Atypical free sialic acid storage disorder associated with tissue specific mosaicism of SLC17A5.

Free sialic acid storage disorder (FSASD) is a rare autosomal recessive lysosomal storage disease caused by pathogenic SLC17A5 variants with variable disease severity. We performed a multidisciplinary evaluation of an adolescent female with suspected lysosomal storage disease and conducted comprehensive studies to uncover the molecular etiology. The proband exhibited intellectual disability, a storage disease gestalt, and mildly elevated urine free sialic acid levels.

Structural variant allelic heterogeneity in MECP2 duplication syndrome provides insight into clinical severity and variability of disease expression.

Background: MECP2 Duplication Syndrome, also known as X-linked intellectual developmental disorder Lubs type (MRXSL; MIM: 300260), is a neurodevelopmental disorder caused by copy number gains spanning MECP2. Despite varying genomic rearrangement structures, including duplications and triplications, and a wide range of duplication sizes, no clear correlation exists between DNA rearrangement and clinical features. We had previously demonstrated that up to 38% of MRXSL families are characterized by complex genomic rearrangements (CGRs) of intermediate complexity (2 ≤ copy number variant breakpoints < 5), yet the impact of these genomic structures on regulation of gene expression and phenotypic manifestations have not been investigated.

The characterization of new de novo CACNA1G variants affecting the intracellular gate of Cav3.1 channel broadens the spectrum of neurodevelopmental phenotypes in SCA42ND.

Purpose: Missense de novo variants in CACNA1G, which encodes the Cav3.1 T-type calcium channel, have been associated with a severe, early-onset form of cerebellar disorder with neurodevelopmental deficits (SCA42ND). We explored a large series of pediatric cases carrying heterozygous variants in CACNA1G to further characterize genotype-phenotype correlations in SCA42ND.

The DESSH Clinic: A New Multidisciplinary Clinic to Address the Complex Needs of Individuals with a Rare Genetic Disorder.

DeSanto-Shinawi (DESSH) syndrome is a rare autosomal dominant condition caused by pathogenic variants in the WAC gene. DESSH syndrome was first identified in 2015 in six patients, but has since been diagnosed in more than 200 individuals worldwide. Patients exhibit a variable degree of developmental delay (DD), intellectual disability (ID), hypotonia, gastrointestinal and eye abnormalities, epilepsy, behavioral difficulties, and recognizable facial features.

Child Neurology: Five-Year Update on Siblings With Riboflavin Transporter Deficiency: Stable Visual and Neurologic Status With Continued Riboflavin Therapy.

Riboflavin transporter deficiency (RTD), previously referred to as Brown-Vialetto-Van Laere syndrome, is caused by pathogenic variants in the , , or genes, resulting in RTD types 1, 2, and 3, respectively. Researchers estimate an occurrence of approximately 1 in 1,000,000. There is only one case of type 1 described in medical literature.