@article {957, title = {Multiomic analysis elucidates Complex I deficiency caused by a deep intronic variant in NDUFB10.}, journal = {Hum Mutat}, volume = {42}, year = {2021}, month = {2021 Jan}, pages = {19-24}, abstract = {

The diagnosis of Mendelian disorders following uninformative exome and genome sequencing remains a challenging and often unmet need. Following uninformative exome and genome sequencing of a family quartet including two siblings with suspected mitochondrial disorder, RNA sequencing (RNAseq) was pursued in one sibling. Long-read amplicon sequencing was used to determine and quantify transcript structure. Immunoblotting studies and quantitative proteomics were performed to demonstrate functional impact. Differential expression analysis of RNAseq data identified significantly decreased expression of the mitochondrial OXPHOS Complex I subunit NDUFB10 associated with a cryptic exon in intron 1 of NDUFB10, that included an in-frame stop codon. The cryptic exon contained a rare intronic variant that was homozygous in both affected siblings. Immunoblot and quantitative proteomic analysis of fibroblasts revealed decreased abundance of Complex I subunits, providing evidence of isolated Complex I deficiency. Through multiomic analysis we present data implicating a deep intronic variant in NDUFB10 as the cause of mitochondrial disease in two individuals, providing further support of the gene-disease association. This study highlights the importance of transcriptomic and proteomic analyses as complementary diagnostic tools in patients undergoing genome-wide diagnostic evaluation.

}, issn = {1098-1004}, doi = {10.1002/humu.24135}, author = {Helman, Guy and Compton, Alison G and Hock, Daniella H and Walkiewicz, Marzena and Brett, Gemma R and Pais, Lynn and Tan, Tiong Y and De Paoli-Iseppi, Ricardo and Clark, Michael B and Christodoulou, John and White, Susan M and Thorburn, David R and Stroud, David A and Stark, Zornitza and Simons, Cas} } @article {949, title = {A relatively common homozygous TRAPPC4 splicing variant is associated with an early-infantile neurodegenerative syndrome.}, journal = {Eur J Hum Genet}, volume = {29}, year = {2021}, month = {2021 Feb}, pages = {271-279}, abstract = {

Trafficking protein particle (TRAPP) complexes, which include the TRAPPC4 protein, regulate membrane trafficking between lipid organelles in a process termed vesicular tethering. TRAPPC4 was recently implicated in a recessive neurodevelopmental condition in four unrelated families due to a shared c.454+3A>G splice variant. Here, we report 23 patients from 17 independent families with an early-infantile-onset neurodegenerative presentation, where we also identified the homozygous variant hg38:11:119020256 A>G (NM_016146.5:c.454+3A>G) in TRAPPC4 through exome or genome sequencing. No other clinically relevant TRAPPC4 variants were identified among any of over 10,000 patients with neurodevelopmental conditions. We found the carrier frequency of TRAPPC4 c.454+3A>G was 2.4-5.4 per 10,000 healthy individuals. Affected individuals with the homozygous TRAPPC4 c.454+3A>G variant showed profound psychomotor delay, developmental regression, early-onset epilepsy, microcephaly and progressive spastic tetraplegia. Based upon RNA sequencing, the variant resulted in partial exon 3 skipping and generation of an aberrant transcript owing to use of a downstream cryptic splice donor site, predicting a premature stop codon and nonsense mediated decay. These data confirm the pathogenicity of the TRAPPC4 c.454+3A>G variant, and refine the clinical presentation of TRAPPC4-related encephalopathy.

}, issn = {1476-5438}, doi = {10.1038/s41431-020-00717-5}, author = {Ghosh, Shereen G and Scala, Marcello and Beetz, Christian and Helman, Guy and Stanley, Valentina and Yang, Xiaoxu and Breuss, Martin W and Mazaheri, Neda and Selim, Laila and Hadipour, Fatemeh and Pais, Lynn and Stutterd, Chloe A and Karageorgou, Vasiliki and Begtrup, Amber and Crunk, Amy and Juusola, Jane and Willaert, Rebecca and Flore, Leigh A and Kennelly, Kelly and Spencer, Christopher and Brown, Martha and Trapane, Pamela and Hurst, Anna C E and Lane Rutledge, S and Goodloe, Dana H and McDonald, Marie T and Shashi, Vandana and Schoch, Kelly and Tomoum, Hoda and Zaitoun, Raghda and Hadipour, Zahra and Galehdari, Hamid and Pagnamenta, Alistair T and Mojarrad, Majid and Sedaghat, Alireza and Dias, Patr{\'\i}cia and Quintas, Sofia and Eslahi, Atiyeh and Shariati, Gholamreza and Bauer, Peter and Simons, Cas and Houlden, Henry and Issa, Mahmoud Y and Zaki, MAH S and Maroofian, Reza and Gleeson, Joseph G} } @article {970, title = {A mutation affecting laminin alpha 5 polymerisation gives rise to a syndromic developmental disorder.}, journal = {Development}, volume = {147}, year = {2020}, month = {2020 06 22}, abstract = {

Laminin alpha 5 (LAMA5) is a member of a large family of proteins that trimerise and then polymerise to form a central component of all basement membranes. Consequently, the protein plays an instrumental role in shaping the normal development of the kidney, skin, neural tube, lung and limb, and many other organs and tissues. Pathogenic mutations in some laminins have been shown to cause a range of largely syndromic conditions affecting the competency of the basement membranes to which they contribute. We report the identification of a mutation in the polymerisation domain of LAMA5 in a patient with a complex syndromic disease characterised by defects in kidney, craniofacial and limb development, and by a range of other congenital defects. Using CRISPR-generated mouse models and biochemical assays, we demonstrate the pathogenicity of this variant, showing that the change results in a failure of the polymerisation of α/β/γ laminin trimers. Comparing these phenotypes with those apparent upon gene deletion in mice provides insights into the specific functional importance of laminin polymerisation during development and tissue homeostasis.

}, keywords = {Amino Acid Sequence, Animals, Animals, Newborn, Child, Preschool, Developmental Disabilities, Fetal Development, Fetus, Humans, Hydronephrosis, Infant, Newborn, Kidney, Laminin, Lung, Male, Mice, Mutation, Polymerization, Protein Domains, Syndrome}, issn = {1477-9129}, doi = {10.1242/dev.189183}, author = {Jones, Lynelle K and Lam, Rachel and McKee, Karen K and Aleksandrova, Maya and Dowling, John and Alexander, Stephen I and Mallawaarachchi, Amali and Cottle, Denny L and Short, Kieran M and Pais, Lynn and Miner, Jeffery H and Mallett, Andrew J and Simons, Cas and McCarthy, Hugh and Yurchenco, Peter D and Smyth, Ian M} } @article {582, title = {Cerebral hypomyelination associated with biallelic variants of FIG4.}, journal = {Hum Mutat}, volume = {40}, year = {2019}, month = {2019 05}, pages = {619-630}, abstract = {

The lipid phosphatase gene FIG4 is responsible for Yunis-Var{\'o}n syndrome and Charcot-Marie-Tooth disease Type 4J, a peripheral neuropathy. We now describe four families with FIG4 variants and prominent abnormalities of central nervous system (CNS) white matter (leukoencephalopathy), with onset in early childhood, ranging from severe hypomyelination to mild undermyelination, in addition to peripheral neuropathy. Affected individuals inherited biallelic FIG4 variants from heterozygous parents. Cultured fibroblasts exhibit enlarged vacuoles characteristic of FIG4 dysfunction. Two unrelated families segregate the same G > A variant in the +1 position of intron 21 in the homozygous state in one family and compound heterozygous in the other. This mutation in the splice donor site of exon 21 results in read-through from exon 20 into intron 20 and truncation of the final 115 C-terminal amino acids of FIG4, with retention of partial function. The observed CNS white matter disorder in these families is consistent with the myelination defects in the FIG4 null mouse and the known role of FIG4 in oligodendrocyte maturation. The families described here the expanded clinical spectrum of FIG4 deficiency to include leukoencephalopathy.

}, issn = {1098-1004}, doi = {10.1002/humu.23720}, author = {Lenk, Guy M and Berry, Ian R and Stutterd, Chloe A and Blyth, Moira and Green, Lydia and Vadlamani, Gayatri and Warren, Daniel and Craven, Ian and Fanjul-Fernandez, Miriam and Rodriguez-Casero, Victoria and Lockhart, Paul J and Vanderver, Adeline and Simons, Cas and Gibb, Susan and Sadedin, Simon and White, Susan M and Christodoulou, John and Skibina, Olga and Ruddle, Jonathan and Tan, Tiong Y and Leventer, Richard J and Livingston, John H and Meisler, Miriam H} }