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Du J, Li L, Fu D. Whole-exome-based single nucleotide variants and copy number analysis for prenatal diagnosis of compound heterozygosity of SMPD4. Psychiatr Genet 2024; 34:74-80. [PMID: 38690959 DOI: 10.1097/ypg.0000000000000369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
BACKGROUND Biallelic loss-of-function variants in SMPD4 cause a rare and severe neurodevelopmental disorder. These variants have been identified in a group of children with neurodevelopmental disorders with microcephaly, arthrogryposis, and structural brain anomalies. SMPD4 encodes a sphingomyelinase that hydrolyzes sphingomyelin into ceramide at neutral pH and can thereby affect membrane lipid homeostasis. SMPD4 localizes to the membranes of the endoplasmic reticulum and nuclear envelope and interacts with nuclear pore complexes. MATERIALS AND METHODS For the efficient prenatal diagnosis of rare and undiagnosed diseases, the parallel detection of copy number variants (CNVs) and single nucleotide variants using whole-exome analysis is required. A physical examination of the parents was performed. Karyotype and whole-exome analysis were performed for the fetus and the parents. RESULTS A fetus with microcephaly and arthrogryposis; biallelic null variants (c.387-1G>A; Chr2[GRCh38]: g.130142742_130202459del) were detected by whole-exome sequencing (WES). We have reported for the first time the biallelic loss-of-function mutations in SMPD4 in patients born to unrelated parents in China. CONCLUSION WES could replace chromosomal microarray analysis and copy number variation sequencing as a more cost-effective genetic test for detecting CNVs and diagnosing highly heterogeneous conditions.
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Affiliation(s)
| | - Lin Li
- Department of Ultrasound, Renmin Hospital, Hubei University of Medicine, Shiyan, People's Republic of China
| | - Dinghu Fu
- Department of Ultrasound, Renmin Hospital, Hubei University of Medicine, Shiyan, People's Republic of China
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Chen J, Landback P, Arsala D, Guzzetta A, Xia S, Atlas J, Sosa D, Zhang YE, Cheng J, Shen B, Long M. Evolutionarily new genes in humans with disease phenotypes reveal functional enrichment patterns shaped by adaptive innovation and sexual selection. bioRxiv 2024:2023.11.14.567139. [PMID: 38045239 PMCID: PMC10690195 DOI: 10.1101/2023.11.14.567139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
New genes (or young genes) are genetic novelties pivotal in mammalian evolution. Their phenotypic impacts and evolutionary pattern over time, however, remain elusive in humans due to the technical and ethical complexities in functional studies. By combining human gene age dating and Mendelian disease phenotyping, our research reveals a gradual increase in disease gene proportions with gene age. Logistic regression modeling indicates that this increase could be related to longer protein lengths and higher burdens of deleterious de novo germline variants (DNVs) for older genes. We also find a steady integration of new genes with biomedical phenotypes into the human genome over macroevolutionary timescales (~0.07% per million years). Despite this stable pace, we observe distinct patterns in phenotypic enrichment, pleiotropy, and selective pressures across gene ages. Notably, young genes show significant enrichment in diseases related to the male reproductive system, indicating strong sexual selection. Young genes also exhibit disease-related functions in tissues and systems potentially linked to human phenotypic innovations, such as increased brain size, musculoskeletal phenotypes, and color vision. We further reveal a logistic growth pattern of pleiotropy over evolutionary time, indicating a diminishing marginal growth of new functions for older genes due to intensifying selective constraints over time. We propose a "pleiotropy-barrier" model that delineates higher potentials of phenotypic innovation for young genes than for older genes, a process subject to natural selection. Our study demonstrates that evolutionary new genes are critical in influencing human reproductive evolution and adaptive phenotypic innovations driven by sexual and natural selection, with low pleiotropy as a selective advantage.
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Affiliation(s)
- Jianhai Chen
- Department of Ecology and Evolution, The University of Chicago, 1101 E 57th Street, Chicago, IL 60637
- Institutes for Systems Genetics, West China University Hospital, Chengdu 610041, China
| | - Patrick Landback
- Department of Ecology and Evolution, The University of Chicago, 1101 E 57th Street, Chicago, IL 60637
| | - Deanna Arsala
- Department of Ecology and Evolution, The University of Chicago, 1101 E 57th Street, Chicago, IL 60637
| | - Alexander Guzzetta
- Department of Pathology, The University of Chicago, 1101 E 57th Street, Chicago, IL 60637
| | - Shengqian Xia
- Department of Ecology and Evolution, The University of Chicago, 1101 E 57th Street, Chicago, IL 60637
| | - Jared Atlas
- Department of Ecology and Evolution, The University of Chicago, 1101 E 57th Street, Chicago, IL 60637
| | - Dylan Sosa
- Department of Ecology and Evolution, The University of Chicago, 1101 E 57th Street, Chicago, IL 60637
| | - Yong E. Zhang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jingqiu Cheng
- Institutes for Systems Genetics, West China University Hospital, Chengdu 610041, China
| | - Bairong Shen
- Institutes for Systems Genetics, West China University Hospital, Chengdu 610041, China
| | - Manyuan Long
- Department of Ecology and Evolution, The University of Chicago, 1101 E 57th Street, Chicago, IL 60637
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Aoki S, Watanabe K, Kato M, Konishi Y, Kubota K, Kobayashi E, Nakashima M, Saitsu H. Two novel cases of biallelic SMPD4 variants with brain structural abnormalities. Neurogenetics 2024; 25:3-11. [PMID: 37882972 DOI: 10.1007/s10048-023-00737-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 10/14/2023] [Indexed: 10/27/2023]
Abstract
Sphingomyelin phosphodiesterase 4 (SMPD4) encodes a member of the Mg2+-dependent, neutral sphingomyelinase family that catalyzes the hydrolysis of the phosphodiester bond of sphingomyelin to form phosphorylcholine and ceramide. Recent studies have revealed that biallelic loss-of-function variants of SMPD4 cause syndromic neurodevelopmental disorders characterized by microcephaly, congenital arthrogryposis, and structural brain anomalies. In this study, three novel loss-of-function SMPD4 variants were identified using exome sequencing (ES) in two independent patients with developmental delays, microcephaly, seizures, and brain structural abnormalities. Patient 1 had a homozygous c.740_741del, p.(Val247Glufs*21) variant and showed profound intellectual disability, hepatomegaly, a simplified gyral pattern, and a thin corpus callosum without congenital dysmorphic features. Patient 2 had a compound heterozygous nonsense c.2124_2125del, p.(Phe709*) variant and splice site c.1188+2dup variant. RNA analysis revealed that the c.1188+2dup variant caused exon 13 skipping, leading to a frameshift (p.Ala406Ser*6). In vitro transcription analysis using minigene system suggested that mRNA transcribed from mutant allele may be degraded by nonsense-mediated mRNA decay system. He exhibited diverse manifestations, including growth defects, muscle hypotonia, respiratory distress, arthrogryposis, insulin-dependent diabetes mellitus, sensorineural hearing loss, facial dysmorphism, and various brain abnormalities, including cerebral atrophy, hypomyelination, and cerebellar hypoplasia. Here, we review previous literatures and discuss the phenotypic diversity of SMPD4-related disorders.
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Affiliation(s)
- Shintaro Aoki
- Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
- Advanced Research Facilities & Services, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Kazuki Watanabe
- Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan
| | - Yukihiko Konishi
- Department of Pediatrics, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Kazuo Kubota
- Department of Pediatrics, Gifu University Graduate School of Medicine, Gifu, Japan
- Division of Clinical Genetics, Gifu University Hospital, Gifu, Japan
| | - Emiko Kobayashi
- Department of Pediatrics, Gifu Prefectural General Medical Center, Gifu, Japan
| | - Mitsuko Nakashima
- Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan.
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan.
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Inskeep KA, Crase B, Stottmann RW. SMPD4 mediated sphingolipid metabolism regulates brain and primary cilia development. bioRxiv 2023:2023.12.15.571873. [PMID: 38168190 PMCID: PMC10760124 DOI: 10.1101/2023.12.15.571873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Genetic variants in multiple sphingolipid biosynthesis genes cause human brain disorders. A recent study collected patients from twelve unrelated families with variants in the gene SMPD4 , a neutral sphingomyelinase which metabolizes sphingomyelin into ceramide at an early stage of the biosynthesis pathway. These patients have severe developmental brain malformations including microcephaly and cerebellar hypoplasia. However, the mechanism of SMPD4 was not known and we pursued a new mouse model. We hypothesized that the role of SMPD4 in producing ceramide is important for making primary cilia, a crucial organelle mediating cellular signaling. We found that the mouse model has cerebellar hypoplasia due to failure of Purkinje cell development. Human induced pluripotent stem cells exhibit neural progenitor cell death and have shortened primary cilia which is rescued by adding exogenous ceramide. SMPD4 production of ceramide is crucial for human brain development.
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Chen J. Evolutionarily new genes in humans with disease phenotypes reveal functional enrichment patterns shaped by adaptive innovation and sexual selection. Res Sq 2023:rs.3.rs-3632644. [PMID: 38045389 PMCID: PMC10690325 DOI: 10.21203/rs.3.rs-3632644/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
New genes (or young genes) are structural novelties pivotal in mammalian evolution. Their phenotypic impact on humans, however, remains elusive due to the technical and ethical complexities in functional studies. Through combining gene age dating with Mendelian disease phenotyping, our research reveals that new genes associated with disease phenotypes steadily integrate into the human genome at a rate of ~ 0.07% every million years over macroevolutionary timescales. Despite this stable pace, we observe distinct patterns in phenotypic enrichment, pleiotropy, and selective pressures between young and old genes. Notably, young genes show significant enrichment in the male reproductive system, indicating strong sexual selection. Young genes also exhibit functions in tissues and systems potentially linked to human phenotypic innovations, such as increased brain size, bipedal locomotion, and color vision. Our findings further reveal increasing levels of pleiotropy over evolutionary time, which accompanies stronger selective constraints. We propose a "pleiotropy-barrier" model that delineates different potentials for phenotypic innovation between young and older genes subject to natural selection. Our study demonstrates that evolutionary new genes are critical in influencing human reproductive evolution and adaptive phenotypic innovations driven by sexual and natural selection, with low pleiotropy as a selective advantage.
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Abstract
The cerebral cortex is the brain's outermost layer. It is responsible for processing motor and sensory information that support high-level cognitive abilities and shape personality. Its development and functional organization strongly rely on cell communication that is established via an intricate system of diffusible signals and physical contacts during development. Interfering with this cellular crosstalk can cause neurodevelopmental disorders. Here, we review how crosstalk between migrating cells and their environment influences cerebral cortex development, ranging from neurogenesis to synaptogenesis and assembly of cortical circuits.
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Affiliation(s)
- Julie Stoufflet
- Laboratory of Molecular Regulation of Neurogenesis, GIGA-Stem Cells and GIGA-Neurosciences, Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège, CHU Sart Tilman, Liège 4000, Belgium
| | - Sylvia Tielens
- Laboratory of Molecular Regulation of Neurogenesis, GIGA-Stem Cells and GIGA-Neurosciences, Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège, CHU Sart Tilman, Liège 4000, Belgium
| | - Laurent Nguyen
- Laboratory of Molecular Regulation of Neurogenesis, GIGA-Stem Cells and GIGA-Neurosciences, Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège, CHU Sart Tilman, Liège 4000, Belgium; Walloon Excellence in Life Sciences and Biotechnology (WELBIO), Wavres, Belgium.
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