Patterns, evolution, and severity of striatal injury in insidious- versus acute-onset glutaric aciduria type 1

Impairment of neuromotor development and cognition associated with histopathological and neurochemical abnormalities in the cerebral cortex and striatum of glutaryl-CoA dehydrogenase deficient mice

Patients with glutaric acidemia type I (GA I) manifest motor and intellectual disabilities whose pathogenesis has been so far poorly explored. Therefore, we evaluated neuromotor and cognitive abilities, as well as histopathological and immunohistochemical features in the cerebral cortex and striatum of glutaryl-CoA dehydrogenase (GCDH) deficient knockout mice (Gcdh-/-), a well-recognized model of GA I. The effects of a single intracerebroventricular glutaric acid (GA) injection in one-day-old pups on the same neurobehavioral and histopathological/immunohistochemical endpoints were also investigated. Seven-day-old Gcdh-/- mice presented altered gait, whereas those receiving a GA neonatal administration manifested other sensorimotor deficits, including an abnormal response to negative geotaxis, cliff aversion and righting reflex, and muscle tone impairment. Compared to the WT mice, adult Gcdh-/- mice exhibited motor impairment, evidenced by poor performance in the Rota-rod test. Furthermore, neonatal GA administration provoked long-standing short- and long-term memory impairment in adult Gcdh-/- mice. Regarding the histopathological features, a significant increase in vacuoles and neurodegenerative cells was observed in both the cerebral cortex and striatum of 15- and 60-day-old Gcdh-/- mice and was more pronounced in mice injected with GA. Neuronal loss (decrease of NeuN staining) was also significantly increased in the cerebral cortex and striatum of Gcdh-/- mice, particularly in those neonatally injected with GA. In contrast, immunohistochemistry of MBP, astrocytic proteins GFAP and S100B, and the microglial marker Iba1 was not changed in 60-day-old Gcdh-/- mice, suggesting no myelination disturbance, reactive astrogliosis, and microglia activation, respectively. These data highlight the neurotoxicity of GA and the importance of early treatment aiming to decrease GA accumulation at early stages of development to prevent brain damage and learning/memory disabilities in GA I patients.

Orthopaedic manifestations of glutaric acidemia Type 1

PURPOSE

Glutaric acidemia type 1 (GA1), a rare hereditary metabolic disease caused by biallelic mutations of GCDH, can result in acute or insidious striatal degeneration within the first few years of life. We reviewed the orthopaedic sequelae and management of 114 neurologically injured patients with a confirmed molecular diagnosis of GA1.

METHODS

We performed a retrospective chart review spanning 28 years identifying 114 GA1 patients, most from the Old Order Amish population of Lancaster County, Pennsylvania, who were homozygous for a pathogenic founder variant of GCDH (c.1262C>T). We collected demographics, medical comorbidities, muscle tone patterns, Gross Motor Function Classification System level, gastrostomy tube status, seizure history, inpatient events, orthopaedic diagnoses and operative characteristics.

RESULTS

Over an average follow-up of 4.7 ± 3.4 years, 24 (21%) of 114 patients had musculoskeletal problems requiring orthopaedic consultation. Scoliosis (n = 14), hip dislocation (n = 8/15 hips), hip subluxation (n = 2/three hips), and windswept hip deformity (n = 2) in the spine and hip joint were most common. In total, 35 orthopaedic surgeries were performed in 17 (71%) patients. The most common primary operations were one-stage procedures with proximal femoral varus derotation osteotomy and/or pelvic osteotomy (n = 8/14 hips) for subluxation or dislocation. In all, 11 patients had posterior spinal fusion for severe scoliosis. With the recommended metabolic management, there were no disease-specific complications in this cohort.

CONCLUSIONS

Children with GA1 who have static striatal lesions are at risk for musculoskeletal complications, especially scoliosis and hip dislocation, and appropriate operative management requires consultation with a metabolic specialist with specific considerations for fluid management and nutrition.

LEVEL OF EVIDENCE

IV.

Genetic mimics of cerebral palsy

The term "cerebral palsy mimic" is used to describe a number of neurogenetic disorders that may present with motor symptoms in early childhood, resulting in a misdiagnosis of cerebral palsy. Cerebral palsy describes a heterogeneous group of neurodevelopmental disorders characterized by onset in infancy or early childhood of motor symptoms (including hypotonia, spasticity, dystonia, and chorea), often accompanied by developmental delay. The primary etiology of a cerebral palsy syndrome should always be identified if possible. This is particularly important in the case of genetic or metabolic disorders that have specific disease-modifying treatment. In this article, we discuss clinical features that should alert the clinician to the possibility of a cerebral palsy mimic, provide a practical framework for selecting and interpreting neuroimaging, biochemical, and genetic investigations, and highlight selected conditions that may present with predominant spasticity, dystonia/chorea, and ataxia. Making a precise diagnosis of a genetic disorder has important implications for treatment, and for advising the family regarding prognosis and genetic counseling. © 2019 International Parkinson and Movement Disorder Society.