Poirier-Bienvenu Syndrome

Inspired by a patient

Orsini A, Santangelo A, Bravin F, Bonuccelli A, Peroni D, Battini R, Foiadelli T, Bertini V, Valetto A, Iacomino M, Nigro V, Torella AL, Scala M, Capra V, Vari MS, Fetta A, Di Pisa V, Montanari F, Epifanio R, Bonanni P, Giorda R, Operto F, Pastorino G, Sarigecili E, Sardaroglu E, Okuyaz C, Bozdogan S, Musante L, Faletra F, Zanus C, Ferretti A, Vigevano F, Striano P, Cordelli DM. Expanding Phenotype of Poirier-Bienvenu Syndrome: New Evidence from an Italian Multicentrical Cohort of Patients. Genes (Basel). 2022 Jan 30;13(2):276. doi: 10.3390/genes13020276. PMID: 35205321; PMCID: PMC8872204.

Abstract

Background: Poirier-Bienvenu Neurodevelopmental Syndrome (POBINDS) is a rare disease linked to mutations of the CSNK2B gene, which encodes for a subunit of caseinkinase CK2 involved in neuronal growth and synaptic transmission. Its main features include early-onset epilepsy and intellectual disability. Despite the lack of cases described, it appears that POBINDS could manifest with a wide range of phenotypes, possibly related to the different mutations of CSNK2B.

Methods: Our multicentric, retrospective study recruited nine patients with POBINDS, detected using next-generation sequencing panels and whole-exome sequencing. Clinical, laboratory, and neuroimaging data were reported for each patient in order to assess the severity of phenotype, and eventually, a correlation with the type of CSNK2B mutation.

Results: We reported nine unrelated patients with heterozygous de novo mutations of the CSNK2B gene. All cases presented epilepsy, and eight patients were associated with a different degree of intellectual disability. Other features detected included endocrinological and vascular abnormalities and dysmorphisms. Genetic analysis revealed six new variants of CSNK2B that have not been reported previously.

Conclusion: Although it was not possible to assess a genotype-phenotype correlation in our patients, our research further expands the phenotype spectrum of POBINDS patients, identifying new mutations occurring in the CSNK2B gene.

Chen X, Han Y, Li X, Huang S, Yuan H, Qin Y. Case report: Two cases of Poirier-Bienvenu neurodevelopmental syndrome and review of literature. Front Pediatr. 2023 Mar 20;11:967701. doi: 10.3389/fped.2023.967701. PMID: 37020656; PMCID: PMC10067874.

Abstract

The Poirier-Bienvenu neurodevelopmental syndrome (POBINDS) is a rare disease caused by mutations in the CSNK2B gene, which is characterized by intellectual disability and early-onset epilepsy. Mosaicism has not been previously reported in CSNK2B gene. POBINDS is autosomal dominant and almost all reported cases were de novo variants. Here, we report two patients were diagnosed with POBINDS. Using Whole Exome Sequencing (WES), we detected two novel CSNK2B variants in the two unrelated individuals: c.634_635del (p.Lys212AspfsTer33) and c.142C > T (p.Gln48Ter) respectively. Both of them showed mild developmental delay with early-onset and clustered seizures. The patient with c.634_635del(p.Lys212AspfsTer33) variant was mutant mosaicism, and the proportion of alleles in peripheral blood DNA was 28%. Further, the literature of patients with a de novo mutation of the CSNK2B gene was reviewed, particularly seizure semiology and genotype-phenotype correlations.

Bonanni P, Baggio M, Duma GM, Negrin S, Danieli A, Giorda R. Developmental and epilepsy spectrum of Poirier-Bienvenu neurodevelopmental syndrome: Description of a new case study and review of the available literature. Seizure. 2021 Dec;93:133-139. doi: 10.1016/j.seizure.2021.10.019. Epub 2021 Oct 27. PMID: 34740143.

Abstract

Aim: To better characterize the clinical phenotype of Poirier-Bienvenu neurodevelopmental syndrome (OMIM ID: 618,732) due to pathogenic variants of the CSNK2B gene.

Method: We reviewed the electro-clinical and developmental data of all 14 patients with de novo mutations of the CSNK2B gene reported in the literature and describe a further individual with a novel CSNK2B pathogenic variant.

Results: Clustered generalized tonic-clonic or myoclonic seizures with onset before the age of 18 months and delayed neurodevelopment were present in more than 75% of patients. Epilepsy was pharmaco-resistant in 40%. All the individuals (27%) with normal neurological development had pharmaco-sensitive epilepsy. The severity of cognitive and motor impairments was higher in the group with pharmaco-resistant epilepsy, and a statistically significant correlation between seizure control and the severity of cognitive impairment was documented (χ2(3) = 9.44; p = .024) INTERPRETATION: Early seizure onset, clustered seizures and delayed development in both males and females were early clinical markers in most patients with CSNK2B mutations. The entity of neurodevelopmental abnormalities was related to epilepsy severity. Prospective studies are required to better assess the relationship between epilepsy and developmental outcomes in this condition.

Yang Q, Zhang Q, Yi S, Qin Z, Shen F, Ou S, Luo J, He S. De Novo CSNK2B Mutations in Five Cases of Poirier-Bienvenu Neurodevelopmental Syndrome. Front Neurol. 2022 Mar 16;13:811092. doi: 10.3389/fneur.2022.811092. PMID: 35370893; PMCID: PMC8965697.

Abstract

The Poirier-Bienvenu neurodevelopmental syndrome is an autosomal dominant disorder characterized by intellectual disability and epilepsy. The disease is caused by mutations in the CSNK2B gene, which encodes the beta subunit of casein kinase II, and it has important roles in neuron development and synaptic transmission. In this study, five Chinese patients were diagnosed with Poirier-Bienvenu neurodevelopmental syndrome caused by CSNK2B mutations by whole exome sequencing. We detected four different de novo variants of the CSNK2B gene in these five unrelated Chinese patients: two novel mutations, namely, c.100delT (p.Phe34fs*16) and c.158_159insA (p.Asp55fs*4), and two recurrent mutations, namely, c.1A>G (p.Met1?) and c.332 G >C (p.R111P). All five patients showed mild-to-profound intellectual disabilities/or learning disabilities and developmental delays, with or without seizures. Although intellectual disability/developmental delay and epilepsy are the most common manifestations of CSNK2B deficiency, the clinical phenotypes of probands are highly variable, and there is no significant correlation between genotype and phenotype. An abnormal stature may be another common manifestation of CSNK2B deficiency. Here, we report the effects of growth hormone (GH) therapy on the patients' linear height. In conclusion, Poirier-Bienvenu neurodevelopmental syndrome is a highly heterogeneous disease caused by mutations in the CSNK2B gene. The phenotype was highly variable, and no significant correlation of genotype and phenotype was found. Patients with short-stature and CSNK2B deficiency may benefit from GH therapy. The identification and characterization of these novel variants will expand the genotypic and phenotypic spectrum of Poirier-Bienvenu neurodevelopmental syndrome.