Genetic renal disease classification by hormonal axes

Expanding the clinical spectrum of autosomal-recessive renal tubular dysgenesis: Two siblings with neonatal survival and review of the literature

Background

Autosomal‐recessive renal tubular dysgenesis (AR‐RTD) is a rare genetic disorder caused by defects in the renin‐angiotensin system that manifests as fetal anuria leading to oligohydramnios and Potter sequence. Although the most common outcome is neonatal death from renal failure, pulmonary hypoplasia, and/or refractory arterial hypotension; several cases have been reported that describe survival past the neonatal period.

Methods

Herein, we report the first family with biallelic ACE variants and more than one affected child surviving past the neonatal period, as well as provide a review of the previously reported 18 cases with better outcomes.

Results

While both siblings with identical compound heterozygous ACE variants have received different treatments, neither required renal replacement therapy. We show that both vasopressin and fludrocortisone in the neonatal period may provide survival advantages, though outcomes may also be dependent on the type of gene variant, as well as other factors.

Conclusion

While AR‐RTD is most often a lethal disease in the neonatal period, it is not universally so. A better understanding of the factors affecting survival will help to guide prognostication and medical decision‐making.

Growth Hormone and IGF1 Actions in Kidney Development and Function

Growth hormone (GH) exerts multiple effects on different organs including the kidneys, either directly or via its main mediator, insulin-like-growth factor-1 (IGF-1). The GH/IGF1 system plays a key role in normal kidney development, glomerular hemodynamic regulation, as well as tubular water, sodium, phosphate, and calcium handling. Transgenic animal models demonstrated that GH excess (and not IGF1) may lead to hyperfiltration, albuminuria, and glomerulosclerosis. GH and IGF-1 play a significant role in the early development of diabetic nephropathy, as well as in compensatory kidney hypertrophy after unilateral nephrectomy. Chronic kidney disease (CKD) and its complications in children are associated with alterations in the GH/IGF1 axis, including growth retardation, related to a GH-resistant state, attributed to impaired kidney postreceptor GH-signaling and chronic inflammation. This may explain the safety of prolonged rhGH-treatment of short stature in CKD.