Impact of Next-Generation Sequencing on the Diagnosis and Treatment of Congenital Anemias

Congenital anemias are a wide spectrum of diseases including hypoproliferative anemia syndromes, dyserythropoietic anemias, sideroblastic anemias, red blood cell membrane and enzymatic defects, hemoglobinopathies, and thalassemia syndromes. The various congenital anemia syndromes may have similar clinical and laboratory presentations, making the diagnosis challenging. The traditional work-up, which includes a complete blood count, blood smears, bone marrow studies, flow cytometry, and the osmotic fragility test, does not always lead to the diagnosis. Specialized tests such as red blood cell enzyme activity and ektacytometry are not widely available. In addition, red blood cell transfusions may mask some of the laboratory characteristics. Therefore, genetic testing is crucial for accurate diagnosis of patients with congenital anemias. However, gene-by-gene testing is labor intensive because of the large number of genes involved. Thus, targeted next-generation sequencing using custom-made gene panels has been increasingly utilized, with a high success rate of diagnosis. Accurate genetic diagnosis is important for determining specific therapeutic modalities, as well as for avoiding splenectomy when contraindicated. In addition, molecular diagnosis can allow for genetic counseling and prenatal diagnosis in severe cases. We suggest a work-up scheme for patients with congenital anemias, including early incorporation of targeted next-generation sequencing panels.

Role of fetal intertwin difference in middle cerebral artery peak systolic velocity in predicting neonatal twin anemia-polycythemia sequence

OBJECTIVES

To evaluate the relationship between the fetal intertwin difference in middle cerebral artery peak systolic velocity (MCA-PSV) and intertwin difference in hemoglobin (Hb) concentration at birth in monochorionic diamniotic (MCDA) twin pregnancies in order to assess its potential role in the prediction of twin anemia-polycythemia sequence (TAPS).

METHODS

This was a retrospective cohort study of MCDA twin pregnancies delivered between January 2012 and January 2018. All pregnancies with measurements of MCA-PSV within 7 days prior to delivery and in which neonatal Hb concentration was available were included. The correlation between fetal intertwin difference in MCA-PSV, expressed in multiples of the median (MoM), and neonatal intertwin difference in Hb concentration was investigated. Receiver-operating characteristics (ROC) curve analysis was used to assess the performance of fetal intertwin difference in MCA-PSV for predicting intertwin difference in Hb > 90^th centile at birth.

RESULTS

A total of 154 out of 256 MC twin pregnancies fulfilled the inclusion criteria. Fetal intertwin difference in MCA-PSV MoM correlated positively with neonatal intertwin difference in Hb concentration (r = 0.79; P < 0.001). The 90^th centile for intertwin difference in Hb was 7.25 g/dL. There were 15 (9.7%) cases with a Hb difference ≥ 7.25 g/dL at birth. ROC curve analysis showed a high accuracy of fetal intertwin MCA-PSV MoM difference for the prediction of neonatal intertwin Hb difference ≥ 7.25 g/dL at birth (area under the ROC curve, 0.976 (95% CI, 0.935-0.993); P = 0.012). The optimal cut-off for intertwin MCA-PSV MoM difference was 0.373, with a sensitivity of 93.3% (95% CI, 68.1-99.8%) and a specificity of 95.7% (95% CI, 90.8-98.4%). The positive predictive value was 70% (95% CI, 45.7-88.1%) and the negative predictive value was 99.3% (95% CI, 95.9-100%).

CONCLUSION

Our findings show that fetal intertwin MCA-PSV MoM difference is a good predictor of neonatal intertwin Hb concentration difference > 90^th centile and potentially of TAPS. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Improved prediction of twin anemia-polycythemia sequence by delta middle cerebral artery peak systolic velocity: new antenatal classification system

OBJECTIVES

To investigate the diagnostic accuracy of delta middle cerebral artery peak systolic velocity (MCA-PSV) > 0.5 multiples of the median (MoM) and compare its predictive value with that of the current MCA-PSV cut-off values of > 1.5 MoM in the donor and < 1.0 MoM in the recipient, for the diagnosis of twin anemia-polycythemia sequence (TAPS) in monochorionic twin pregnancy.

METHODS

This was a retrospective consecutive cohort study comprising all uncomplicated monochorionic twin pregnancies and twin pregnancies with a postnatal diagnosis of TAPS managed between 2003 and 2017 in the Dutch national referral center for fetal therapy. Cases with incomplete MCA-PSV Doppler measurements 1 week prior to delivery or with incomplete hemoglobin measurements within 1 day after birth were excluded. The postnatal diagnosis of TAPS was based on an intertwin hemoglobin difference > 8 g/dL and at least one of the following: reticulocyte count ratio > 1.7 or presence of minuscule anastomoses on the placental surface. We compared the predictive accuracy of the current diagnostic method using MCA-PSV cut-off values of > 1.5 MoM in the donor and < 1.0 MoM in the recipient with that of a new method based on intertwin difference in MCA-PSV > 0.5 MoM for prediction of TAPS.

RESULTS

In total, 45 uncomplicated and 35 TAPS monochorionic twin pregnancies were analyzed. The sensitivity and specificity of the cut-off MCA-PSV values (donor > 1.5 MoM, recipient < 1.0 MoM) to predict TAPS was 46% (95% CI, 30-62%) and 100% (95% CI, 92-100%), respectively; positive predictive value was 100% (95% CI, 81-100%) and negative predictive value 70% (95% CI, 58-80%). Delta MCA-PSV showed a sensitivity of 83% (95% CI, 67-92%) and a specificity of 100% (95% CI, 92-100%); the positive and negative predictive values were 100% (95% CI, 88-100%) and 88% (95% CI, 77-94%), respectively. Of the 35 cases with TAPS diagnosed postnatally, 13 twin pairs showed a delta MCA-PSV > 0.5 MoM but did not fulfill the cut-off MCA-PSV criteria. Of these 13 TAPS twins, nine donors and four recipients had normal MCA-PSV values. There was a high correlation between delta MCA-PSV and intertwin difference in hemoglobin level (R = 0.725, P < 0.01).

CONCLUSION

Delta MCA-PSV > 0.5 MoM has a greater diagnostic accuracy for predicting TAPS compared to the current MCA-PSV cut-off criteria. We therefore propose a new antenatal classification system for TAPS. In monochorionic twin pregnancies with delta MCA-PSV > 0.5 MoM on Doppler ultrasound, but normal MCA-PSV values in the donor or recipient, obstetricians should be aware of the therapeutic implications and neonatal morbidities associated with TAPS. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Emerging cellular and gene therapies for congenital anemias

Congenital anemias comprise a group of blood disorders characterized by a reduction in the number of peripherally circulating erythrocytes. Various genetic etiologies have been identified that affect diverse aspects of erythroid physiology and broadly fall into two main categories: impaired production or increased destruction of mature erythrocytes. Current therapies are largely focused on symptomatic treatment and are often based on transfusion of donor-derived erythrocytes and management of complications. Hematopoietic stem cell transplantation represents the only curative option currently available for the majority of congenital anemias. Recent advances in gene therapy and genome editing hold promise for the development of additional curative strategies for these blood disorders. The relative ease of access to the hematopoietic stem cell compartment, as well as the possibility of genetic manipulation ex vivo and subsequent transplantation in an autologous manner, make blood disorders among the most amenable to cellular therapies. Here we review cell-based and gene therapy approaches, and discuss the limitations and prospects of emerging avenues, including genome editing tools and the use of pluripotent stem cells, for the treatment of congenital forms of anemia. © 2016 Wiley Periodicals, Inc.

Prevalence of anemia and associations between neonatal iron status, hepcidin, and maternal iron status among neonates born to pregnant adolescents

BACKGROUND

Little is known about anemia and iron status in US newborns because screening for anemia is typically not undertaken until 1 y of age. This study was undertaken to characterize and identify determinants of iron status in newborns born to pregnant adolescents.

METHODS

Pregnant adolescents (≤ 18 y, n = 193) were followed from ≥ 12 wk gestation until delivery. Hemoglobin, ferritin, soluble transferrin receptor, serum iron, hepcidin, erythropoietin (EPO), IL-6, and C-reactive protein were assessed in maternal and cord blood.

RESULTS

At birth, 21% of the neonates were anemic (Hb < 13.0 g/dl) and 25% had low iron stores (ferritin < 76 µg/l). Cord serum ferritin concentrations were not significantly associated with gestational age (GA) at birth across the range of 37-42 wk. Neonates born to mothers with ferritin < 12 µg/l had significantly lower ferritin (P = 0.003) compared to their counterparts. Hepcidin and IL-6 were significantly (P < 0.05) higher in neonates born to mothers with longer durations of active labor.

CONCLUSION

Given the importance of the iron stores at birth on maintenance of iron homeostasis over early infancy, additional screening of iron status at birth is warranted among those born to this high risk obstetric population.

An autosomal recessive syndrome of joint contractures, muscular atrophy, microcytic anemia, and panniculitis-associated lipodystrophy

CONTEXT

Genetic lipodystrophies are rare disorders characterized by partial or complete loss of adipose tissue and predisposition to insulin resistance and its complications such as diabetes mellitus, hypertriglyceridemia, hepatic steatosis, acanthosis nigricans, and polycystic ovarian syndrome.

OBJECTIVE

The objective of the study was to report a novel autosomal recessive lipodystrophy syndrome.

RESULTS

We report the detailed phenotype of two males and one female patient, 26-34 yr old, belonging to two pedigrees with an autosomal recessive syndrome presenting with childhood-onset lipodystrophy, muscle atrophy, severe joint contractures, erythematous skin lesions, and microcytic anemia. Other variable clinical features include hypergammaglobulinemia, hepatosplenomegaly, generalized seizures, and basal ganglia calcification. None of the patients had diabetes mellitus or acanthosis nigricans. Two had mild hypertriglyceridemia and all had low levels of high-density lipoprotein cholesterol. Skin biopsy of an erythematous nodular skin lesion from one of the patients revealed evidence of panniculitis. The lipodystrophy initially affected the upper body but later became generalized involving abdomen and lower extremities as well.

CONCLUSIONS

We conclude that these patients represent a novel autoinflammatory syndrome resulting in joint contractures, muscle atrophy, microcytic anemia, and panniculitis-induced lipodystrophy. The molecular genetic basis of this disorder remains to be elucidated.

Knockout of Slc25a19 causes mitochondrial thiamine pyrophosphate depletion, embryonic lethality, CNS malformations, and anemia

SLC25A19 mutations cause Amish lethal microcephaly (MCPHA), which markedly retards brain development and leads to alpha-ketoglutaric aciduria. Previous data suggested that SLC25A19, also called DNC, is a mitochondrial deoxyribonucleotide transporter. We generated a knockout mouse model of Slc25a19. These animals had 100% prenatal lethality by embryonic day 12. Affected embryos at embryonic day 10.5 have a neural-tube closure defect with ruffling of the neural fold ridges, a yolk sac erythropoietic failure, and elevated alpha-ketoglutarate in the amniotic fluid. We found that these animals have normal mitochondrial ribo- and deoxyribonucleoside triphosphate levels, suggesting that transport of these molecules is not the primary role of SLC25A19. We identified thiamine pyrophosphate (ThPP) transport as a candidate function of SLC25A19 through homology searching and confirmed it by using transport assays of the recombinant reconstituted protein. The mitochondria of Slc25a19(-/-) and MCPHA cells have undetectable and markedly reduced ThPP content, respectively. The reduction of ThPP levels causes dysfunction of the alpha-ketoglutarate dehydrogenase complex, which explains the high levels of this organic acid in MCPHA and suggests that mitochondrial ThPP transport is important for CNS development.

Parvovirus B19 infection in pregnancy

Parvovirus B19 is a small single-stranded DNA virus and a potent inhibitor of erythropoiesis, due to its cytotoxicity to erythroid progenitor cells. Infection with parvovirus B19 during pregnancy can cause several serious complications in the fetus, such as fetal anemia, neurological anomalies, hydrops fetalis, and fetal death. Early diagnosis and treatment of intrauterine parvovirus B19 infection is essential in preventing these fetal complications. Testing maternal serum for IgM antibodies against parvovirus B19 and DNA detection by PCR can confirm maternal infection. If maternal infection has occurred, ultrasound investigation of the fetus and measurement of the peak systolic flow velocity of the middle cerebral artery are sensitive non-invasive procedures to diagnose fetal anemia and hydrops. Intrauterine transfusion is currently the only effective treatment to alleviate fetal anemia, but if the fetus is (near) term, induction of delivery should be considered. Most maternal infections with parvovirus B19 occur through contact with infected children at home. Individual counseling of susceptible pregnant women will reduce unnecessary fetal deaths.

Risk of infant anemia is associated with exclusive breast-feeding and maternal anemia in a Mexican cohort

The WHO recommends exclusive breast-feeding (EBF) for the first 6 mo of life to decrease the burden of infectious disease. However, some are concerned about the effect of EBF >6 mo on iron status of children in developing countries in which anemia is prevalent. This study examines the risk of anemia in relation to the duration of EBF and maternal anemia in a birth cohort studied between March 1998 and April 2003. All infant birth weights were >or=2.2 kg. All mothers received home-based peer counseling to promote EBF. Infant feeding data were collected weekly. Nurses measured hemoglobin (Hb) values every 3 mo. Hb was measured in 183 infants at 9 mo of age. Anemia at 9 mo was defined as a Hb value <100 g/L. EBF was defined by WHO criteria and ranged in duration from 0 to 31 wk. At 9 mo, Hb (mean +/- SEM) was 114 +/- 0.9 g/L; 23 children (12.5%) had Hb levels <100 g/L. EBF >6 mo, but not EBF 4-6 mo, was associated with increased risk of infant anemia compared with EBF <4 mo (odds ratio=18.4, 95% CI=1.9, 174.0). Maternal anemia was independently (P=0.03) associated with a 3-fold increased risk of infant anemia. These associations were not explained by confounding with other maternal or infant factors. By linear regression, a lower infant Hb at 9 mo was associated with increased EBF duration among mothers who had a history of anemia (beta=-0.07, P=0.003), but not among mothers with no history of anemia. Infants who are exclusively breast-fed for >6 mo in developing countries may be at increased risk of anemia, especially among mothers with a poor iron status; greater attention to this issue is warranted.

[Blood product transfusion in the neonatal period]

Newborn infants in intensive care units, especially those born premature, are at particular risk for blood transfusion adverse effects. Aside improvements in the preparation of specific blood products for the neonatal period, such as multiple packed cells preparations from a single donor for multiple transfusions in premature infants, progress has involved prophylaxis of anemia of prematurity as well. Recombinant human erythropoietin has proven to be beneficial with high range evidence. Also, alternative methods have been proposed to compensate for the delay in the effect of rHuEPO, such as delayed clamping of umbilical cord at birth, or autologous placental blood transfusion. However, a better understanding of the indications of blood transfusion and the provision of practice guidelines may justify a re-evaluation of prophylactic strategies for anemia of prematurity.

Immunoglobulin and peripheral B-lymphocyte concentrations in Fell pony foal syndrome

REASONS FOR PERFORMING STUDY

Fell pony foals are affected by a congenital fatal disease that leads to profound anaemia and immunodeficiency. Previous studies comparing healthy and affected foals have shown normal T-cell populations, but a severe B-lymphopenia.

OBJECTIVES

To measure the levels of individual immunoglobulin subisotypes in normal and affected Fell ponies and correlate these levels with the number of peripheral B-lymphocytes.

METHODS

Serum levels of individual immunoglobulin subisotypes were measured by ELISA and correlated with the number of peripheral B-lymphocytes (measured by flow cytometry).

RESULTS

Affected foals had significantly reduced serum levels of IgM, IgGa, IgGb and IgG(T) that coincided with the normal reduction in maternally derived immunoglobulin in foals and, with the exception of IgGb, correlated strongly with the B-lymphopenia.

CONCLUSIONS

These data suggest that affected foals are unable to produce their own immunoglobulins. Therefore, once maternal immunity has waned, it may be the lack of specific foal-derived immunoglobulin that gives rise to the clinical signs of immunodeficiency.

POTENTIAL RELEVANCE

Measurement of IgM after age 4 weeks may provide a more accessible means of confirming the status of future affected Fell pony foals than the measurement of B-lymphocytes (a technique limited to a few specialist laboratories).

[Prenatal parvovirus B19 infection in fetus]

OBJECTIVE

To analyse 3 cases of parvovirus B19 infection in a pregnant woman followed by transplacental transmission to the fetus.

DESIGN

A reprospective study.

SETTING

Department of Obstetrics and Gynecology, University Hospital, Olomouc.

METHOD

Parvovirus B19 vertical transmission from a pregnant woman to the fetus was diagnosed in 3 cases. Serologic testing of IgG and IgM antibodies against parvovirus B19, cytological bone marrow examination and parvovirus B19 DNA analysis by PCR methods were performed. The fetal anemia was predicted by measurements of peak systolic velocities in the middle cerebral artery (MCA-PSV).

RESULTS

There were three pregnancies in all (1st - single, 2nd and 3rd - dizygotic twins). In the 1st and 2nd pregnancy the diagnosis of parvovirus B19 infection was set on the basis of erythroblastopenia diagnosed in the neonatal period or early infancy. In the 2nd pregnancy (dizygotic twins) intrauterine death of one twin occured. In the 3rd case (dizygotic twins) the diagnosis was already set in the 20th week of pregnancy. Subsequently the fetal anemia was predicted by doppler examination. The fetuses did not require invasive intrauterine intervention and mild anemia was diagnosed after delivery. Progressive intrauterine growth retardation of one twin was observed. Neither cardiomegaly nor fetal hydrops did not occur. All mothers were asymptomatic during the whole pregnancy.

CONCLUSION

Parvovirus B19 infection should be excluded in all cases of nonimmune fetal hydrops, severe fetal anemia, cardiomegaly, intrauterine growth retardation (IUGR) and chronic erythroblastopenia diagnosed in the neonatal period or early infancy. The presence of IgM and IgG antibodies against parvovirus B19 is highly specific but their negativity is insufficient for the exclusion of a parvovirus B19 infection. Viral DNA testing by PCR method is the only reliable method available.

Three cases of massive fetomaternal hemorrhage presenting without clinical suspicion

Fetomaternal hemorrhage (FMH) is a common obstetrical occurrence most often associated with small volumes of blood transferred across the placenta. Fetomaternal hemorrhage leads to alloimmunization of Rh D-negative mothers, resulting in an increased risk of hemolytic disease of the newborn. Massive FMH involving volumes of blood greater than 30 mL can cause substantial fetal morbidity and mortality. Massive FMH may present with signs and symptoms such as decreased movement, sinusoidal heart rhythms, or fetal anomalies. We present 3 cases of clinically unexpected massive FMH of 206, 88, and 155 mL. The treating clinicians were unaware of any fetal or maternal signs or symptoms of FMH until contacted by the laboratory. These cases illustrate the necessity for FMH quantitation, even in the absence of clinical suspicion. Additional studies are needed to find better ways to identify these patients in advance. Development of criteria allowing identification of patients at risk would be of benefit to both mother and baby.

Autologous placental blood transfusion for the therapy of anaemic neonates

Almost 65% of all premature neonates with a birth weight <1,500 g receive at least one erythrocyte transfusion during their first weeks of life. In the present study, we examined the feasibility of autologous transfusions in neonates, using placental blood. Placental blood was obtained from 131 of 141 preterm and term infants using a special placental blood collecting system. Approximately 20 ml of placental blood per kilogram body weight could be harvested, irrespective of birth weight. One placental blood sample was contaminated with maternal erythrocytes; aerobe or anaerobe contamination was observed in any of the stored placental blood products (n = 119) after 35 days of storage. 19 of the 141 newborns needed allogeneic erythrocyte transfusions during the first 12 weeks of life. In 5 of these 19 patients, the amount of placental blood collected would have been enough to dispense with further allogeneic blood transfusions. After completion of the preclinical study, we transfused a total of 22 children, using autologous placental blood. 8 of the 10 infants with a birth weight between 1,000 and 2,000 g and 3 of 5 infants requiring surgical intervention directly after birth needed no further allogeneic blood transfusions. We, therefore, conclude that the collection and preparation of placental blood is feasible for clinical use. The target groups of neonates who are most likely to benefit are infants with a birth weight between 1,000 and 2,000 g and neonates requiring surgical intervention directly after birth.

Changes in haemoglobin levels in infants in Malawi: effect of low birth weight and fetal anaemia

OBJECTIVES

To examine the effect of low birth weight (LBW) and fetal anaemia (FA) on haemoglobin (Hb) patterns in infancy. To study the additional contribution of other risk factors known at birth. To examine the effect of iron supplementation during infancy on Hb levels.

METHODS

A stratified cohort of infants in Malawi (83 with LBW (< 2500 g), 111 with FA (cord Hb < 125 g/l), 31 with both LBW and FA, and 176 controls) was followed during infancy. Hb levels were measured at about 2, 4, 6, 9, and 12 months of age. Repeated measures models were used to describe the changes in Hb levels over time.

RESULTS

The mean Hb concentration in the control group was 95.5 g/l (95% confidence interval (CI) 92.5 to 98.5) at 2 months, 86.9 g/l (95% CI 84.4 to 89.4) at 9 months, and 898 g/l (95% CI 874 to 92.2) at 12 months. Differences between LBW infants and controls increased over time (difference at 12 months: 5.5 g/l (95% CI 1.3 to 9.7)). Infants with FA had borderline significantly lower Hb at 2 months (p = 0.07), but at 6 months their levels were similar to those of controls. The LBW infants and those with FA had the lowest Hb levels (difference from controls at 12 months 7.9 g/l). Parity, placental and maternal malaria at delivery, and sex significantly affected Hb levels after adjustment for LBW and FA. After iron supplementation, Hb significantly increased.

CONCLUSIONS

Antimalarial control and iron supplementation throughout pregnancy should be increased to reduce the incidence of infant anaemia and improve child development and survival.

Meta-analysis of controlled clinical trials studying the efficacy of rHuEPO in reducing blood transfusions in the anemia of prematurity

BACKGROUND

Recombinant human EPO (rHuEPO) has not gained broad acceptance in the treatment of the anemia of prematurity, because its efficacy in diminishing RBC transfusions is questionable. Meta-analysis was used to investigate the extent and reasons for variation in the results of published clinical trials.

STUDY DESIGN AND METHODS

Prospective controlled trials published from 1990 through 1999 were retrieved; 21 met the criteria for meta-analysis. Calculated across these studies were the summary OR of RBC transfusion in treated neonates as compared with controls and the summary mean difference between controls and treated neonates in the volume of RBCs transfused and the number of RBC transfusions per infant. Twelve study descriptors were examined as possible reasons for the variation in results.

RESULTS

Results of 21 eligible studies varied widely (p<0.001 for the Q test statistic), and this variation persisted in most analyses when studies were stratified by individual study descriptors. When the difference in volume of RBCs transfused was the outcome measure, variation was modest across the four studies with highly desired characteristics (i.e., high blindness and design quality scores, "conservative" transfusion criteria, and the majority of neonates weighing <1 kg at birth), and treatment with rHuEPO reduced RBC transfusions by an average of 11.0 mL per kg (p<0.001).

CONCLUSION

Benefit from rHuEPO is detected across high-quality studies using conservative RBC transfusion criteria. However, there is extreme variation overall in the findings of available trials, and-until this variation is accounted for-it is premature to recommend rHuEPO as standard treatment for the anemia of prematurity.

Delivery of a severely anaemic fetus after partial molar pregnancy: clinical and ultrasonographic findings

The incidence of a normal live fetus and a partial molar placenta is extremely rare. Although triploidy is the most frequent association, a fetus with normal karyotype can survive in cases of partial molar pregnancy. We report a case of partial molar placenta in which a live female baby was delivered at 32 weeks gestation by a 30-year-old woman. At the 18th week, ultrasonographic examination revealed a normal fetus with a huge, multicystic placenta. Chromosomal evaluation by amniocentesis revealed a normal female karyotype (46,XX), and serial biometric measurement of the fetus showed normal growth during pregnancy. There were no obstetric complications until the 32nd gestational week when preterm rupture of the membranes occurred. The electronic fetal heart beat tracing showed a repeated sinusoid pattern and late deceleration after admission. The patient underwent emergency Caesarean section and delivered a 1551-g, anaemic female baby with an Apgar score of 1, 4 and 6 at 1, 5 and 10 min, respectively. The baby recovered within 2 weeks after respiratory support and transfusion of packed red blood cells. Although anaemia is one of the risk factors that jeopardize the fetus in the case of partial molar pregnancy, termination is not indicated when the fetus is normal and no complications have occurred.

New molecular diagnostic tests for two congenital forms of anemia

Congenital hypoplastic anemias are a rare and heterogeneous group of disorders. This paper reviews new molecular diagnostic tests in two distinct forms of congenital anemias, anemia due to transplacental infection with B19 parvovirus and Fanconi anemia. In both instances, molecular assays making use of amplification of DNA by the polymerase chain reaction have been used to diagnose either a specific viral infection or gene mutation responsible for a disorder. Recognition of these entities has important prognostic and therapeutic implications.

Peripheral oxygenation and anemia in preterm babies

A measurement of tissue oxygenation may be a better marker of transfusion need than the Hb concentration. Peripheral fractional oxygen extraction, oxygen consumption, and oxygen delivery were measured noninvasively using near infrared spectroscopy in babies, some of whom were given blood transfusions. The above indicators of oxygenation were measured in 96 preterm babies. The decision to transfuse was based on a standard protocol. Transfusions were not considered necessary for babies in group 1 but were given to those in groups 2 (asymptomatic) and 3 (symptoms attributed to anemia). Hb and Hb fraction F (HbF) were measured in each baby. Oxygenation, Hb, and HbF measurements were made again 12-24 h after transfusion, and red cell volume (RCV) was calculated. Fractional oxygen extraction was significantly higher in symptomatic (0.43 +/- 0.06) but not asymptomatic (0.33 +/- 0.05) babies compared with control subjects (0.35 +/- 0.06). Oxygen consumption and oxygen delivery were similar in the three groups before transfusion. After transfusion the mean fractional oxygen extraction fell significantly in symptomatic but not in asymptomatic babies. There was no significant change in either oxygen consumption or oxygen delivery in symptomatic babies. The asymptomatic group had no change in oxygen extraction or oxygen consumption after transfusion, although oxygen delivery increased significantly. Fractional oxygen extraction correlated with HbF (n = 66, r = 0.49, p < 0.001) and RCV (n = 19, r = -0.48, p = 0.04) and there was a weak correlation with Hb (n = 94, r = -0.21, p = 0.04). Peripheral fractional oxygen extraction monitored noninvasively correlated with variables known to determine oxygen availability to the tissues, namely RCV and HbF, and was higher in babies with symptomatic anemia and decreased after transfusion.

The impact of fetal compromise on outcome at the border of viability

OBJECTIVE

Our goal was to evaluate the impact of fetal compromise on the outcome of borderline viable babies.

STUDY DESIGN

All 142 babies born in our hospital from 1990 to 1995 with a gestational age of 23 to 25 weeks were included. Fetal compromise was considered present if one of the following was documented: a major anomaly, congenital sepsis, chronic intrauterine infection, intrauterine drug exposure, congenital anemia, severe growth restriction, fetal acidosis, or cardiorespiratory and neurologic depression in the delivery room.

RESULTS

The 43 babies who had at least one cause of fetal compromise had a lower birth weight (p < 0.001), but there were no other differences in demographics or complications of prematurity. The survival rate was significantly better for babies free of fetal compromise (75% vs 33%, p < 0.001), particularly for babies born at 23 weeks of gestation (75% vs 6%, p < 0.001). For surviving babies free of fetal compromise, the outcome at 23 weeks was comparable to that at 24 to 25 weeks for major causes of long-term neurologic morbidity.

CONCLUSIONS

Like advancing gestational age and increasing birth weight, the absence of fetal compromise has a major beneficial impact on the outcome of borderline viable babies that might be important when decisions are made about the appropriate level of support.

Anemia and perinatal death result from loss of the murine ecotropic retrovirus receptor mCAT-1

The mCAT-1 gene encodes a basic amino acid transporter that also acts as the receptor for murine ecotropic leukemia viruses. Targeted mutagenesis in embryonic stem cells has been used to introduce a germ-line null mutation into this gene. This mutation removes a domain critical for virus binding and inactivates amino acid transport activity. Homozygous mutant pups generated from these cells were approximately 25% smaller than normal littermates, very anemic, and died on the day of birth. Peripheral blood from homozygotes contained 50% fewer red blood cells, reduced hemoglobin levels, and showed a pronounced normoblastosis. Histological analyses of bone marrow, spleen, and liver showed a decrease in both erythroid progenitors and mature red blood cells. Mutant fetal liver cells behaved normally in in vitro hematopoietic colony-forming assays but generated an anemia when transplanted into irradiated C.B.-17 SCID mice. Furthermore, reconstitution of the white cell compartment of SCID mice by mutant fetal liver cells was less complete than that observed with a mixed population of wild-type and heterozygous fetal liver cells. Primary embryo fibroblasts from mutant mice were completely resistant to ecotropic retrovirus infection. Thus, mCAT-1 not only appears to be the sole receptor for a group of murine ecotropic retroviruses associated with hematological disease but also plays a critical role in both hematopoiesis and growth control during mouse development.

Congenital anaemia after transplacental B19 parvovirus infection

We report three children with congenital anaemia after intrauterine infection with B19 parvovirus. All the fetuses developed hydrops fetalis that was treated by blood transfusion. After delivery the infants had hypogammaglobulinaemia. In all three, sera lacked B19 but viral DNA was found in bone marrow. All were treated with immunoglobulin. One child died and B19 was found in various tissues. In the other two cases, virus could no longer be detected after therapy but the patients remain persistently anaemic. Persistent B19 infection should be suspected in infants with congenital red-cell aplasia.

A study of the consequences of malarial infection in pregnant women and their infants

An outline is given of a field research study to be undertaken in Malawi to investigate the pattern and consequences of malaria in pregnancy and infants. The central question to be investigated is whether babies born to anaemic mothers in malarious areas are at increased risk of developing anaemia or altered risk for morbidity from malaria or develop anaemia in the first year of life. The framework for the case control and cohort study to be undertaken is outlined.

Expression of embryonic zeta-globin and epsilon-globin chains in a 10-year-old girl with congenital anemia

A 10-year-old Danish girl with congenital anemia is described. At birth, she had severe anemia and erythroblastosis and was transfused a number of times during the first year. The need for transfusions has since declined steadily. Her reticulocyte counts varied between 2% and 15%, and her bone marrow aspirate showed some dyserythropoietic features. Her hemoglobin F level was consistently elevated, up to as much as 41%. Her erythrocytes had a normal level of I antigen but an undetectable level of i antigen. Moreover, embryonic zeta-globin and epsilon-globin chains were present in some of her circulating erythrocytes. These findings may represent the manifestations of a new variant of congenital anemia.

Absent thumb, immune disorder, and congenital anemia presenting with hydrops fetalis

A patient is described who presented with severe congenital anemia, hydrops fetalis, immune disorder, and absent thumbs. No toxic, infectious, or metabolic cause was found to explain these symptoms. Immunologic and cytogenetic studies excluded several syndromes that combine radial ray anomalies with hematological involvement. After careful study of the literature, it is concluded that the disorder described here represents a new syndrome that can be added to a growing list of hematological-radial syndromes.

Congenital anemia, dyskeratosis, and progressive alopecia in Polled Hereford calves

A new syndrome of anemia, alopecia, and dyskeratosis was identified in Polled Hereford calves in this study. Cutaneous changes included hyperkeratosis and hair loss around the muzzle and ear margins, which progressed to a generalized alopecia and hyperkeratotic dermatitis. Histologically, orthokeratotic hyperkeratosis with dyskeratosis of epidermal and follicular keratinocytes was present. Alopecia was correlated with dyskeratosis of Huxley's layer and an increasing proportion of follicles in the telogen phase of the hair cycle. Dermatitis was characterized by a mild dermal mononuclear cell infiltrate and mild lymphocytic perivascular dermatitis. The anemia present at birth was nonprogressive and was classified as normochromic and normocytic to macrocytic. Reticulocytosis was absent, but bone marrow was markedly hyperplastic. Nuclear cytoplasmic asynchrony of the rubricyte and metarubricyte stages occurred in the bone marrow. Abnormal rubricyte nuclei and maturation arrest at the late rubricyte stage were common. Cytologic features of the erythroid series are similar to those of type I congenital dyserythropoietic anemia of human beings. Genealogic features suggest that this is a primary hereditary defect. The mode of inheritance, however, remains to be determined.

Exogenous iron overload in perinatal hemochromatosis: a case report

We report an infant with fatal neonatal liver disease in whom efforts to correct an associated unremitting anemia resulted in massive exogenous iron overload that was expressed as perinatal hemochromatosis (PH). Levels of iron and copper were elevated in multiple tissues. Echovirus subtype 9, recovered from the urine at age 3 weeks, may have been etiologic in the liver failure. PH is best viewed as a definable phenotype with an undefined genetic and/or environmental basis that emerges only in the context of severe perinatal liver disease. The absence of hemosiderin in splenic and bone marrow reticuloendothelial (RE) cells of our patient suggests an important role for RE cell dysfunction.

Placental haemangioma associated with acute fetal anemia in labour

A case of pregnancy complicated by a placental hemangioma is presented. This was unassociated with any of the complications commonly coexistant with this tumor, and presented with fetal anemia due to a fetomaternal transfusion.

Congenital anemias in Macau

The implementation of a Primary Health Care system in Macau has created the need to study the prevalence of Congenital Anemias in the population to facilitate the planning of measures needed for their control. Blood samples from 3815 women attending the antenatal clinics were screened for beta-thalassemia using MCH values as the preliminary test, followed by quantitation of Hb A2 and Hb F. Isoelectric-focusing was used to screen 1091 cord blood samples for the presence of Hb Bart's. The prevalence of alpha- and beta-thalassemia carriers was found to be 6.2% and 3.6%, respectively.

Chromosome changes in human monocytic cell lines with in vitro spontaneous malignant transformation

Serial chromosome studies were performed on four monocytic cell lines established from bone marrow samples of patients suffering from hematopoietic disorders other than leukemia. A spontaneous in vitro transformation towards a malignant phenotype has been found to be related to the karyotype evolution. The correlation between the chromosome changes of these cell lines and those described in human cancer and leukemia is discussed.

[Thiamine-dependent anemia and thrombocytopenia, insulin-dependent diabetes mellitus and sensorineural deafness--case report and review]

Report of an 3 1/2 year old girl who because of resistant anemia and thrombocytopenia received blood transfusions since her third month of life. 15 months later she developed diabetes mellitus. Sensorineural deafness was noticed since her third year of life. Daily 25 mg thiamine prevented anemia and thrombocytopenia. The syndrome is compared with the 5 published cases of world literature.

Diamond-Blackfan syndrome in adult patients

Two adults with pure red cell aplasia are described. No extrinsic etiologic mechanisms were identified. Evidence of anemia was long-standing and varied in severity. Musculoskeletal abnormalities (webbed neck, Sprengel's and Klippel-Feil deformities, and hand abnormalities) were similar to those seen in the congenital form of red cell aplasia (Diamond-Blackfan syndrome). As in the congenital variety, adrenal cortical steroids resulted in hematologic repair. These observations suggest that congenital (Diamond-Blackfan) pure red cell aplasia may be first recognized in adulthood and that steroids provide a potential therapeutic modality.

Ferrochelatase deficiency of the bone marrow in a syndrome of congenital microcytic anaemia with iron overload of the liver and hyperferraemia

Ferrochelatase deficiency of the bone marrow was found in 2 sisters with a syndrome of congenital hypochromic anaemia, hyperferraemia and heavy iron deposits in the liver.

[Sea-blue histiocytosis. I. Cytological study]

Traumatic blindness is a well recognized entity with a guarded prognosis. Previous studies have variously reported the incidence of concomitant optic canal fractures and response to surgical therapy. With the advent of CT scanning, a new technique for study of these severely injured patients has become available. Over a period of 20 months, optic foramen fractures were demonstrated in 10 such patients using finely collimated, high-resolution CT scans. Fractures were easily classified by location, relation to the optic nerve assessed, and associated facial injuries imaged. The technique is easy, rapid, and superior to polytomography in this setting. Possible implications for therapy are discussed.