Is breastfeeding proving to be more of a challenge than you anticipated? The problem may lie in your DNA and a gene mutation that “affects the development of the mammary glands”

Is breastfeeding proving to be more of a challenge than you anticipated? The problem may lie in your DNA and a gene mutation that “affects the development of the mammary glands”

January 6, 2016
  • Many new mothers who try to breastfeed will simply be unable to, enduring breastfeeding challenges such as pain, cracked nipples, blocked ducts and lack of milk.
  • They may feel like they have failed and blame themselves.
  • According to a new study low levels of zinc may be the problem.

Low Levels of Zinc from Gene Mutation

The vast majority of new mothers intend to breastfeed, knowing it provides proven enrichment for their baby’s growth and development. A new study by a team from Penn State University has highlighted a mutated gene as the possible cause for some mother facing a breastfeeding setback. The study cited mothers carrying a mutation affecting the ZnT2 protein as having lower levels of zinc – a necessary nutrient for the proper development and functioning of the mammary glands.

The results of preceding research had shown ZnT2 protein as “crucial for secreting zinc into breast milk”.Women who carry a mutation in the gene that encodes ZnT2 were found to have breast milk that had “substantially lower” levels of zinc. This is cause for concern, since infants who are exclusively breastfed by mothers affected by the gene mutation suffer from severe zinc deficiency.

Scientists in the present study realized that loss or gain of function due to genetic variation may be widespread in women and at times is related to poor breast function indicators. They examined 54 breast-feeding women and found 36 per cent of them had one or more mutations in the ZnT2 protein. An atypical level of zinc in the breast milk of these women was linked to this genetic mutation.

The researchers identified 12 other previously unknown variants of ZnT2 in the study’s participants, linking abnormal levels of zinc to five of them. Associate professor of Cellular and Molecular Physiology and Pharmacology at Penn State, Dr. Shannon Keller, noted “We had no idea that genetic variation in ZnT2 would be so common.”

An additional finding of the study was that a problem with the ZnT2 protein was not automatically indicated by abnormal zinc levels. The scientists noted: “Importantly, among the subjects with “normal” milk (zinc levels), no variants in ZnT2 were detected.” However, 79 percent of women in the group with the lowest zinc levels had ZnT2 variants, while ZnT2 variants were detected in 29 per cent of the group with the highest zinc level.

The study therefore concluded that genetic variation of ZnT2 is a modifier of breast function.


The researchers are hopeful that what they have found out will aid doctors in readily identifying mothers who face breastfeeding woes. They note that this study’s findings are “an important step in identifying breastfed infants who are at risk for zinc deficiency”. They caution that in order to better understand how and why genetic variation affects breast function and the levels of zinc in breast milk, additional research is necessary.

Details of the study were published in the Journal of Mammary Gland Biology and Neoplasia.

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