... and another! Fly study helps point to possible genetic cause of an ARID

Kazeminasab S, Taskiran II, Fattahi Z, Bazazzadegan N, Hosseini M, Rahimi M, Oladnabi M, Haddadi M, Celik A, Ropers HH, Najmabadi H, Kahrizi K. CNKSR1 gene defect can cause syndromic autosomal recessive intellectual disability. Am J Med Genet B Neuropsychiatr Genet. 2018 Nov 18. doi: 10.1002/ajmg.b.32648. PMID: 30450701.

From the abstract: "... A novel frameshift mutation in CNKSR1 gene was detected by Next-Generation Sequencing (NGS) in an Iranian family with syndromic autosomal recessive intellectual disability (ARID). CNKSR1 encodes a connector enhancer of kinase suppressor of Ras 1 ... CNKSR1 interacts with proteins which have already been shown to be associated with intellectual disability (ID) in the MAPK signaling pathway and promotes cell migration through RhoA-mediated c-Jun N-terminal kinase (JNK) activation. Lack of CNKSR1 transcripts and protein was observed in lymphoblastoid cells derived from affected patients using qRT-PCR and western blot analysis ...  RNAi-mediated knockdown of cnk, the CNKSR1 orthologue in Drosophila melanogaster brain, led to defects in eye and mushroom body (MB) structures. In conclusion, our findings support the possible role of CNKSR1 in brain development which can lead to cognitive impairment."

Drosophila studies contributed to -- another -- study that identifies a human disease gene

Ansar M, Chung HL, Taylor RL, Nazir A, Imtiaz S, Sarwar MT, Manousopoulou A, Makrythanasis P, Saeed S, Falconnet E, Guipponi M, Pournaras CJ, Ansari MA, Ranza E, Santoni FA, Ahmed J, Shah I, Gul K, Black GC, Bellen HJ, Antonarakis SE. Bi-allelic Loss-of-Function Variants in DNMBP Cause Infantile Cataracts. Am J Hum Genet. 2018 Oct 4;103(4):568-578. PMID: 30290152; PMCID: PMC6174361.

From the abstract: "Infantile and childhood-onset cataracts form a heterogeneous group of disorders; among the many genetic causes, numerous pathogenic variants in additional genes associated with autosomal-recessive infantile cataracts remain to be discovered. We identified three consanguineous families affected by bilateral infantile cataracts. Using exome sequencing, we found homozygous loss-of-function variants in DNMBP ... The phenotypes of all affected individuals include infantile-onset cataracts. RNAi-mediated knockdown of the Drosophila ortholog still life (sif), enriched in lens-secreting cells, affects the development of these cells as well as the localization of E-cadherin, alters the distribution of septate junctions in adjacent cone cells, and leads to a ∼50% reduction in electroretinography amplitudes in young flies. ... We therefore conclude that DNMBP loss-of-function variants cause infantile-onset cataracts in humans."

Big thank you to the US NIH Office of Research Infrastructure Programs (ORIP) for support of projects that generated fly stocks and other resources used in this study.

Drosophila studies help identify mutations in NUS1 as contributors to Parkinson's Disease

Guo JF, Zhang L, Li K, Mei JP, Xue J, Chen J, Tang X, Shen L, Jiang H, Chen C, Guo H, Wu XL, Sun SL, Xu Q, Sun QY, Chan P, Shang HF, Wang T, Zhao GH, Liu JY, Xie XF, Jiang YQ, Liu ZH, Zhao YW, Zhu ZB, Li JD, Hu ZM, Yan XX, Fang XD, Wang GH, Zhang FY, Xia K, Liu CY, Zhu XW, Yue ZY, Li SC, Cai HB, Zhang ZH, Duan RH, Tang BS. Coding mutations in NUS1 contribute to Parkinson's disease. Proc Natl Acad Sci U S A. 2018 Oct 22. pii: 201809969. PMID: 30348779.

The abstract: "Whole-exome sequencing has been successful in identifying genetic factors contributing to familial or sporadic Parkinson's disease (PD). However, this approach has not been applied to explore the impact of de novo mutations on PD pathogenesis. Here, we sequenced the exomes of 39 early onset patients, their parents, and 20 unaffected siblings to investigate the effects of de novo mutations on PD. We identified 12 genes with de novo mutations (MAD1L1, NUP98, PPP2CB, PKMYT1, TRIM24, CEP131, CTTNBP2, NUS1, SMPD3, MGRN1, IFI35, and RUSC2), which could be functionally relevant to PD pathogenesis. Further analyses of two independent case-control cohorts (1,852 patients and 1,565 controls in one cohort and 3,237 patients and 2,858 controls in the other) revealed that NUS1 harbors significantly more rare nonsynonymous variants (P = 1.01E-5, odds ratio = 11.3) in PD patients than in controls. Functional studies in Drosophila demonstrated that the loss of NUS1 could reduce the climbing ability, dopamine level, and number of dopaminergic neurons in 30-day-old flies and could induce apoptosis in fly brain. Together, our data suggest that de novo mutations could contribute to early onset PD pathogenesis and identify NUS1 as a candidate gene for PD."

Drosophila research studies contribute to patient diagnosis for patients with previously undiagnosed diseases

Splinter et al. Effect of Genetic Diagnosis on Patients with Previously Undiagnosed Disease. New England Journal of Medicine. DOI: 10.1056/NEJMoa1714458

This article, which can be accessed free at NEJM, includes a description of how studies in Drosophila and other model systems contribute to identification by the Undiagnosed Diseases Network of disease-causing variants in genome data from previously undiagnosed patients. As stated in the article, "The model organisms screening center was directly involved in the diagnosis of eight patients in this study."

Potential lung cancer treatment identified using flies advances to clinical trial

A potential lung chancer treatment identified using flies is entering a clinical trial stage. View a post at the drosophilaresearch.org website with links to the original study.

Cross-species study to identify modifiers of alpha-synuclein levels

Rousseaux MWC, Vázquez-Vélez GE, Al-Ramahi I, Jeong HH, Bajic A, Revelli JP, Ye H, Phan ET, Deger JM, Perez AM, Kim JY, Lavery LA, Xu Q, Li MZ, Kang H, Kim JJ, Shulman JM, Westbrook TF, Elledge SJ, Liu Z, Botas J, Zoghbi HY. A druggable genome screen identifies modifiers of α-synuclein levels via a tiered cross-species validation approach. J Neurosci. 2018 Sep 24. pii: 0254-18. PMID: 30249792.

From the abstract: "Accumulation of α-Synuclein (α-Syn) causes Parkinson's disease (PD) as well as other synucleopathies. ... increased α-Syn levels are intrinsically tied to PD pathogenesis and underscore the importance of identifying the factors that regulate its levels. In this study, we establish a pooled RNAi screening approach and validation pipeline to probe the druggable genome for modifiers of α-Syn levels and identify 60 promising targets. Using a cross-species, tiered validation approach, we validate six strong candidates that modulate α-Syn levels and toxicity in cell lines, Drosophila, human neurons and mouse brain of both sexes. ... This approach has broad applicability to the multitude of neurological diseases that are caused by mutations in genes whose dosage is critical for brain function."

Results from a fly genetic screen implicate a long non-coding RNA in Charcot-Marie-Tooth disease

Muraoka Y, Nakamura A, Tanaka R, Suda K, Azuma Y, Kushimura Y, Piccolo LL, Yoshida H, Mizuta I, Tokuda T, Mizuno T, Nakagawa M, Yamaguchi M. Genetic screening of the genes interacting with Drosophila FIG4 identified a novel link between CMT-causing gene and long noncoding RNAs. Exp Neurol. 2018 Aug 27. pii: S0014-4886(18)30377-7. PMID: 30165075.

From the abstract: "Neuron-specific knockdown of the dFIG4 gene, a Drosophila homologue of human FIG4 and one of the causative genes for Charcot-Marie-Tooth disease (CMT), reduces the locomotive abilities of adult flies, as well as causing defects at neuromuscular junctions ... By genetic screening, we detected 9 and 15 chromosomal regions whose deletions either suppressed or enhanced the rough eye phenotype induced by the dFIG4 knockdown. By further genetic screening ... we identified the gene CR18854 that suppressed the rough eye phenotype and the loss-of-cone cell phenotype. The CR18854 gene encodes a long non-coding RNA (lncRNA) consisting of 2566 bases. ... We also obtained data indicating genetic interaction between CR18854 and Cabeza, a Drosophila homologue of human FUS, which is one of the causing genes for amyotrophic lateral sclerosis (ALS). These results suggest that lncRNAs such as CR18854 and hsrω are involved in a common pathway in CMT and ALS pathogenesis."