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PubMed1976

Oncogenic response of rats with x-ray-induced microcephaly to transplacental ethylnitrosourea.

The relation of congenital malformations to tumor development was examined. Pregnant Sprague-Dawley rats were given 200 rads of X-rays on the 15th or 16th day of gestation and injections of 10 mg ethylnitrosourea (ENU)/kg 1-4 days later, or they were irradiated or injected only. Surviving weanlings that had been irradiated had micrencephaly and other malformations. Offspring exposed to ENU only had no external deformities. By 15 months of age 16.7% of the offspring exposed to X-rays and ENU prenatally had developed neurogenic tumors, whereas 62.2% of those exposed to ENU alone had developed tumors. Those only irradiated had no tumors. Both of the former groups developed oligodendrogliomas, mixed gliomas, ependymomas, and schwannomas, but the first manifestations of tumors occurred later in the group receiving the combined treatment. This delay persisted furing the subsequent period of the study.

Animals↗
PubMed1983

Congenital dysautonomia. A case with a posterior interhemispheric cyst and microcephaly.

A non-Jewish child had a congenital sensory and autonomic neuropathy, cerebral hypoplasia, and a posterior interhemispheric cyst. The clinical findings, neuropathologic changes in the spinal cord, the peripheral nerves, the sensory and autonomic ganglia, as well as sural nerve morphometry, showed similarities, but also differences from familial dysautonomia and hereditary sensory neuropathy, type IV. The relationship of this case to hereditary sensory neuropathies and dysautonomias is discussed, and it is suggested that this is an atypical form of familial dysautonomia with coincidental developmental abnormalities.

Brain Diseases↗
PubMed2003

Role of nutrition in pregnancy with phenylketonuria and birth defects.

OBJECTIVE: The maternal phenylketonuria (PKU) syndrome is caused by high blood phenylalanine (Phe) levels during pregnancy, leading to a host of birth defects, especially microcephaly and congenital heart disease (CHD). For finding whether the maternal PKU syndrome could be prevented, an international collaborative study was organized to evaluate treatment with a Phe-restricted diet. Blood Phe levels, maternal weight gain, and nutrient intakes during pregnancy were evaluated as to their effect on the rate of microcephaly and CHD in the offspring. METHODS: The study was a prospective, longitudinal effort aimed at lowering blood Phe during pregnancy. Women were enrolled at time of referral for pregnancy. Nutrient intake analysis, which serves as the basis for this report, was available from 251 pregnancies. Subjects were stratified by blood Phe control of < or =600 micromol/L by 8 weeks gestation or >600 micromol/L by 8 weeks gestation. Outcome of these pregnancies was correlated to blood Phe levels, weight gain, and nutrient intake. RESULTS: The study goal was to attain blood Phe levels of 120 to 360 micromol/L 3 months preconception; however, this goal was achieved by only a limited number of patients. Therefore, the data presented were based on blood Phe control < or =600 micromol/L or >600 micromol/L by 8 weeks of gestation. Blood Phe control of < or =600 micromol/L by 8 weeks of gestation was attained by 86 (34.3%) of the 251 women in this study, whereas the other 165 women had blood Phe control >600 micromol/L by 8 weeks of gestation. Of the 251 offspring, 166 were born with normal head circumference and 85 were born with microcephaly (<2 standard deviations below normal). Women with blood Phe >600 micromol/L at 8 weeks of gestation included 78 (92%) of the 85 infants with microcephaly compared with 8% in the group of women who had blood Phe levels < or =600 micromol/L. Weight gain during pregnancy was related to the rate of microcephaly. The highest occurrence of microcephaly (58%) was found in the pregnant women who gained <70% of recommended weight gain. Stepwise logistic regression analysis was used to determine factors associated with microcephaly. Significant factors included higher blood Phe levels when off diet, higher average Phe exposure during the pregnancy, low prepregnancy weight, poor weight gain during the pregnancy, and lower intake of protein and higher iron intake during the pregnancy. Infants with CHD were found only in the group of women who had blood Phe levels >600 micromol/L by 8 weeks of gestation. There was a higher rate of CHD in the offspring who were born to women who consumed <50% of the recommended intake of protein in the first trimester. The main source of protein for women with PKU is the medical food; therefore, when protein intake was low, vitamin and mineral intakes were also inadequate. CONCLUSIONS: The data indicate that blood Phe control and how soon it is attained during pregnancy with PKU is important. Normal pregnancy weight gain should be encouraged to reduce microcephaly. Adequate protein and vitamin intakes early in pregnancy may have a protective effect for the prevention of CHD, even if blood Phe is elevated. The rate of microcephaly and CHD may be reduced if nutrient intake is optimal while attempting to control blood Phe levels.

Female↗
PubMed1999

[Embryonic pathology caused by maternal phenylketonuria. A cause of underdiagnosed mental retardation. A report of 8 cases].

OBJECTIVE: Maternal phenylketonuria (MPKU) is characterized by intrauterine growth retardation, microcephaly, congenital malformations (mainly cardiac defects), dysmorphic facial features and mental retardation. There are women of child-bearing age that do not know that they are affected by phenylketonuria (PKU) and their pregnancies could result in damage to the fetus expressed as different neurological and congenital abnormalities. PATIENTS AND METHODS: We report 8 patients from 4 families. The first family had two offspring with intrauterine growth retardation, microcephaly and psychomotor retardation. The second family consisted of a daughter with mental retardation (without further data), a second baby which died during the first day of life, and a third child which died at 7 months of age with cardiac defects, microcephaly and dysmorphic features. Another child had intrauterine growth retardation, microcephaly psychomotor retardation, dysmorphic features and cardiac defects (coarctation of the aorta and subaortic stenosis). The third family had a son with microcephaly and mental retardation. The fourth family had a boy that died at 3 weeks of age with microcephaly, dysmorphic facial features, congenital heart disease (mitral atresia and septal defects) and Meckel diverticulum and a girl 5 years of age with intrauterine growth retardation, microcephaly and mental retardation. In all cases the mothers were unaware that they were affected by PKU and had mild intellectual defects. Two of them had PKU phenotypes. CONCLUSIONS: The offspring of PKU mothers untreated during pregnancy are affected by characteristic embriopathies related to the level of phenylalanine during pregnancy. In Spain, massive routine newborn screening was introduced around 1980-1985 and at present there are women of child-bearing age and are unaware that they are affected by the disease and that their pregnancies may result in fetal damage, as we demonstrate in these 8 patients. When faced with women with mental handicap or with antecedents of offspring with mental retardation, cardiac defects, microcephaly or intrauterine growth retardation, the determination of maternal phenylalanine concentrations is recommended. These teratogenic pathologies tend to disappear, but for the moment it is necessary to prevent this teratogenicity. The diagnosis is easy, avoids complementary exams, may help family studies and allows the implementation of dietary restriction during the subsequent pregnancy that would prevent fetal damage.

Child, Preschool↗
PubMed1996

Fetal ultrasonography in maternal PKU.

Maternal phenylketonuria (PKU) is teratogenic and results in birth defects that include microcephaly, mental retardation, congenital heart disease, and intrauterine growth retardation. Treatment with a low phenylalanine diet can prevent or reduce the severity of the complications. Optimal benefit, however, requires frequent monitoring with fetal ultrasonography as a critical element. We have studied ultrasonography in 39 pregnancies enrolled in the Maternal PKU Collaborative Study and followed at our centre. First-trimester examinations in 24 pregnancies resulted in the discovery of non-viability in five. In each, this led to discontinuation of the difficult and expensive diet. Among the 33 pregnancies with second-trimester evaluation, congenital heart disease was identified in five. Two of these pregnancies were terminated. Microcephaly as determined by biparietal diameter (BPD) was identified in the second trimester in only one of nine fetuses who had microcephaly at birth. Among 20 pregnancies with third-trimester ultrasound, fetal microcephaly was identified by BPD in three of seven who had birth microcephaly. We conclude that fetal ultrasonography in maternal PKU is valuable during the first trimester in identifying non-viable pregnancies and determining gestational age and is also valuable during the second trimester in identifying congenital heart disease and perhaps other major anomalies, but not in identifying fetal microcephaly. Third-trimester ultrasound seems to be of limited usefulness.

Female↗
PubMedDate not supplied

Cerebral atrophy following shaken impact syndrome and other non-accidental head injury (NAHI).

PURPOSE OF THE STUDY: To determine the frequency of cerebral atrophy and microcephaly in a group of children with sequential MRI brain scans after surviving a non-accidental head injury (n = 16). METHODS: Serial head circumference measurements (OFC) were extracted and plotted on standard growth charts for each child retrospectively to determine the frequency of secondary microcephaly. Cerebral atrophy was diagnosed and quantified by measurement of the ventricular/cortical ratio on coronal images of the sequential scans. RESULTS: Acquired microcephaly was found in 15 children (93.8%) over a median follow-up period of 67.93 weeks. There was a significant reduction in the median Z-score for the OFC at the most recent follow-up when compared with that at presentation (p < 0.001, Wilcoxon Signed Rank Test). Cerebral atrophy was found to be the cause of the microcephaly in eight of the 15 children and was evident as early as 9 days after presentation. CONCLUSION: A large proportion of the cohort (93.8%) develops acquired microcephaly after an inflicted head injury and cerebral atrophy is responsible in half of these cases.

Atrophy↗
PubMed2000

Clinical presentation and mutation identification in the NBS1 gene in a boy with Nijmegen breakage syndrome.

Nijmegen breakage syndrome (NBS) is a rare autosomal recessive disorder which belongs to the group of inherited chromosomal instability syndromes. The clinical characteristics include severe microcephaly, a dysmorphic facies, and immunodeficiency with predisposition to malignancies. While the cellular characteristics of ataxia teleangiectasia (AT) and NBS are similar, the clinical findings are quite distinct. NBS patients show characteristic microcephaly, which is rare in association with AT and they do not develop ataxia and teleangiectasia. Recently, the gene mutated in NBS has been identified. Here we report a 5-year-old Bosnian boy with severe microcephaly. Because of multiple structural aberrations involving chromosomes 7 and 14 typical for AT (MIM 208900) and NBS (MIM 251260), AT was diagnosed. We suggested the diagnosis of NBS because of the boy's remarkable microcephaly, his facial appearance, and the absence of ataxia and teleangiectasia. DNA analysis was performed and revealed that the boy is homozygous for the major mutation (657de15) in the NBS1 gene. This finding confirms the diagnosis of NBS in our patient and offers the possibility to perform a most reliable prenatal diagnosis in a further pregnancy.

Adult↗
PubMed1979

[Recessive microencephaly linked to the X chromosome].

A family with X-linked recessive microcephaly is reported. As patients there were found 8 men or boys respectively out of 3 generations, all of them being related by their mentally healthy mothers. Besides microcephaly the patients showed growth retardation and obesity. Some of them, in addition, had various anomalies as inguinal or umbilical hernias, cryptorchism, tapering fingers, contractures, deeply rooted thumbs and club-feet. There were no hints for a metabolic defect or a chromosomal aberration. The dermatoglyphics could be investigated in 5 patients and showed in all of them a shifting of the axial triradius into the distal position t'. Comparing the own findings with case reports on X-linked microcephalies, the above mentioned family was found not to correspond to any of these observations. It is assumed that in this family, a new disease has occurred which until now has not yet been described, so that the X-linked microcephalies seem to be a heterogenous group of disease from the genetic point of view.

Adult↗
PubMed1994

Toluene embryopathy: clinical delineation and developmental follow-up.

OBJECTIVE: To expand the phenotype of toluene embryopathy. METHOD: Review of case records of 35 deliveries with antenatal exposure to toluene. Six children were examined and their features are compared with previously reported cases. RESULTS: There were three perinatal deaths. Of the survivors, review of available data revealed a high incidence of prematurity (42%), low birth weight (52%), and microcephaly (32%). Birth weight, length, and head circumference and gestational length were significantly less than a control group closely matched for gender, race, and socioeconomic status. Follow-up pediatric evaluation revealed growth retardation (46% < 5th percentile for weight, 38% < 5th percentile for height), microcephaly (46%), and developmental delays (38%). Maternal toluene abuse of 4 or more years was positively correlated with weight < 5th percentile and microcephaly in childhood. The six children examined demonstrated many previously described features of toluene embryopathy including microcephaly, narrow bifrontal diameter, short palpebral fissures, hypoplastic midface, wide nasal bridge, abnormal palmar creases, and blunt fingertips. Only one of the six children examined had antepartum exposure to alcohol as well as toluene. CONCLUSION: In utero exposure to toluene seems to be associated with teratogenicity in the developing fetus. A preliminary picture of toluene embryopathy is now emerging.

Abnormalities, Drug-Induced↗
PubMed2006

Molecular evolution of the brain size regulator genes CDK5RAP2 and CENPJ.

Primary microcephaly is a developmental defect of the brain characterized by severely reduced brain size but an absence of other overt abnormalities. Mutations in several loci have been linked to primary microcephaly. The underlying genes for two of these were recently identified as CDK5RAP2 and CENPJ. Here, we focus on CDK5RAP2 and show that the protein evolutionary rate of this gene is significantly higher in primates than rodents or carnivores. We further show that the evolutionary rate within primates is particularly high in the human and chimpanzee terminal branches. Thus, the pattern of molecular evolution seen in CDK5RAP2 appears to parallel, at least approximately, that seen in two other previously identified primary microcephaly genes, microcephalin and ASPM. We also briefly discuss CENPJ, which similarly exhibits higher rate of protein evolution in primates as compared to rodents and carnivores. Together, the evolutionary patterns of all four presently known primary microcephaly genes are consistent with the hypothesis that genes regulating brain size during development might also play a role in brain evolution in primates and especially humans.

Animals↗