[Type 2 diabetes nephropathy: a thresholds complex trait and chromosomal morbid map]. / Nefropatía por diabetes mellitus tipo 2: un rasgo multifactorial con umbral y su mapa mórbido cromosómico.

Type 2 diabetes nephropathy is a multifactorial trait whose threshold or limit for the phenotypic expression depends on the additive effect of multiple loci and environmental factors that are specific to each population. After the sequencing of human genome more susceptibility loci through linkage studies and association have been found. The association studies showed involvement 69 loci, whereas genetic linkage studies involved 24 loci. Among environmental factors, genetically unknown foods and excessive consumption of beverages with sweeteners has been reported. However, despite wide evidence in the genetic component in the development of kidney damage, the environment participation is not evident in several perinatal studies. One of the approaches proposed given the genetic heterogeneity that influences nephropathy, are epistasis studies, which will become increasingly important in the upcoming years.

[The metabolic and molecular bases of Cockayne syndrome]. / Las bases metabólicas y moleculares del síndrome de Cockayne.

Cockayne is a segmental progeroid syndrome that has autosomal recessive inheritance pattern. It is mainly characterized by Intrauterine growth retardation, severe postnatal growth deficiency, cachectic dwarfism, microcephaly, wizened face, sensorineural hearing loss, cataracts, dental caries, cardiac arrhythmias, hypertension, atherosclerosis, proteinuria, micropenis, renal failure, skeletal abnormalities, skin photosensitivity, decreased subcutaneous adipose tissue, cerebral atrophy, dementia, basal ganglia calcifications, ataxia and apraxia. It has a complex phenotype given by genetic heterogeneity. There are five gene responsible for this syndrome: CSA, CSB, XPB, XPD and XPG, in which various mutations have been found. The biochemical effect of these mutations includes dysfunctional protein of the repair system for oxidative damage to DNA, the complex coupled to transcription and the nucleotide excision repair system. Considering the role played for these proteins and its effects on clinical phenotype when they are deficient, we suggest that these genes might be candidates for analyzing susceptibility to common chronic degenerative diseases related to oxidative stress and aging.