From newborn screening to preconception care: PKU mothers and their offspring

1. From newborn screening to preconception care: PKU mothers and their offspring Violanda Grigorescu, MD, MSPH, William Young, PhD, Karen Andruszewski, MA, Steve Korzeniewski, MS, MA Michigan Department of Community Health, Division of Genomics, Perinatal Health and Chronic Disease Epidemiology Lesson learned: The Starfish Story Once upon a time, there was a wise man who used to go to the ocean to do his writing. He had a habit of walking on the beach before he began his work. One day, as he was walking along the shore, he looked down the beach and saw a human figure moving like a dancer. He smiled to himself at the thought of someone who would dance to the day, and so, he walked faster to catch up. As he got closer, he noticed that the figure was that of a young man, and that what he was doing was not dancing at all. The young man was reaching down to the shore, picking up small objects, and throwing them into the ocean. He came closer still and called out "Good morning! May I ask what it is that you are doing?" The young man paused, looked up, and replied "Throwing starfish into the ocean." "I must ask, then, why are you throwing starfish into the ocean?" asked the somewhat startled wise man. To this, the young man replied, "The sun is up and the tide is going out. If I don't throw them in, they'll die.“ Upon hearing this, the wise man commented, "But, young man, do you not realize that there are miles and miles of beach and there are starfish all along every mile? You can't possibly make a difference!“ At this, the young man bent down, picked up yet another starfish, and threw it into the ocean. As it met the water, he said, "It made a difference for that one." Adapted from The Star Thrower by Loren Eiseley (1907 – 1977) Michigan’s Newborn Screening Update, Winter 2007 • Table 1: Disorders Included in the Newborn Screening Panel • Michigan, 2006 Results There were 350 PKU cases diagnosed in Michigan between 1965 and 1992, 169 (48%) were women. Information was found on 54 women that had 91 pregnancies. Table 2: Distribution by type of PKU Pregnancy outcomes: Less than one third (28; 30.8%) of the pregnancies ended in abortions (12 therapeutic and 16 spontaneous) and 63 (69.2%) in live births. Table 3: Live births outcomes by type of PKU In total, nearly one-fourth of the newborns suffered microcephaly; among mothers with classic PKU the proportion of newborns with microcephaly was much greater (57.1%). However, the proportion of newborns identified with microcephaly is likely under-reported in our study given that no information on pregnancy outcome could be found for 30% of the PKU mothers. Background Newborn screening (NBS) is a process of early identification of health conditions followed by their subsequent timely treatment before the onset of disease processes thereby minimizing the risk of long-term sequelae. Depending on the condition, potential outcomes of disorders included in the NBS panel include but are not limited to brain/neurological damage, mental retardation, damage to the liver, eyes, spleen, stroke, or death if not detected early. To prevent such outcomes from occurring, NBS programs test blood spots collected from infants during the first few days of life for signs of treatable disorders. Michigan Newborn Screening Milestones - 1960s: Dr. Robert Gutherie developed the bacterial inhibition assay to diagnose phenlyketonuria (PKU) by determining the level of the amino acid phenylalanine in a drop of a baby’s blood placed on a strip of filter paper. - 1965: Dr. Stanley Read at the Michigan Department of Public Health and Dr. Richard Allen at the University of Michigan introduced NBS for PKU to Michigan - 1977: a test for congenital hypothyroidism (CH) was added to the NBS panel - 1985: screening for galactosemia was initiated. - 1987: The Public Act 14 of 1987 mandated further expansion of screening with the addition of three disorders, biotinidase deficiency, maple syrup urine disease (MSUD), and hemoglobinopathies such as sickle cell disease. The act also designated the state laboratory as the sole testing site, mandated a fee to fund the program, and added comprehensive programs for follow-up, medical management, and quality assurance. - 1993: Congenital adrenal hyperplasia (CAH) was added to the screening panel - 2003: Tandem mass spectrometry (TMS) was introduced and thus enabled the state laboratory to efficiently screen for a large number of disorders detectable from a single blood spot. The first was medium chain acylCoAdehydrogenase deficiency (MCAD), a disorder of fatty acid oxidation that can result in sudden death during periods of fasting. - 2004: Further expansion of the NBS screening panel to include three other amino acid disorders: homocystinuria (HCY), citrullinemia (CIT) and argininosuccinicaciduria (ASA). - 2005: a pilot project was initiated to expand the screening panel to 48 disorders by adding the additional TMS disorders recommended by the American College of Medical Genetics (ACMG) and the March of Dimes. - October 1, 2007: Screening for Cystic Fibrosis began, thus meeting another recommendation of the ACMG. ( Detailed information about the disorders in the screening panel, confirmation of diagnoses, and follow-up of positive tests including algorithms can be found in the NBS Procedure Manual available at: www.michigan.gov/newbornscreening ) Phenylketonuria (PKU) is known as a genetic disorder that results in severe mental retardation if not identified and treated quickly with a diet low in phenylalanine (Phe); Maternal PKU (MPKU) syndrome occurs when females with PKU do not adhere to strict dietary treatment; The teratogenic effects of elevated maternal blood phenylalanine on the developing fetus could result in cognitive and physical problems (i.e., congenital heart defects, microcephaly, dysmorphic facial features, mental retardation; Emerging needs for prevention efforts targeted to women with PKU: 1/adherence to dietary treatment; 2/ continued education about the risks for offspring; 3/continued and careful health status assessment prior to conception, during pregnancy and after delivery. Abstract Background: Phenylketonuria (PKU) is known as a genetic disorder that results in severe mental retardation if not identified and treated quickly with a diet low in phenylalanine (Phe). Michigan as well as most other states, initiated PKU screening in the 1960's. About twenty years later, some of the children born to females with PKU, in the U.S. and other countries, presented with a myriad of cognitive and physical problems (i.e., congenital heart defects, microcephaly, dysmorphic facial features, mental retardation) due to the teratogenic effects of elevated maternal blood phenylalanine on the developing fetus. This is known as the Maternal PKU (MPKU) syndrome that occurs when females with PKU do not adhere to strict dietary treatment. Assessing the health status of women with PKU is needed prior to conception. Objective: To understand the long term implications of NBS program and the impact on strategies and standard of care as they relate to preconceptional health. Methods: The clinical database of PKU patients born between 1965 and 1992 and treated at the Metabolic Medical Management Center was used for this study. The incomplete information on Phe levels limited our ability to compare pregnancy outcomes in diet-controlled PKU versus non-controlled by using the retrospective cohort design. Univariate and bivariate analyses were conducted instead, as permitted by the available data. Results: There were 350 PKU cases diagnosed in Michigan between 1965 and 1992, 169 (48%) were women . Information was found on 54 women that had 91 pregnancies. Of 91 pregnancies, 37% (34) were to 25 women (46.3% of 54) having classic PKU, 29.7% (27) to women with a mild form (13 women; 24.1% of 54) and 33% (30) to those having Hyperphe (16 women; 29.6% of 54). Less than one third (28; 30.8%) ended in abortions (12 therapeutic and 16 spontaneous) and 63 (69.2%) in live births. Twenty-eight offspring were reported as normal at birth (44.4%) and nearly one in four (22.2%) as having microcephaly. No information was found on more than half. Public Health Implications: As those diagnosed through this program become adults, public health professionals are challenged to include preconception assessment within NBS long-term follow up strategies and standards of care. Conclusion The expansion of Newborn Screening panel was not mirrored by the development of corresponding long term follow up strategies and standards of care. This was due in part to the limited number of professionals with corresponding training and understanding of the specifics of each hereditary condition identified through Newborn Screening. Public Health Implications As those diagnosed through this program become adults, public health professionals are challenged to: 1/include preconception and interconception health assessment within Newborn Screening long-term follow up strategies and standards of care 2/educate other providers about the health challenges/needs of those diagnosed through Newborn Screening. Data source A clinical database including information on PKU patients born between 1965 and 1992 and treated at the Metabolic Medical Management Center was used for this study. Study design The incomplete information on Phe levels limited our ability to compare pregnancy outcomes in a diet-controlled PKU versus non-controlled fashion by using the retrospective cohort design. Accordingly, we conducted a descriptive study utilizing univariate and bivariate analyses as permitted by the available data. ”Success isn’t measured by the position you reach in life; It’s measured by the obstacles you overcome.” Booker T. Washington Michigan’s Newborn Screening Update, Winter 2007