The utility of whole exome sequencing for identification of the molecular etiology in autosomal recessive developmental and epileptic encephalopathies

Neuronal ceroid lipofuscinosis type 11 diagnosed patient with bi-allelic variants in GRN gene: case report and review of literature

OBJECTIVES

Neuronal ceroid lipofuscinosis type 11 (NCL11) is a rare disease that presents with progressive cognitive decline, epilepsy, visual impairment, retinal atrophy, cerebellar ataxia and cerebellar atrophy. We present herein a case of NCL11 in a patient diagnosed with neuromotor developmental delay, epilepsy, bronchiolitis obliterans and hypothyroidism.

CASE PRESENTATION

A 4-year-old male patient was admitted to our clinic with global developmental delay and a medical history that included recurrent hospitalizations for pneumonia at the age of 17 days, and in months 4, 5 and 7. Family history revealed a brother with similar clinical findings (recurrent pneumonia, hypothyroidism, hypotonicity, swallowing dysfunction and neuromotor delay) who died from pneumonia at the age of 22 months. Computed tomography of the thorax was consistent with bronchiolitis obliterans, while epileptic discharges were identified on electroencephalogram with a high incidence of bilateral fronto-centro-temporal and generalized spike-wave activity but no photoparoxysmal response. Cranial MRI revealed T2 hyperintense areas in the occipital periventricular white matter and volume loss in the white matter, a thin corpus callosum and vermis atrophy. A whole-exome sequencing molecular analysis revealed compound heterozygous c.430G>A (p.Asp144Asn) and c.415T>C (p.Cys139Arg) variants in the GRN gene.

CONCLUSIONS

The presented case indicates that NCL11 should be taken into account in patients with epilepsy and neurodegenerative diseases.

PEBAT, an Intriguing Neurodegenerative Tubulinopathy Caused by a Novel Homozygous Variant in TBCD: A Case Series and Literature Review

Progressive encephalopathy with brain atrophy and thin corpus callosum (PEBAT) is a severe and rare progressive neurodegenerative disease (OMIM 617913). This condition has been described in individuals with pathogenic variants affecting tubulin-specific chaperone protein D (TBCD), which is responsible for proper folding and assembly of tubulin subunits. Here we describe two unrelated infants from Central America presenting with worsening neuromuscular weakness, respiratory failure, polyneuropathy, and neuroimaging findings of severe cerebral volume loss with thin corpus callosum. These individuals harbored the same homozygous variant of uncertain significance in the TBCD gene on whole exome sequencing (WES). Predicted protein modeling of this variant confirmed disruption of the protein helix at the surface of TBCD. The goal of this report is to emphasize the importance of rapid WES, careful interpretation of uncertain variants, prognostication, and family counseling especially when faced with a neurodegenerative clinical course.

Daily Outpatient Physical Therapy for a Toddler With a Neurodegenerative Disease: A Case Report

PURPOSE

This case report highlights the potential value of delivering a high-dose physical therapy (PT) intervention for a child with a neurodegenerative disease. We include developmental outcomes for a 23-month-old toddler with biallelic TBCD gene mutations following daily outpatient PT.

SUMMARY OF KEY POINTS

The child had clinical improvements in gross and fine motor, cognition, expressive and receptive language, socioemotional, and adaptive behavior function as determined through Goal Attainment Scaling, Gross Motor Function Measure, and Bayley Scales of Infant and Toddler Development following daily PT intervention.

STATEMENT OF CONCLUSION AND RECOMMENDATIONS FOR CLINICAL PRACTICE

High-dose outpatient PT may be beneficial for a child with a neurodegenerative disease at some time frames. In selected cases, if the neurodegenerative disease slowly progresses, high-dose PT may be a treatment option to promote motor change.

Tubulin Folding Cofactor D Deficiency: Missing the Diagnosis With Whole Exome Sequencing

Two siblings with an early onset of a neurodegenerative disease were presented with muscular hypotonia, secondary microcephaly, and severe developmental delay. Seizures were refractory to treatment but could be controlled with a ketogenic diet. Over the course of 5 years, whole exome sequencing (WES) was performed twice in both children. The first time the diagnosis was missed. The next one revealed compound heterozygous mutations in the gene coding for the tubulin folding cofactor D. Technical improvements in WES mandated a new investigation after a few years in children where the diagnosis has not been found.