COL4A3 and Nephropathy: 20.3-Suggestion: Living kidney donation is not advisable in individuals heterozygous for a single P/LP variant in COL4A3, COL4A4, or COL4A5 aged under 40 years, or at any age if there is clinical or histological evidence of kidney damage (e.g. albuminuria, reduced eGFR or interstitial fibrosis/tubular atrophy greater than what would be normal for their age). (Grade D, expert opinion)