Background Despite the popularity of hyaluronic acid (HA) filler treatments, few publications focus on their effects on adipose tissue. Objectives The authors assessed the deposition pattern in the subcutis of injected HA, the tissue response at short and intermediate term, and the effects of remodeling the filler by strong finger pressure immediately after the treatment. Methods Two brands, specifically developed by the industry for deep injection, were compared. The gels were injected subcutaneously in 5 candidates for abdominoplasty or breast reduction, in the area of excision, 6 to 98 days before surgery. Ultrasound measurements and films were compared with postoperative histological findings. Tissue response was scored semi-quantitatively. Results Real-time ultrasound showed a slightly different deposition pattern of the 2 brands. Histologically, both were present in large pools of the same magnitude and looked the same. Linear retrograde injection sometimes resulted in a globular deposit due to elastic recoil of septae. After remodeling and over time, HA deposits became difficult to detect by ultrasound. Firm remodeling of the tissue immediately after injection or time had no significant effect on filler spread or tissue response. Except for 1 zone of granuloma formation, tolerance for both fillers was good. Conclusions HA deposition in adipose tissue occurs in much larger pools than in the dermis. Ultrasound examination is useful during and immediately after the injection but less reliable after filler remodeling or over time. Filler deposition can be less precise, and reshaping by finger pressure can have less effect than expected. Level of Evidence: 4

Background Trichothiodystrophy (TTD) describes a group of rare genetic disorders of DNA repair, characterized by sulphur‐deficient hair, skin anomalies and systemic complications like preterm delivery, neurological impairment, haematological and ophthalmological abnormalities and life‐threatening infections. Objectives The aim of this case report was to investigate the contribution of the gene mutation to the phenotype. Methods We describe the clinical and molecular characteristics of a family with two TTD‐affected siblings who died before the age of 2 years. Results The causal mutated gene is the ERCC2 gene, and one of the identified mutations is the c.2164C>T (p.Arg722Trp) variant. The association of this mutation with a severe TTD phenotype was suggested earlier in literature, and the present family adds further evidence to this hypothesis. Conclusion Accurate identification of the underlying genetic defect can guide the clinical follow‐up and counselling of patients and their families.

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