Exploring the Differences Between Dominant and Nondominant Feet and Hands Bone Mineral Density

The assessment of regional bone mineral density (BMD) has proved to be useful for illustrating the impact of focal bone demineralization diseases on bone mass. In these scenario, a common practice is to compare the affected limb with the contralateral limb. However, there are no studies comparing BMD differences between dominant vs nondominant limbs at these sites. In addition, most studies have assessed BMD in specific ROIs (regions of interests) instead of in the whole limb. The purpose of our study was to compare the BMD of dominant vs nondominant hands and feet in healthy individuals, using both the whole limb software and specific ROIs. We performed a cross-sectional analysis on untrained women and men over 18 years of age who volunteered to participate. BMD (g/cm²), bone area (cm²) and BMC (bone mineral content) (g) were measured by Lunar Prodigy DXA (GE Healthcare, Madison, WI, USA), using 2 different approaches: whole limb/region software and specific ROIs. A total of 42 subjects (11 men and 31 women) were included. Mean age was 44.19 ± 10.49 years. BMD was greater in the dominant in comparison with the nondominant hand. The difference was 0.014 (95% CI, 0.009-0.018) for the whole hand BMD, 0.023 (95% CI, 0.003-0.044) for ROI 1, and 0.016 (95% CI, 0.003-0.029) for ROI 2. No significant differences were found between dominant and nondominant foot BMD, using the whole limb software and specific ROIs. To our knowledge, this is the first study to explore the differences in BMD, bone area and BMC in terms of limb dominance, supporting the usefulness of DXA as an accurate and objective complementary diagnostic or follow-up tool in focal bone demineralization diseases.

Neonatal dopa-responsive extrapyramidal syndrome in twins with recessive GTPCH deficiency

The authors report two twin sisters, age 15 years, with recessive GTP cyclohydrolase deficiency, who presented with neonatal onset of rigidity, tremor, and dystonia but with no other symptoms suggestive of a diffuse CNS involvement. The plasma phenylalanine levels were normal. Treatment with L-dopa/carbidopa, started at age 1 year, was associated with sustained recovery from all neurologic signs. The patients were homozygous for a new recessive mutation in the GHI gene.