Nationwide survey of Arima syndrome: revised diagnostic criteria from epidemiological analysis

Rehabilitation Approach for Children With Joubert Syndrome and Related Disorders

Joubert syndrome and related disorders (JSRD) are rare and intractable diseases characterized by delayed psychomotor development, hypotonia and/or ataxia, and abnormal respiratory and eye movements. Cerebellar vermis agenesis and molar tooth signs are distinct on cerebral magnetic resonance imaging (MRI). Children with JSRD present with delayed psychomotor development, including intellectual disability and emotional or behavioral problems. Rehabilitation treatments are provided to promote psychomotor development. However, limited reports and evidence exist on rehabilitation treatments for children with JSRD. Three children with JSRD received rehabilitation treatment. The children received rehabilitation treatment once a week to once every one to two months at our hospital and/or other facilities. All patients received physical, occupational, and speech-language-hearing therapy, depending on their symptoms and conditions. In children with tracheostomies due to abnormal respiration, respiratory physical therapy and speech-language-hearing therapy, including augmentative and alternative communication, were needed. For hypotonia and ataxia, an orthotic intervention was considered in all three cases, and foot or ankle-foot orthoses were used in two cases. Although there is no specific or established rehabilitation method for children with JSRD, appropriate rehabilitation approaches, including physical, occupational, speech-language-hearing therapies and orthotic intervention, should be considered and provided to improve their function and expand their activity and participation. Orthotic intervention for hypotonia seems reasonable for improving gross motor development and function in children with JSRD.

Two Siblings Showing a Mild Phenotype of Joubert Syndrome with a Specific CEP290 Variant

Joubert syndrome (JS) is a genetic neurodevelopmental disorder characterized by lower brainstem dysplasia and cerebellar vermis agenesis termed molar tooth sign (MTS), psychomotor retardation, abnormal respiratory pattern in infancy, and oculomotor abnormalities. Arima syndrome (AS), which is a severe form of JS, is characterized by severe psychomotor retardation, congenital visual impairment, progressive renal dysfunction, and lower brainstem dysplasia from early infancy. Numerous patients with AS expire in early childhood. Recently, c.6012-12T> A in the CEP290 gene was reported as a specific variant of AS. Herein, we report the cases of two siblings showing a phenotype of JS with compound heterozygous mutations (c.6012-12T > A / c.5924delT) in the CEP290 gene. The older sister (aged 19 years) had hypotonia, hypertelorism, and anteverted nares since birth. As a neonate, she developed a transient abnormal respiratory pattern and nystagmus, and brain magnetic resonance imaging (MRI) showed MTS. The younger sister (aged 13 years) exhibited mild hypotonia and pendular nystagmus as a neonate; MRI revealed MTS. Both sisters had psychomotor retardation, oculomotor dysfunction, and bilateral renal cysts with normal renal function. They can walk and have simple conversation. They do not meet the diagnostic criteria for AS, and their symptoms were milder than those of previously reported cases with this specific mutation. This report indicates the expanding spectrum of the CEP290 variant.

Arima syndrome caused by CEP290 specific variant and accompanied with pathological cilium; clinical comparison with Joubert syndrome and its related diseases

OBJECTIVE

Arima syndrome (AS) is a rare disease and its clinical features mimic those of Joubert syndrome or Joubert syndrome-related diseases (JSRD). Recently, we clarified the AS diagnostic criteria and its severe phenotype. However, genetic evidence of AS remains unknown. We explored causative genes of AS and compared the clinical and genetic features of AS with the other JSRD.

PATIENTS AND METHODS

We performed genetic analyses of 4 AS patients of 3 families with combination of whole-exome sequencing and Sanger sequencing. Furthermore, we studied cell biology with the cultured fibroblasts of 3 AS patients.

RESULTS

All patients had a specific homozygous variant (c.6012-12T>A, p.Arg2004Serfs*7) or compound heterozygous variants (c.1711+1G>A; c.6012-12T>A, p.Gly570Aspfs*19;Arg2004Serfs*7) in centrosomal protein 290 kDa (CEP290) gene. These unique variants lead to abnormal splicing and premature termination. Morphological analysis of cultured fibroblasts from AS patients revealed a marked decrease of the CEP290-positive cell number with significantly longer cilium and naked and protruded ciliary axoneme without ciliary membrane into the cytoplasm.

CONCLUSION

AS resulted in cilia dysfunction from centrosome disruption. The unique variant of CEP290 could be strongly linked to AS pathology. Here, we provided AS specific genetic evidence, which steers the structure and functions of centrosome that is responsible for normal ciliogenesis. This is the first report that has demonstrated the molecular basis of Arima syndrome.