Placental mesenchymal dysplasia associated with fetal overgrowth and mosaic deletion of the maternal copy of 11p15.5

Placentae with mesenchymal dysplasia (PMD) are typically larger than average and show cystic areas on ultrasonography. Fetal outcomes are variable and are often associated with growth restriction. However, enigmatically, some associated fetuses show signs of Beckwith-Wiedemann syndrome (BWS). PMD has recently been shown to result from androgenetic (complete paternal uniparental disomy) chimerism in the placenta in pregnancies that were associated with some fetal growth restriction. Cases of PMD associated with overgrowth have not previously been investigated molecularly. We present a case of focal PMD associated with a male fetus showing overgrowth with an enlarged heart, marked fetal ascites and intrauterine fetal death at 34 weeks, but no other BWS manifestations. Mosaicism for an unbalanced translocation leading to deletion of the maternal copy of the BWS region on 11p15.5 and partial duplication of 17q was observed in placenta, but not fetal samples. While the placental findings of PMD can be caused by an unbalanced dosage of genes in 11p15.5 alone, fetal growth parameters appear to depend on the underlying mechanism and likely also the level and distribution of abnormal cells.

Hemifacial microsomia: progress in understanding the genetic basis of a complex malformation syndrome

Hemifacial microsomia (HFM) is a common birth defect involving first and second branchial arch derivatives. The phenotype is extremely variable. In addition to craniofacial anomalies there may be cardiac, vertebral and central nervous system defects. The majority of cases are sporadic, but there is substantial evidence for genetic involvement in this condition, including rare familial cases that exhibit autosomal dominant inheritance. As an approach towards identifying molecular pathways involved in ear and facial development, we have ascertained both familial and sporadic cases of HFM. A genome wide search for linkage in two families with features of HFM was performed to identify the disease loci. In one family data were highly suggestive of linkage to a region of approximately 10.7 cM on chromosome 14q32, with a maximum multipoint lod score of 3.00 between microsatellite markers D14S987 and D14S65. This locus harbours the Goosecoid gene, an excellent candidate for HFM based on mouse expression and phenotype data. Coding region mutations were sought in the familial cases and in 120 sporadic cases, and gross rearrangements of the gene were excluded by Southern blotting. Evidence for genetic heterogeneity is provided by the second family, in which linkage was excluded from this region.

Yellow nail syndrome presenting as non-immune hydrops: second case report

The yellow nail syndrome is characterized by slowly growing yellow discolored nails and lymphoedema, with onset generally after puberty. We report on a newborn infant who, at 23 weeks, was found to have hydrops on antenatal ultrasonography and bilateral chylothorax at delivery. His mother has the yellow nail syndrome, with typical nail changes, and bronchiectasis. There seemed to be no other etiology for the non-immune hydrops, and this is the second documented case of the prenatal manifestation of this condition.

Syndrome of microcephaly, microphthalmia, cataracts, and intracranial calcification

We present two sisters with microcephaly, developmental delay, marked microphthalmia, congenital cataracts, cerebral and cerebellar hypoplasia, and intracranial calcification. No evidence of intrauterine infection was found. There have been previous reports of microcephaly, intracranial calcification, and an intrauterine infection-like autosomal recessive condition, but the sibs in this report appear to represent a more severe form of such a condition or a previously undescribed entity.

Siblings with a syndrome of hydrocephalus with patent aqueduct, growth retardation and associated anomalies

We report on male siblings with hydrocephalus with associated abnormalities including growth retardation, midline cleft palate and bilateral 'fisting' of the hands, providing evidence for a familial syndrome of hydrocephalus and associated anomalies.

What constitutes cerebral palsy?

Cerebral palsy (CP) is a term of convenience applied to a group of motor disorders of central origin defined by clinical description. It is not a diagnosis in that its application infers nothing about pathology, aetiology, or prognosis. It is an umbrella term covering a wide range of cerebral disorders which result in childhood motor impairment. The precise inclusion criteria vary with the objectives for using the term. For meaningful comparison of rates of CP, as performed by and between CP registers, it is important that the rates should be generated using the same criteria. As generally understood there must be motor impairment, and this impairment must stem from a malfunction of the brain (rather than spinal cord or muscles). Furthermore, the brain malfunction must be non-progressive and it must be manifest early in life. For the purposes of comparisons of rates across time even when the condition meets all the above criteria, it must not historically have been excluded from the category of CP. This paper addresses the problem of standardizing the inclusion criteria for selecting people included on CP registers with particular reference to this last criterion.

Further evidence for preaxial hallucal polydactyly as a marker of diabetic embryopathy

Maternal diabetes has an established aetiological link with developmental abnormalities, and the prevalence of major congenital malformations in the offspring of affected women is approximately 4-8%, compared to the general population risk of about 3%. Hallucal polydactyly, particularly with an unusual proximal placement of the extra digit, has been reported as a distinctive anomaly in diabetic embryopathy. We report on a child of a diabetic mother with this unusual form of hallucal polydactyly, together with other skeletal anomalies, confirming that this malformation is a useful clinical marker for the diagnosis of diabetic embryopathy.

Further evidence for a syndrome of "apple peel" intestinal atresia, ocular anomalies and microcephaly

We report on a male child with "apple peel" atresia, associated with microcephaly, with subsequent hydrocephalus, short stature, moderate global developmental delay and ocular abnormalities. A similar phenotype was previously reported by Stromme et al. in 1993 in female siblings, and this description of another affected individual provides further evidence for this being a distinct syndromic entity.

Familial hemifacial microsomia due to autosomal dominant inheritance. Case reports

Hemifacial microsomia is a rare dentofacial anomaly which is regarded as a separate entity to Goldenhar syndrome and primarily affects the structures of the first branchial arch. It has a heterogeneous aetiology and tends to occur sporadically, though positive family histories have been reported. This paper reports on individuals in two generations of a family that has overlapping features of hemifacial microsomia and Goldenhar syndrome segregating as an autosomal dominant condition.

Description of the effects of a single gene which inhibits the normal metabolic response of newborn lambs to exogenous noradrenaline

A group of newborn Scottish Blackface lambs previously selected for low cold resistance failed to show the normal metabolic response to subcutaneous injection of exogenous noradrenaline. A subsequent study showed this failure to be due to a single major gene. Further studies on the thermogenic and physiological responses and on the inheritance of the trait, are described here. Two intercross matings between non-responders produced responder lambs indicating that the gene is not recessive. The increases in metabolic rate and rectal temperature after injection of noradrenaline were much greater in responder than in non-responder lambs (P less than 0.001), as were the increases in heart rate and respiration rate (P less than 0.001). Dissected brown adipose tissue from non-responders was apparently normal and indistinguishable from brown adipose tissue from responders. Although there was no apparent effect of the gene on birthweight or survival, survival under normal field conditions may be affected.

Genetic aspects of cold resistance and related characters in newborn Merino lambs

Resistance to body cooling and rate of recovery from induced hypothermia were measured in 287 single, newborn Merino lambs from 24 different sire families, using a water bath test in which partly immersed lambs were progressively cooled. Birth weight, birthcoat type (fine-hairy) and skin thickness were recorded at the time of test. There was an unexpected occurrence of congenital goitre, the incidence and severity of which was estimated by manual palpation of the thyroid gland. Heritability (� s.e.) of cold resistance (CR), estimated by paternal half-sib analysis, was 0.70 � 0.25. Sex of lamb, type of weather, time of test, Fecundin treatment and age of ewe were fitted in the model as fixed effects but none were significant. Other heritable traits (h2 � s.e.) included birthweight (0.50 � 0.22), birthcoat grade (0.61 � 0.24), coat depth (0.62 � 0.24), skin thickness (0.35 � 0.19) and the severity of goitre (0.21 � 0.16). Significant genetic correlations (r �s.e.) between cold resistance and other traits were: birthweight, +0.76 � 0.18; birthcoat grade, +0.56 � 0.24; birthcoat depth, +0.56 � 0.24; skin thickness, +0.51 � 0.27; goitre, -0.58 � 0.40. Most of the corresponding phenotypic correlations were small. Goitre did not affect CR significantly, despite the genetic correlation between them. Heritability of CR, further adjusted for the effects of birthweight, birthcoat grade and depth, and skin thickness as covariates, was 0.55 � 0.23. About 40% of the variation in CR was accounted for by fitting fixed effects and covariates, but significant sire effects remained. Rate of recovery from hypothermia was not heritable and it was unrelated to any other variable except goitre, which tended to be associated with slower recovery (rp = 0.18). It was concluded that genetic selection for increased CR would succeed but would promote birthcoat hairiness unless a corrective selection index was used. The relationship between birthcoat type and CR was considered to be mediated by genes affecting both coat type and CR, not primarily by a direct effect of coat insulation.

The inheritance of non-response to noradrenaline in newborn Scottish blackface lambs

The normal response to injection of noradrenaline (NA) in newborn lambs is an increase in metabolic rate and rectal temperature, due to the stimulation of non-shivering thermogenesis. In a previous study 6 out of 7 lambs born to a sire previously selected for low resistance to cold failed to show this characteristic response and were termed non-responders. The sire, 2 of his male offspring and 6 sires selected randomly from the flock were mated to several ewes and the response to NA stimulation recorded in 116 newborn lambs. Control sires produced only normal responder lambs whereas the remaining sires all produced both responder and non-responder lambs. The proportion of non-responders was not significantly different from 0·50, which is consistent with a dominant major gene. Analysis of the quantitative traits, peak metabolic rate and peak rectal temperature following NA injection confirms that a major gene is segregating in the study population, but is unable to distinguish between dominant and recessive modes of inheritance. Absence of non-responders in other studies suggests that dominance is more likely. This new genetic resource could aid our understanding of brown adipose tissue metabolism and the effect of catecholamines on metabolic pathways.

The effects of cold exposure of pregnant sheep on foetal plasma nutrients, hormones and birth weight

1. Five pregnant sheep, with indwelling catheters positioned for withdrawal of maternal right-atrial and foetal arterial blood, were exposed for 2 h to neutral and to cold (-10 and wool-clipped) environmental temperatures. Acute maternal cold exposure increased the concentrations of glucose, glycerol and non-esterified fatty acids in maternal plasma and increased the concentration of glucose in foetal plasma, but not glycerol or non-esterified fatty acids. The concentration of corticosteroids in maternal plasma increased. The concentration of corticosteroids in foetal plasma did not change but the concentration of insulin increased. 2. Thirteen pregnant sheep were housed at thermoneutrality and thirteen similar sheep, fed the same amount of food, were clipped and exposed to cold during the last 5-6 weeks of pregnancy. Chronic maternal cold exposure increased the birth weight of both single and twin lambs. 3. It is concluded that exposure of pregnant sheep to cold can alter the partition of some nutrients between mother and foetus in favour of the foetus, and it is suggested how this may be brought about.

Hypothermia in newborn lambs induced by experimental immersion in a water bath and by natural exposure outdoors

A progressively cooling water bath technique was developed to measure resistance to body cooling in newborn lambs. Cold resistance, defined as the time taken to reduce rectal temperature to 35 degrees C, was measured in 429 lambs of 12 different breeds individually immersed in a water bath. Two alternative procedures were used with water temperature falling from 37 degrees C to 12 degrees C or from 25 degrees C to 10 degrees C. In lambs tested twice the repeatability of cold resistance was high: 0.95 and 0.81 respectively in the two types of test. There were clear breed differences in cold resistance, some breeds being up to three times more resistant than others. Health was unimpaired by treatment and preweaning mortality was not affected. Ten of the breeds represented in water bath tests were also used for measurements of rectal temperature 1 h after birth in the field. There was some similarity in the breed rank order for ability to resist hypothermia in the field and in the water bath. Water bath tests of hypothermia in lambs could facilitate genetic selection for improved perinatal survival in the field.

Habituation and acclimatization of sheep to cold following exposures of varying length and severity

1. Male and female Scottish Blackface sheep were shorn and exposed for 2 weeks either to a thermoneutral temperature (+30 degrees C), to chronic cold (+8 degrees C) or to +30 degrees C interrupted by daily short cold shocks (-10 degrees C). During and at the end of these conditioning treatments, the sheep also received two acute cold exposures (-20 degrees C, 4 m.p.h. wind for 2-8 hr) 1 week apart. Some of these sheep and a fourth (control) group, were subsequently re-shorn and slowly cooled to +8 degrees C.2. Resting metabolism and the metabolic response to cooling (both inferred from heart rates) were increased by previous chronic cold treatment. Resistance to body cooling (measured during acute cold exposure) was generally increased by both chronic and acute cold, and non-shivering thermogenesis was probably induced in the female sheep. These effects were defined as acclimatization.3. In contrast, cold shocks reduced the subsequent metabolic response to cold and encouraged facultative body cooling. This pattern of response (defined as habituation) therefore caused greater thermolability.4. Habituation and acclimatization were antagonistic. Habituation was removed by acute cold exposure and, conversely, acclimatization was inhibited by short cold shocks.5. There were sex differences in response but these were confounded by probable differences in insulation and in body condition (males thinner).6. It was concluded that the induction of different forms of adaptation depended on the length, severity and frequency of cold exposures. Habituation to whole body cold exposure apparently involved central nervous system centres normally receiving peripheral cold stimuli.

Developmental Morphology of the Skin and Hair Follicles in Normal and in “Ragged” Mice

Ragged (Ra) is a semi-dominant mutant gene which was first reported by Carter & Phillips (1954). The adult morphology, the genetics, and the embryology of the mutant mice were described by Slee (1957 a, b). It was found that adult ragged heterozygotes (Ra+) had sparser coats than normal, many of their hair follicles being incompletely developed and non-functional. Ragged homozygotes (RaRa) were almost naked. Most of their pelage hair follicles were either absent, or abnormal and non-functional. Ra+ embryos could be identified from 16 days' gestation by the retardation of their sinus hair-growth. RaRa embryos were characterized from 13 days' gestation by the occurrence of a generalized subcutaneous oedema which persisted until birth, and also by retardation in the development of their sinus hairs and follicles. Pelage follicle primordia appeared at the normal time (14 days' gestation) in Ra+ and RaRa embryos but subsequently developed slowly in RaRa embryos, especially when the oedema was pronounced.