The genetic basis of epidermolysis bullosa, a group of genetic disorders characterized by the mechanically induced formation of skin blisters, is largely known, but a number of cases still remain genetically unsolved. Here, we used whole-exome and targeted sequencing to identify monoallelic mutations, c.1A>G and c.2T>C, in the translation initiation codon of the gene encoding kelch-like protein 24 (KLHL24) in 14 individuals with a distinct skin-fragility phenotype and skin cleavage within basal keratinocytes. Remarkably, mutation c.1A>G occurred de novo and was recurrent in families originating from different countries. The striking similarities of the clinical features of the affected individuals point to a unique and very specific pathomechanism. We showed that mutations in the translation initiation codon of KLHL24 lead to the usage of a downstream translation initiation site with the same reading frame and formation of a truncated polypeptide. The pathobiology was examined in keratinocytes and fibroblasts of the affected individuals and via expression of mutant KLHL24, and we found mutant KLHL24 to be associated with abnormalities of intermediate filaments in keratinocytes and fibroblasts. In particular, KLHL24 mutations were associated with irregular and fragmented keratin 14. Recombinant overexpression of normal KLHL24 promoted keratin 14 degradation, whereas mutant KLHL24 showed less activity than the normal molecule. These findings identify KLHL24 mutations as a cause of skin fragility and identify a role for KLHL24 in maintaining the balance between intermediate filament stability and degradation required for skin integrity.

Long-term administration of caffeine in preterm infants is associated with an increase in oxygen consumption and with a reduction of weight gain. This may have implications for clinical practice as nutritional regimens need to be adjusted during this therapy.

The aim of the present study was to obtain serial values of O 2 consumption (V O 2 ), CO 2 production (V CO 2 ) and energy expenditure (EE) in healthy but extremely-low-birth-weight infants (birth weight , 1000 g), during the first 5 weeks after birth. A total of seventeen spontaneously breathing and appropriate-for-gestational-age (birth weight and body length above the 10th and below the 90th percentile) preterm infants with gestational age 25 -28 weeks and birth weight 590-990 g were enrolled in the study. Calorimetry was performed using an open-circuit calorimeter on days 6, 12, 18, 24, 30 and 36 of postnatal life. During the 5 weeks of observation, V O 2 increased from 4·7 (SD 0·5) to 9·1 (SD 1·0) ml/kg per min, V CO 2 from 4·5 (SD 0·4) to 8·3 (SD 0·6) ml/kg per min and EE from 115 (SD 12) to 310 (SD 71) kJ/kg per d. The energy intake was always higher than EE, even at days 6 and 12. The RER decreased from 0·99 (SD 0·09) at day 12 to 0·91 (SD 0·05) at day 30. On all study days, there were highly significant positive correlations between energy intake and weight gain, EE and weight gain, and EE and energy intake (P,0·05). Multiple regression analysis showed that on most study days EE was more affected by energy intake than by weight gain. We conclude that in healthy preterm infants with birth weight , 1000 g, EE increases by about 150 % in the first 5 weeks after birth, and that the EE values are related to energy intake and weight gain independent of postnatal age. Energy expenditure: Growth: Preterm: Oxygen consumptionThe substantial improvement of the survival rate in extremely-low-birth-weight (ELBW) infants (birth weight , 1000 g) has changed the focus towards prevention of long-term morbidity. Adequate nutrition is an important prerequisite for intact survival of ELBW infants (Lucas, 1987;Lucas et al. 2001). Determinations of energy requirements are usually based on calculation of the energy balance (= energy intake (EI) -energy loss via faeces and urineenergy expenditure (EE)). Energy loss via faeces and urine is about 10 % EI, independent of postnatal age and EI in preterm infants (Sauer et al. 1984a). However, EE tends to increase with increasing age. Chessex et al. (1981) suggested that EE increases with age of preterm infants due to increasing EI. Their assumption was based on only three serial studies in preterm infants with a mean birth weight of 1155 (SD 39) g. Leitch & Denne (2000) summarised published EE values measured in seventy-five preterm infants with birth weight , 1000 g v. postnatal age, and found an increase of EE from 209 kJ/kg per d at birth to 272 kJ/kg per d at 5 weeks of age. However, thirty-five of the seventy-five infants were small-for-gestational-age with a mean postnatal age of 6·0 weeks, whereas forty infants had birth weights appropriate for gestational age and mean postnatal age of 2·5 weeks. Thus, the apparent increase in EE with age may be due in part to higher EE of small-for-gestational-age infants (Boehler et al. 1999).Recommendations for EI and dietary intakes are ...

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