Calcyphosine-like (CAPSL) is regulated in Multiple Symmetric Lipomatosis and is involved in Adipogenesis.

Little is known on the causes and pathogenesis of the adipose tissue disorder (familial) Multiple Symmetric Lipomatosis (MSL). In a four-generation MSL-family, we performed whole exome sequencing (WES) in 3 affected individuals and 1 obligate carrier and identified Calcyphosine-like (CAPSL) as the most promising candidate gene for this family. Screening of 21 independent patients excluded CAPSL coding sequence variants as a common monogenic cause, but using immunohistochemistry we found that CAPSL was down-regulated in adipose tissue not only from the index patient but also in 10 independent sporadic MSL-patients. This suggests that CAPSL is regulated in sporadic MSL irrespective of the underlying genetic/multifactorial cause. Furthermore, we cultivated pre-adipocytes from MSL-patients and generated 3T3-L1-based Capsl knockout and overexpressing cell models showing altered autophagy, adipogenesis, lipogenesis and Sirtuin-1 (SIRT1) expression. CAPSL seems to be involved in adipocyte biology and perturbation of autophagy is a potential mechanism in the pathogenesis of MSL. Downregulation of CAPSL and upregulation of UCP1 were common features in MSL fat while the known MSL genes MFN2 and LIPE did not show consistent alterations. CAPSL immunostainings could serve as first diagnostic tools in MSL clinical care with a potential to improve time to diagnosis and healthcare options.

The Discovery of a LEMD2-Associated Nuclear Envelopathy with Early Progeroid Appearance Suggests Advanced Applications for AI-Driven Facial Phenotyping.

Over a relatively short period of time, the clinical geneticist's "toolbox" has been expanded by machine-learning algorithms for image analysis, which can be applied to the task of syndrome identification on the basis of facial photographs, but these technologies harbor potential beyond the recognition of established phenotypes. Here, we comprehensively characterized two individuals with a hitherto unknown genetic disorder caused by the same de novo mutation in LEMD2 (c.1436C>T;p.Ser479Phe), the gene which encodes the nuclear envelope protein LEM domain-containing protein 2 (LEMD2). Despite different ages and ethnic backgrounds, both individuals share a progeria-like facial phenotype and a distinct combination of physical and neurologic anomalies, such as growth retardation; hypoplastic jaws crowded with multiple supernumerary, yet unerupted, teeth; and cerebellar intention tremor. Immunofluorescence analyses of patient fibroblasts revealed mutation-induced disturbance of nuclear architecture, recapitulating previously published data in LEMD2-deficient cell lines, and additional experiments suggested mislocalization of mutant LEMD2 protein within the nuclear lamina. Computational analysis of facial features with two different deep neural networks showed phenotypic proximity to other nuclear envelopathies. One of the algorithms, when trained to recognize syndromic similarity (rather than specific syndromes) in an unsupervised approach, clustered both individuals closely together, providing hypothesis-free hints for a common genetic etiology. We show that a recurrent de novo mutation in LEMD2 causes a nuclear envelopathy whose prognosis in adolescence is relatively good in comparison to that of classical Hutchinson-Gilford progeria syndrome, and we suggest that the application of artificial intelligence to the analysis of patient images can facilitate the discovery of new genetic disorders.