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Background: Hereditary spastic paraplegias (HSP), a group of genetically heterogeneous neurological disorders with more than 56 documented loci (SPG1-56), are described either as uncomplicated (or pure), or complicated where in addition to spasticity and weakness of lower extremeties, additional neurological symptoms are present, including dementia, loss of vision, epilepsy, mental retardation and ichthyosis. We identified a large consanguineous family of Indian descent with four affected members with childhood onset HSP (SPG54), presenting with upper and lower limb spasticity, mental retardation and agenesis of the corpus callosum. Results: A common region of homozygosity on chromosome 8 spanning seven megabases (Mb) was identified in the affected individuals using the Illumina human cytoSNP-12 DNA Analysis BeadChip Kit. Exome sequencing identified a homozygous stop gain mutation (pR287X) in the phospholipase A, gene DDHD2, in the affected individuals, resulting in a premature stop codon and a severely truncated protein lacking the SAM and DDHD domains crucial for phosphoinositide binding and phospholipase activity. Conclusion: This mutation adds to the knowledge of HSP, suggests a possible founder effect for the pR287X mutation, and adds to the list of genes involved in lipid metabolism with a role in HSP and other neurodegenerative disorders. [ABSTRACT FROM AUTHOR]

Background: Congenital generalized lipodystrophy (CGL) also known as Berardinelli-Seip Congenital Lipodystrophy (BSCL) is a genetically heterogeneous disorder characterized by loss of adipose tissues, Acanthosis nigricans, diabetes mellitus, muscular hypertrophy, hepatomegaly and hypertriglyceridemia. There are four subclinical phenotypes of CGL (CGL1-4) and mutations in four genes AGPAT2, BSCL2, CAV1 and PTRF have been assigned to each type. Methods: The study included clinical and molecular investigations of CGL disease in a consanguineous Pakistani family. For mutation screening all the coding exons including splice junctions of AGPAT2, BSCL2, CAV1 and PTRF genes were PCR amplified and sequenced directly using an automated DNA sequencer ABI3730. Results: Sequence analysis revealed a single base pair deletion mutation (c.636delC; p.Tyr213ThrfsX20) in exon 5 of BSCL2 gene causing a frame shift and premature termination codon. Conclusion: Mutation identified here in BSCL2 gene causing congenital generalized lipodystrophy is the first report in Pakistani population. The patients exhibited characteristic features of generalized lipodystrophy, Acanthosis nigricans, diabetes mellitus and hypertrophic cardiomyopathy. [ABSTRACT FROM AUTHOR]