Screening the newborn for disease

Those associated with the screening of newborns for genetic diseases and for determining genetic diseases in newborns after some abnormalities are noted. 

In addition to blood, certain types of specimens are submitted to the Pediatric laboratory which would not be commonly seen elsewhere. An example of this is sweat for analysis of chloride. The process of obtaining the sweat by iontophoresis usually falls to the personnel of the Laboratory of Neonatology (17). Stool for analysis of lipids and trypsin is more commonly submitted to the Laboratory of Neonatology than to the laboratory which services the adult population. The reason for this is that one is screening for certain intestinal diseases characteristic of infants and newborns which are rare in adults. Such conditions would be celiac disease, cystic fibrosis and others. 

Lipid Screening. The problems of lipid analysis in the newborn is difficult because of the fact that most methods for analysis for lipids require substantial amounts of serum, yet a total lipid determination is very important in various types of disease. This problem can be solved by thin-layer chromatography (59). Figure 38 shows a typical pattern obtained when an extract 7rom 10 microliters of serum is subjected to thin-layer chromatography. If these specimens are scanned, and an internal standard is run, one can obtain a rough approximation of the distribution of the various lipids in the serum. This is shown in Figure 39, in which a normal specimen is run in an adult. 

Last, but not least, there is always the need for interpretation of results and assessment of outcomes, particularly now that tandem mass spectrometry is increasingly embedded in newborn screening. This laboratory guide serves the expertise upon which interpretation depends. Accordingly, the correct use of a laboratory guide is certain to be multidisciplinary, and at the end of the inquiry and analysis, one will know better why this person has this disease, now. 

Screening newborns for genetic diseases can be highly cost-effective, especially in the case of PKU. The tests (no longer relying on urine odor) are relatively inexpensive, and the detection and early treatment of PKU in infants (eight to ten cases per 100,000 newborns) saves millions of dollars in later health care costs each year. More importantly, the emotional trauma avoided by early detection with these simple tests is inestimable. 

An inability to degrade amino acids causes many genetic diseases in humans. These diseases include phenylketonuria (PKU), which results from an inability to convert phenylalanine to tyrosine. The phenylalanine is instead transaminated to phenylpyruvic acid, which is excreted in the urine, although not fast enough to prevent harm. PKU was formerly a major cause of severe mental retardation. Now, however, public health laboratories screen the urine of every newborn child in the United States for the presence of phenylpyru-vate, and place children with the genetic disease on a synthetic low-phenylalanine diet to prevent neurological damage. 

While most individuals with sickle cell disease have Mediterranean or African ancestry, it is common practice to screen all newborns in the United States for the condition. Research shows that early intervention can reduce the risk of serious infection, the leading cause of death in children with sickle cell disease. Intensive chemotherapy and stem cell... 

W23. Woolf, L. I., Large-scale screening for metabolic disease in the newborn in Great Britain. In Phenylketonuria and Allied Metabolic Diseases (J. A. Anderson and K. F. Swaiman, eds.), pp. 50-61. US Dep. of Health, Educ., and Welfare, Childrens Bureau, US Govt. Printing Ofiice, Washington, D.C., 1967. 

The y- and 5-chain mutants are difficult to study because of the small fraction of HbF and HbA2 present in adult erythrocytes. Overt clinical symptoms associated with y- and 5-chain variants are rare. By routine screening, 14 5-globin variants have been discovered but are of no clinical consequence. Thirty-five mutant y sequences (involving the Gy or the Ay chains) have been identified. They are all benign except for HbF Poole [Gyl30(H8) Tyr —> Gly], an unstable hemoglobin that causes hemolytic disease in the newborn. 

Biotinidase deficiency is an autosomal recessive disorder with an estimated incidence of 1 in 72,000-126,0(X). Many newborn-screening programs of genetic diseases include testing for this enzyme. Prompt treatment with oral biotin administration of 5-20 mg/d in affected infants will prevent clinical consequences. If the treatment is delayed, neurological manifestations (e.g., hearing loss and optic atrophy) and developmental delay occur and may not revert to normal. 

If the genetic bases of phenotypes are known, disease risks may be assessed before disease onset. This is desirable only if preventive or therapeutic action can be taken. Otherwise, the psychological burden for the individual may be unwarranted. Ideally, preventive steps are undertaken in due time. Pre-symptomatic screening is applied, if disease prevails in famihes (for example, breast cancer and variation in estrogen receptor subunits or Hunting-ton s disease). The same is trae for prenatal and newborn screening, if family histories indicate the need (for example phenylketonuria, galactosemia, hypothyroidism). 

Donor placenta is obtained after elective cesarean, and with informed maternal consent. Maternal donors are screened at deUvery usually by physical exam, reviewing medical history and standard questionnaire to assess the possibility of transmittable diseases. Suitability for transplant is determined by the absence of any infectious, malignant, neurological and autoimmune diseases and other exposures or social habits deemed improper to transplantation. Donors are screened for transmittable diseases such as HIV, HCV, hepatitis B, hepatitis C, and syphilis. These screening takes place predonation and bmonths after donation. No harm to either the newborn or maternal donor is encountered during the procurement process. - ... 

---