1Área da Mulher, Criança e Adolescente, Hospital Dona Estefânia, Centro Hospitalar Universitário de Lisboa Central, Lisboa, Portugal
2Serviço de Genética Médica, Área da Mulher, Criança e Adolescente, Hospital Dona Estefânia, Centro Hospitalar Universitário de Lisboa Central, Lisboa, Portugal
3Centro de Referência de Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário de Lisboa Central, Lisboa, Portugal
4Serviço de Neuropediatria, Área da Mulher, Criança e Adolescente, Hospital Dona Estefânia, Centro Hospitalar Universitário de Lisboa Central, Lisboa, Portugal
- Poster -15th International Symposium of Sociedade Portuguea de Doenças Metabólicas
- Coimbra, 14 a 16 março de 2019
Background: Congenital disorders of glycosylation (CDG) are a heterogeneous group of diseases that result from disruption of the normal N-glycosylation pathway. SLC35A2 gene, on the X chromosome, codes for the only known transporter of UDP-galactose to the Golgi apparatus. The phenotype associated to variants of SLC35A2 includes developmental delay, early epileptic encephalopathy with hypsarrhythmia, hypotonia, dysmorphic features, skeletal abnormalities and cortical visual impairment.
Case Report: A 2 months-old girl, second child of non-consanguineous parents, born at term after an eventful pregnancy, was admitted with irritability and clusters of flexor spasms, mainly during the sleep-wake transition. On physical examination she had slight dysmorphic features, did not fixed or follow, and had axial hypotonia combined with limb hypertonia. Electroencephalogram showed hypsarrhythmia. Brain CT and MRI were normal. Ophthalmologic evaluation revealed ocular fundus with multiple yellowish white points deposits, and zones of hyperpigmentation on the periphery. Extensive metabolic investigation detected a type 2 pattern isoelectric focusing of transferrin. Next Generation Sequencing (NGS) panel for neurometabolic diseases identified a c.745del mutation at exon 5 in the SLC35A2 gene in heterozygosity (X-linked). Epilepsy was difficult to control with multiple trials of medication including ACTH, topiramate, vigabatrin and levetiracetam. The association of ketogenic diet was useful and partial control of seizures was achieved.
Discussion: Severe early-onset epilepsy is an unusual presentation of CDGs in general and seems to be unique in SLC35A2- related CDGs. Seizure control is difficult but can be achieved, at least partially, with anti-epileptic drugs combined with ketogenic diet.