Can phenylketonuria eat corn?

Written by Zeng Hai Jiang

Pediatrics

Updated on October 26, 2024

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People with phenylketonuria can eat corn. Phenylketonuria is a hereditary metabolic disease that can be treated through dietary control. Once diagnosed with phenylketonuria, one must stop a natural diet and switch to a low-phenylalanine diet. When the concentration of phenylalanine in the blood drops to an ideal level, natural foods can be gradually reintroduced in small amounts, but the diet must still adhere to low-protein and low-phenylalanine standards. Corn mainly consists of starch and does not contain phenylalanine, so individuals with phenylketonuria can eat corn.

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Written by Yan Xin Liang

Pediatrics

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Phenylketonuria Test Methods

The examination methods for phenylketonuria primarily include newborn screenings usually performed three to seven days after birth by drawing a blood sample from the heel and placing drops on specialized blood collection filter paper. Once dried, the sample is sent to a screening laboratory to determine the concentration of phenylalanine. If the phenylalanine concentration exceeds the cutoff value, further examinations and confirmatory tests are necessary, with the confirmatory test involving the measurement of phenylalanine concentration. Another method involves the analysis of urinary pterin profile, mainly used to differentiate dihydrobiopterin reductase deficiency. Additionally, gene analysis can be applied to detect mutations in genes such as phenylalanine hydroxylase, aiding in genetic diagnoses and prenatal diagnoses.

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Written by Yan Xin Liang

Pediatrics

1min 2sec

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Do children with mild phenylketonuria need treatment?

Phenylketonuria is a common amino acid metabolic disease, primarily due to the deficiency of phenylalanine hydroxylase, preventing phenylalanine from being converted into tyrosine. This leads to the accumulation of phenylalanine and its keto acids in the body, which are then excreted in large amounts in the urine. It is a relatively common genetic amino acid metabolic disorder and is inherited as an autosomal recessive trait. Even in cases of mild symptoms, treatment is still required. The main treatment is a low-phenylalanine diet, which involves dietary control, as phenylalanine is an essential amino acid for protein synthesis. Special phenylalanine-formula milk powder is fed to infants, and at this stage, it is appropriate to add some complementary foods such as starchy vegetables and fruits, focusing on low-protein foods. The goal of dietary treatment is to maintain an appropriate concentration of phenylalanine in the blood.

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Written by Hu Qi Feng

Pediatrics

34sec

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How is phenylketonuria diagnosed?

Phenylketonuria screening is routinely conducted in China for all newborns. This involves pricking the heel to collect peripheral blood, which is then dropped on specialized filter paper and dried. The samples are sent to a screening laboratory for the measurement of phenylalanine concentration. If the concentration exceeds the threshold, further testing for phenylalanine is conducted. Normally, the concentration should be less than 120 micromoles per liter. Additionally, an analysis of the urinary purine profile can be performed.

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Written by Yan Xin Liang

Pediatrics

1min 3sec

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Phenylketonuria has what symptoms?

Phenylketonuria is an autosomal recessive genetic disorder. It is the most common congenital amino acid metabolism disorder. Its main clinical characteristics include intellectual disability, light skin and hair pigmentation, and a mousy urine odor. This name arises from the excretion of large amounts of phenylketonic acid metabolites in children's urine, which leads to the characteristic odor. Typically, affected children appear normal at birth, but symptoms usually begin to appear between three to six months of age, with most significant symptoms evident by one year. The most prominent issue is delayed intellectual development, with intelligence quotients often falling below normal. Skin pigmentation usually becomes lighter several months after birth due to insufficient melanin synthesis, resulting in hair turning from black to yellow and a paler skin complexion. Additionally, a distinct mousy body odor is produced due to the excretion of excessive phenylacetic acid in urine and sweat.

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Written by Yan Xin Liang

Pediatrics

1min 18sec

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Phenylketonuria is caused by how?

Phenylketonuria is caused by how? It is an autosomal recessive genetic disease, mainly due to a mutation in the phenylalanine hydroxylase gene, which leads to a reduction in the activity of phenylalanine hydroxylase. Phenylalanine is an essential amino acid in the human body. The phenylalanine ingested is partly used for protein synthesis, and the rest is converted into tyrosine by the action of phenylalanine hydroxylase, with only a small amount of phenylalanine being converted into phenylpyruvic acid through a minor metabolic pathway under the action of transaminase. Due to the reduced activity of phenylalanine hydroxylase, phenylalanine cannot be converted into tyrosine, resulting in an extremely high concentration of phenylalanine in the blood, cerebrospinal fluid, and tissues. Through a bypass metabolism, a large amount of phenylpyruvic acid, phenylacetic acid, phenyllactic acid, and p-hydroxyphenylacetic acid are produced. High concentrations of phenylalanine and its metabolites thus lead to brain damage. Due to the synthesis disorder of tyrosine, this also leads to symptoms such as light skin and hair pigmentation.