Malonyl coenzyme A decarboxylase deficiency with a novel mutation.

Malonyl-CoA, a product of acetyl-CoA carboxylase is a metabolic intermediate in lipogenic tissues that include liver and adipose tissue, where it is involved in the de novo fatty acid synthesis and elongation. Malonyl-CoA decarboxylase (MLYCD, E.C.4.1.1.9), a 55-kDa enzyme catalyses the conversion of malonyl-CoA to acetyl-CoA and carbon dioxide, thus providing a route for disposal of malonyl-CoA from mitochondria and peroxisomes, whereas in the cytosol, the malonyl-CoA pool is regulated by the balance of MLYCD and acetyl-CoA carboxylase activities. So far, 34 cases with different MLYCD gene defects comprising point mutations, stop codons, and frameshift mutations have been reported in the literature. Here, we describe the follow-up of a patient affected by malonic aciduria upon neonatal onset. Molecular analysis showed novel homozygous mutations in the MLYCD gene. Our findings expand the number of reported cases and add a novel variant to the repertoire of MLYCD mutations.

CLN3-Associated NCL Case with a Preliminary Diagnosis of Niemann Pick Type C.

Introduction: Neuronal ceroid lipofuscinoses (NCLs) are a broad class of inherited lysosomal storage disorders. Known mutations in at least 13 different genes can result in NCL with variable ages of onset, symptoms, and pathologic findings. Generally, these patients experience cognitive and motor decline, seizures, visual impairment, and premature death. Pathologically, NCL patients display heterogeneous histologic abnormalities, but consistently exhibit neuronal loss, reactive gliosis, and lysosomal accumulation of autofluorescent storage material or lipopigment. Juvenile-onset NCL has been classically referred to as Batten disease. By far the most prevalent NCL is CLN3-associated disease. It is an autosomal recessive condition that is usually caused by mutations in the ceroid-lipofuscinosis, neuronal 3 (CLN3) gene. CLN3 encodes battenin, a ubiquitously expressed transmembrane protein of unknown function that is associated with cellular homeostasis and neuronal survival. The initial clinical symptom of CLN3-associated NCL is central vision loss, which is usually detected between 4 and 9 years of age. Seizures typically begin early in the second decade of life, and affected individuals rarely live beyond their mid-20ies. Case Presentation: Herein, we describe a 16-year-old patient with CLN3-related juvenile NCL with a preliminary diagnosis of Niemann Pick Type C disease. The proband showed characteristic clinical signs, including epilepsy, ataxia, psychomotor regression, dementia, and visual impairment with an unusual elevation of lyso-sphingomyelin-509 (Lyso-SM-509; 812 nmol/L, normal 1-33 nmol/L). A homozygous NM_001042432.2(CLN3):c.233dup (p.Thr80fs) variant was detected at exon 4 of CLN3. Diagnosis of NCL was difficult due to the pronounced elevation of LysoSM-509. Discussion: LysoSM-509 is a biomarker which is elevated especially in Niemann Pick Type C. We can consider that a high LysoSM-509 level might be also an indicator of NCL, especially NCL type 3.

SLC35A2-CDG: novel variants with two ends of the spectrum.

OBJECTIVES: Congenital disorders of glycosylation (CDGs) are rare inherited metabolic disorders associated with facial dysmorphism and in the majority of the patients, there is an important neurological impairment. Epilepsy was a main concern in rare forms of the disease. There are two groups of the disease: CDG-I results from the defects in glycan addition to the N-terminal and CDG-II occurs due to defects in the processing of protein bound glycans. SLC35A2-CDG is a rare form of CDG caused by mutations in the X-linked gene that encodes a UDP-Galactose transporter. The manifestations of the disease include seizures, failure to thrive, delayed myelination, and cerebral atrophy. CASE PRESENTATION: We describe herein a severe female child with intractable seizures, microcephaly, growth retardation, hypotonia, global developmental delay, facial dysmorphism, skeletal findings, cerebral/cerebellar atrophy, and thin corpus callosum, and a mildly affected male carrying a novel variant with seizures and mild global developmental delay who were found by whole exome sequencing (WES) for SLC35A2 mutations previously not reported. CONCLUSIONS: Our findings expand the number of reported cases and add novel variants to the repertoire of SLC35A2-CDG.