You will be shown a question, followed by excerpts from biomedical research papers. Please answer the question based on the provided context. Do not include any text in your response other than the answer.

Question: Describe Full Spectrum of Intolerance to Loss-of-function (FUSIL)

Context: The identification of causal variants in sequencing studies remains a considerable challenge that can be partially addressed by new gene-specific knowledge. Here, we integrate measures of how essential a gene is to supporting life, as inferred from viability and phenotyping screens performed on knockout mice by the International Mouse Phenotyping Consortium and essentiality screens carried out on human cell lines. We propose a cross-species gene classification across the Full Spectrum of Intolerance to Loss-of-function (FUSIL) and demonstrate that genes in five mutually exclusive FUSIL categories have differing biological properties. Most notably, Mendelian disease genes, particularly those associated with developmental disorders, are highly overrepresented among genes non-essential for cell survival but required for organism development. After screening developmental disorder cases from three independent disease sequencing consortia, we identify potentially pathogenic variants in genes not previously associated with rare diseases. We therefore propose FUSIL as an efficient approach for disease gene discovery.
Full Spectrum of Intolerance to Loss-of-function (FUSIL) is a cross-species gene classification across the full spectrum of mutations in genes of unknown function. FUSIL has been proposed as a method to identify potentially pathogenic variants in genes not previously associated with rare diseases. The identification of causal variants in sequencing studies remains a considerable challenge that can be partially addressed by new gene-specific knowledge. By integrating measures of how essential a gene is to supporting life, as inferred from viability and phenotyping screens performed on knockout mice by the International Mouse Phenotyping Consortium and essentiality screens carried out on human cell lines, a cross-species gene classification across the Full Spectrum of Intolerance to Loss-of-function (FUSIL) was proposed. Genes in five mutually exclusive FUSIL categories have differing biological properties. Most notably, Mendelian disease genes, particularly those associated with developmental disorders, are highly overrepresented among genes non-essential for cell survival but required for organism development. The FUSIL is the Full Spectrum of Intolerance to Loss-of-function (FUSIL). It's the full spectrum of genes that are not essential for cell survival, but essential for organism development. Full Spectrum of Intolerance to Loss-of-function (FUSIL) is a cross-species gene classification across the full spectrum of genes in five mutually exclusive categories have differing biological properties. FUSIL is proposed as an efficient approach for disease gene discovery. Full Spectrum of Intolerance to Loss-of-function (FUSIL) is a cross-species gene classification across the full spectrum of essential and non-essential genes. FUSIL is an efficient approach for disease gene discovery.