From Skin to Kidneys: Cutaneous Clues of Renal Disease in Children

Pallister-Hall syndrome, GLI3, and kidney malformation

Pallister-Hall syndrome (PHS) is a rare autosomal dominant disease diagnosed by the presence of hypothalamic hamartoma, mesoaxial polydactyly and a truncating variant in the middle third of the GLI-Kruppel family member 3 (GLI3) gene. PHS may also include a wide range of clinical phenotypes affecting multiple organ systems including congenital anomalies of the kidney and urinary tract (CAKUT). The observed clinical phenotypes are consistent with the essential role of GLI3, a transcriptional effector in the hedgehog (Hh) signaling pathway, in organogenesis. However, the mechanisms by which truncation of GLI3 in PHS results in such a variety of clinical phenotypes with variable severity, even within the same organ, remain unclear. In this study we focus on presentation of CAKUT in PHS. A systematic analysis of reported PHS patients (n = 78) revealed a prevalence of 26.9% (21/78) of CAKUT. Hypoplasia (± dysplasia) and agenesis were the two main types of CAKUT; bilateral and unilateral CAKUT were reported with equal frequency. Examination of clinical phenotypes with CAKUT revealed a significant association between CAKUT and craniofacial defects, bifid epiglottis and a Disorder of Sex Development, specifically affecting external genitalia. Lastly, we determined that PHS patients with CAKUT predominately had substitution type variants (as opposed to deletion type variants in non-CAKUT PHS patients) in the middle third of the GLI3 gene. These results provide a foundation for future work aimed at uncovering the molecular mechanisms by which variant GLI3 result in the wide range and severity of clinical features observed in PHS.

Renal manifestations in children with neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is an autosomal-dominant neurocutaneous syndrome affecting various parts of the body, including the renovascular and urinary systems. We evaluated the renovascular, urinary, glomerular, and tubular functions of children with NF1. We compared blood pressures, urinary findings, and renal glomerular and tubular functions in children with NF1 with those of a healthy age- and gender-matched control group. We evaluated 46 NF1 patients and 33 healthy controls. The mean ages of the NF1 group (female/male: 20/26) and the control group (female/male: 15/18) were 10.1 ± 4.6 and 10.6 ± 4.3 years respectively. Six NF1 patients were hypertensive. The mean blood pressures of the NF1 group were significantly higher than those of the control group. Renal artery stenosis was detected in one NF1 patient. Urinary tract anomalies were evident in 21.7% of NF1 but only 9% of control subjects. The mean estimated glomerular filtration rate (eGFR) of the NF1 group was significantly lower than that of the control group. Six NF1 patients evidenced eGFRs < 90 mL/min. In the NF1 group, tubular phosphorus reabsorption was significantly lower and uric acid excretion significantly higher than in the control group.Conclusion: Hypertension, urinary tract anomalies, and impaired renal function were more common in NF1 patients than healthy controls. Regular blood pressure measurements and evaluation of urinary tract and kidney function are essential for NF1 patients. What is Known: • NF1 is most commonly associated with systemic hypertension due to renal artery vasculopathy and the development of a pheochromocytoma. • Hydronephrosis and bladder involvement have been documented in NF1. What is New: • Renal glomerular and tubular functions may be affected in NF1.