Systemic lupus erythematosus (SLE) is a complex autoimmune disease that causes substantial morbidity. As is typical for many other multifactorial disorders, much of the heritability of SLE remains unknown. We identified a rare autosomal recessive form of SLE, in which autozygome analysis revealed a null mutation in the DNASE1L3 gene. The DNASE1L3-related SLE we describe was always pediatric in onset and correlated with a high frequency of lupus nephritis. Our findings confirm the critical role of impaired clearance of degraded DNA in SLE pathogenesis.

The inherited osteolyses or 'vanishing bone' syndromes are a group of rare disorders of unknown etiology characterized by destruction and resorption of affected bones. The multicentric osteolyses are notable for interphalangeal joint erosions that mimic severe juvenile rheumatoid arthritis (OMIMs 166300, 259600, 259610 and 277950). We recently described an autosomal recessive form of multicentric osteolysis with carpal and tarsal resorption, crippling arthritic changes, marked osteoporosis, palmar and plantar subcutaneous nodules and distinctive facies in a number of consanguineous Saudi Arabian families. We localized the disease gene to 16q12-21 by using members of these families for a genome-wide search for homozygous-by-descent microsatellite markers. Haplotype analysis narrowed the critical region to a 1.2-cM region that spans the gene encoding MMP-2 (gelatinase A, collagenase type IV; (ref. 3). We detected no MMP2 enzymatic activity in the serum or fibroblasts of affected family members. We identified two family-specific homoallelic MMP2 mutations: R101H and Y244X. The nonsense mutation effects a deletion of the substrate-binding and catalytic sites and the fibronectin type II-like and hemopexin/TIMP2 binding domains. Based on molecular modeling, the missense mutation disrupts hydrogen bond formation within the highly conserved prodomain adjacent to the catalytic zinc ion.

LMNA encodes lamin A and lamin C, two major components of the nuclear lamina, and its pathogenic variants lead to a dozen distinct clinical entities collectively known as laminopathies. Most LMNA-related laminopathies are autosomal dominant but four are autosomal recessive; furthermore, some of the dominant variants have been associated with distinct phenotypes when inherited recessively, further complicating the ability to correlate genotype with phenotype. We report a consanguineous family in which the index presented with an apparently unique constellation of poikiloderma, joint motion restriction and distal acroosteolysis but lacks features of muscle weakness, lipodystrophy, or cardiac or craniofacial involvement. Molecular analysis revealed the presence of a novel homozygous LMNA missense variant (NM_170707.3:c.1774G4A; p.(Gly592Arg)) within an area of autozygome that is not shared by his unaffected siblings. The proposed causal link is further supported by in silico analysis of this variant. Our case suggests an expansion of LMNA allelic disorders to include distal acroosteolysis, poikiloderma and joint stiffness (DAPJ).

Background Familial Mediterranean fever is a hereditary inflammatory disorder caused by variants in MEFV. c.2230G>T p.(Ala744Ser) rs61732874 is considered to be an established pathogenic variant in MEFV, but in this study we provide a complete evaluation that suggests this variant is likely benign. Methods Using an in‐house exome database from 924 individuals, we extracted all individuals harboring this variant for clinical, laboratory, and familial evaluation. Results We identified the variant in 58 individuals from 39 families. The allele frequency of this variant in our database is 4.2%. None of the identified individuals match the diagnosis of Familial Mediterranean Fever. Using the American College of Medical Genetics and Genomics guidelines for variant classification, this variant is classified as likely benign and not pathogenic. Conclusion Conflicting evidence about variants creates challenges for testing laboratories and impacts patient care. Sharing information drawn mainly from underrepresented populations and clinical phenotyping are important tools for precise curation of genetic variants.