A novel heterozygous TMEM63A variant in a familial case with early onset nystagmus, severe hypomyelination, and a favorable adult prognosis.

Heterozygous transmembrane protein 63A (TMEM63A) variants cause transient infantile hypomyelinating leukodystrophy-19, which features remarkable natural resolution of clinical and imaging findings during childhood. Previous reports have mainly described de novo variants lacking detailed familial cases. Herein, we describe the clinical course of familial cases with a TMEM63A variant. A 5-month-old girl presented with nystagmus, global hypotonia, and difficulty swallowing since birth. Brain magnetic resonance imaging at 1.5 and 5 months revealed diffuse hypomyelination. Her mother, maternal aunt, and grandfather had nystagmus and motor developmental delays in infancy, which resolved spontaneously during childhood. Compared with these cases, the proband's motor developmental delay was profound, and she was the only one with feeding difficulties, necessitating nasogastric tube feeding. Genetic testing revealed a heterozygous TMEM63A variant (NM_014698.3:c.1658G>A, p.(Gly553Asp)) in the proband and her family. This is the first three-generation familial report of a TMEM63A variant that provides insight into its history and heterogeneity.

Novel compound heterozygous ATP1A2 variants in a patient with fetal akinesia/hypokinesia sequence.

ATP1A2 encodes a subunit of sodium/potassium-transporting adenosine triphosphatase (Na+ /K+ -ATPase). Heterozygous pathogenic variants of ATP1A2 cause familial hemiplegic migraine, alternating hemiplegia of childhood, and developmental and epileptic encephalopathy. Biallelic loss-of-function variants in ATP1A2 lead to fetal akinesia, respiratory insufficiency, microcephaly, polymicrogyria, and dysmorphic facies, resulting in fetal death. Here, we describe a patient with compound heterozygous ATP1A2 variants consisting of missense and nonsense variants. He survived after birth with brain malformations and the fetal akinesia/hypokinesia sequence. We report a novel type of compound heterozygous variant that might extend the disease spectrum of ATP1A2.

The Efficacy of a Ketogenic Diet in a Case With Febrile Infection-Related Epilepsy Syndrome in the Chronic Phase: A Case Report.

Although the treatment strategy for febrile infection-related epilepsy syndrome (FIRES) is improving, current research focuses on acute management. Evidence for the management of the chronic phase is limited. We present the case of a 19-year-old woman with FIRES who showed excellent response to a ketogenic diet (KD) administered in the chronic phase. At the age of four years, she presented with new-onset super-refractory status epilepticus after a febrile episode. She was diagnosed with FIRES and had profound motor and cognitive deterioration and drug-resistant epilepsy. From the age of 17, she experienced numerous seizures that often led to status epilepticus with respiratory failure, necessitating laryngotracheal separation and nocturnal mechanical ventilation. To improve seizure control, we planned a KD for the first time 15 years after the onset of FIRES. We introduced a classic KD (ketogenic ratio, 3:1) using blended meals through gastrotomy. Two months after starting the KD, she experienced a decrease in seizure frequency and duration. Moreover, as unexpected stabilization of respiration was achieved, mechanical ventilation was stopped. Our case implies that KD may be a promising treatment option for patients with FIRES in the chronic phase, as is believed to be the case in the acute phase.