reported in 1 Chinese article and 11 English articles. Clinical features included hearing loss (19 cases), developmental delay (19 cases), vision impairment (19 cases), elevated very long chain fatty acids (17 cases), brain malformations (15 cases), hypotonia (12 cases), hepatic insufficiency (12 cases), distinctive facies (10 cases), and dental impairment (9 cases). Compound heterozygous variations dominated the variation types (15 cases), and the frameshift variations (16 cases) were the main pathogenic variations. Conclusions: Zellweger spectrum disorder should be considered when neonates show hypotonia, feeding difficulty, distinctive facial appearance, brain malformations and failure of hearing screening, or when older children show retinitis pigmentosa, sensorineural hearing loss, amelogenesis imperfecta and developmental delays. Detection of genetic variation in the PEX gene is crucial for definitive diagnosis.

Uso de canabidiol como terapia adjuvante em paciente com síndrome de Zellweger: relato de caso / Cannabidiol as adjuvant therapy in a patient with Zellweger syndrome: a case report

RESUMO: Também denominada síndrome cerebrohepatorenal, a síndrome de Zellweger é uma doença autossômica recessiva rara, pertencente ao espectro de erros inatos do metabolismo que afetam os peroxissomos. São causados principalmente por mutações em qualquer um dos 14 genes PEX diferentes que codificam para proteínas envolvidas na montagem do peroxissoma, sendo a mais comum do PEX1. O quadro clínico geralmente é observado no período neonatal e primeira infância, incluindo alterações faciais, hipotonia profunda e ausência de reflexos neonatais, além de disfagia, disfunção hepática e convulsões. O diagnóstico é feito a partir da clínica e testes bioquímicos e confirmados pela visualização da mutação em um dos 14 genes PEX. Como não há tratamento específico, é feito tratamento sintomático. Nosso paciente masculino de 1 ano e 9 meses apresentou a hipotonia congênita como sintoma marcante, além de crises convulsivas recorrentes logo após o nascimento. Evoluiu com necessidade de gastrostomia e estagnação de marcos neuromotores. O diagnóstico foi confirmado aos seis meses, através da dosagem de ácidos graxos de cadeia longa. Crises convulsivas evoluíram de maneira refratária a diversos anticonvulsivantes e com elevada frequência diária, por isso iniciamos canabidiol (CBD-RSHO GOLD) por via enteral que reduziu significantemente as crises. Não há tratamento definitivo para esta enfermidade, sendo importante tratamento sintomático das crises convulsivas e terapias de reabilitação, nesse caso, o uso de (CBD- RSHO GOLD) provocou uma redução de 92% na frequência de crises diárias do paciente. No entanto, não é possível concluir, ainda, melhoras em outros sinais e sintomas. (AU)

ABSTRACT: Also referred to as "brain-liver-kidney" syndrome, the Zellweger syndrome is a rare autosomal recessive disorder, belonging to the spectrum of inborn errors of metabolism that affect peroxisomes. They are caused mainly by mutations in any of the 14 different PEX genes that code for proteins involved in the assembly of peroxisome, being the most common of PEX1. The clinic is usually observed in the neonatal and early childhood period, including facial changes, deep hypotonia, and absence of neonatal reflexes in childhood, in addition to dysphagia, hepatic dysfunction, and seizures. The diagnosis is made from clinical and biochemical tests and confirmed by the visualization of the mutation in one of the 14 PEX genes. Since there is no specific treatment, symptomatic treatment is done. Our 1-year and 9-month-old male patient presented congenital hypotonia as a striking symptom in addition to recurrent seizures shortly after birth. It evolved with the need for gastrostomy and stagnation of neuromotor frames. The diagnosis was confirmed at six months by the measurement of long-chain fatty acids. Convulsive seizures evolved in a manner that was refractory to several anticonvulsants and with a high daily frequency, so we initiated cannabidiol (CBD-RSHO GOLD) by an enteral route that significantly reduced the seizures. Since there is no avail-able treatment for seizures, in this case, the use of CBD-RSHO GOLD reduced by 92% the daily seizure frequency. However, it is not possible to conclude further improvements in other signs and symptoms. (AU)

Molecular characterization of peroxisome biogenesis disorders with Zellweger syndrome spectrum

Peroxisome biogenesis disorders, Zellweger syndrome spectrum [PBD, ZSS] are constituted of three different phenotypically disorders: Zellweger syndrome [ZS], the most severe; neonatal adrenoleuko-dystrophy [NALD]; and infantile refsum disease [IRD], the least severe, that have been originally described based on their biochemical and molecular bases of these disorders which had been fully determined. Individuals with PBD, ZSS usually come to clinical attention in the newborn period or later in childhood. The diagnosis of PBD, ZSS can be definitively determined by biochemical assays, Measurement of plasma very-long-chain fatty acid [VLCFA] levels is the most commonly used and most informative initial screen. Mutations in thirteen different PEX genes - those that encode peroxins, the proteins required for normal peroxisome assembly - have been identified in PBD, ZSS. Mutations in PEX1, the most common cause of PBD, ZSS, are observed in about 68% of affected individuals. Sequence analysis is available clinically for the following seven genes: PEX1, PXMP3 [PEX2], PRXR1 [PEX5], PEX6, PEX10, PEX12, and PEX26

Abnormal Prenatal Sonographic findings in Two Cases of Zellweger Syndrome / 대한주산의학회잡지

Zellweger syndrome is a lethal autosomal recessive disorder characterized by neonatal hypotonia, neonatal seizure, psychomotor retardation, facial dysmorphism, and hepatomegaly. It is characterized by an absence or marked decrease of the number of peroxisomes. Children with Zellweger syndrome rarely survive their first year of life. Diagnosis depends on demonstration of elevated very long chain fatty acid in plasma and deficient activity of the peroxisomal enzyme. Chorionic villi sampling or the biochemical analysis of amniocytes makes it possible to identify a fetus affected by Zellweger syndrome during the first trimester of pregnancy. We experienced two cases of postnatally diagnosed Zellweger syndrome with mild sonographic abnormalities prenatally and report our cases with a brief review of literature.

Zellweger Syndrome : First Confirmed Neonatal Case in Korea

We describe below a case of Zellweger syndrome case with facial dysmorphism, profound hypotonia, and hepatomegaly. He died at the age of 2 months. Zellweger syndrome is a disease marked by the absence of hepatic and renal peroxisomes. Because peroxisomes have many vital anabolic and catabolic functions within the cell, their absence results in profound cellular dysfunction. A biochemical study of plasma revealed elevation of very long chains of fatty acids and pipecolic acid, consistent with peroxisomal disorder. The cultured skin fibroblasts showed a marked decrease in plasmalogen synthesis enzyme : dihydroxyacetonephosphate acyl transferase(DHAP-AT) The clinical characteristics and biochemical findings led to the diagnosis of Zellweger syndrome. The pattern of inheritance is autosomal recessive, hence genetic counseling can help the families. In infantile hypotonia patients with unknown cause, peroxisomal disorder should be included in the differential diagnosis. We report the first confirmed case of Zellweger syndrome by enzyme assay in Korea.

Trastornos de migración neuronal / Neuronal migration Disorders

Los trastornos de migración neuronal representan un grupo de malformaciones congénitas del sistema nervioso, que alteran el proceso en el que millones de células migran de la matríz germinal, hacia el sitio en el que residirán el resto de la vida. De manera particular, en la corteza cerebral provocan cambios importantes en la citoarquitectura, laminación y fisiología neuronal normal. Aparecen como casos esporádicos, determinados genéticamente o causados por agentes externos como infecciones, intoxicaciones, radiaciones, etc. Las entidades nosológicas mejor identificadas incluyen: esquizencefalia, licencefalia, paquigiria, polimicrogiria, heterotopias neuronales y agensia del cuerpo calloso. Los portadores del padecimiento habitualmente presentan síntomas y signos tempranos de la enfermedad, siendo la epilepsia una manifestación clínica dominante. Mediante estudios de tomografía craneal computada (TCC), resonancia magnética (RM), tomografía por emisión de fotón simple (TCEFS) y estudios de inmuno-histoquímica con técnica de Golgi (IHG), recientemente se ha demostrado que estas disgenesias pueden ser una causa frecuente de muchas epilepsias y síndromes epilépticos refractarios a tratamiento médico, considerados previamente como criptogénicos. Cuando se asocian a estos padecimientos estigmas dismórficos, pueden constituir síndromes genéticos como el de Miller-Dieker, Zellweger y Aicardi

Síndrome cerebrohepatorrenal de Zellweger: una enfermedad peroxisomal / Brain-liver-renal Zellweger syndrome: a peroxisomal disease

Se describe el caso clínico de un lactante con dismorfias craneofacilaes, hepatomegalia, quistes renales y disfunción neurológica severa. Los exámenes de rastreo para aminoacidemia, aminoaciduria, ácido láctico y amonio dieron resultados normales, pero había altas concentraciones plasmáticas de ácidos grasos de cadena muy larga, distribución subcelular anormal de la catalasa peroxisomal y fantasmas peroxisomales en fibroblastos cultivados. Estas características clínicas y de laboratorio sustentan el diagnóstico de síndrome de Zellweger

Zellweger syndrome: first reported case in Thailand and literature review.

We describe an infant boy with facial dysmorphism, profound hypotonia, psychomotor retardation, seizure and hepatomegaly. Biochemical study revealed elevation of very long chain fatty acids and pipecolic acid, consistent with peroxisomal disorder. He died at the age of 4 months. Electron microscopic study demonstrated decreased amounts of peroxisomes in liver and kidneys. The clinical characteristic, accompanied the biochemical and microscopic findings led to the diagnosis of Zellweger syndrome. The recognition of this syndrome is important since it is a fatal disease. The pattern of inheritance is autosomal recessive, hence genetic counseling is necessary. We emphasize that peroxisomal disorder should be included in the differential diagnosis in patients with infantile hypotonia. This patient is the first reported case of Zellweger syndrome in Thailand.

Zellweger (cerebro-hepato-renal) syndrome: first brazilian case with confirmed peroxisomal defect

A síndrome de Zellweger (ZS) é uma doença recessiva causada por uma deficiência generalizada das funçöes peroxissônicas, sendo um exemplo ilustrativo de uma doença metabólica herdada que usualmente chama a atençäo já no período neonatal pelo seu quadro dismórfico típico. Embora a suspeita de ZS seja freqüentemente levantada nas unidades neonatais, o diagnóstico é raramente confirmado uma vez que ele exige procedimentos bioquímicos sofisticados. Neste artigo é descrito um paciente com ZS que, tanto quanto estejamos informados, é o primeiro caso brasileiro no qual o defeito peroxissômico foi confirmado bioquimicamente. Os autores ressaltam a importância da confirmaçäo bioquímica do diagnóstico de ZS, uma vez que ela permite näo apenas um melhor delineamento do fenótipo da síndrome mas principalmente porque permite a prevençäo de casos adicionais através do aconselhamento genético e do diagnóstico pré-natal