Tetrasomy 12p (Pallister-Killian syndrome): difficulties in prenatal diagnosis

Purpose  

We report a rare case of Pallister-Killian syndrome diagnosed prenatally with increased nuchal translucency during screening for trisomy 21.     

A further prenatal diagnosis of mosaic tetrasomy 12p (Pallister-Killian syndrome)

A case of mosaic tetrasomy 12p was detected in amniotic fluid cell cultures from a 28-year-old woman referred to us at 26 weeks' gestation because of hydramnios. The fetus was shown on ultrasonography to have an omphalocele and a short femur length. Labour was induced at 32 weeks. An infant with multiple congenital anomalies was delivered and died after 10 min. The diagnosis of i(12p) or Pallister-Killian syndrome was confirmed cytogenetically in fibroblast and lymphocyte cultures. Increased LDH-B activity was demonstrated in fibroblasts.     

Contribution of 3D ultrasound and fetal face studies to the prenatal diagnosis of Pallister-Killian syndrome

Background.?Pallister-Killian syndrome (PKS) is a multiple malformation syndrome caused by a chromosomal abnormality in which the presence of four copies of the short arm of chromosome 12 results in severe mental retardation. Cytogenetic diagnosis is particularly difficult due to the specific tissue distribution of the abnormality. PKS may be suspected based on the prenatal ultrasound detection of polyhydramnios and diaphragmatic hernia, possibly associated with rhizomelic micromelia.

Method and results.?We report here a case of PKS in which the 3D ultrasound examination of facial features after prenatal PKS diagnosis showed signs suggestive of the syndrome.

Conclusion.?A detailed 3D examination of the fetal face may help to guide diagnosis, particularly when the only sign detected on ultrasound is polyhydramnios, as in the case reported here.     

Retrospective diagnosis of Pallister-Killian syndrome by CGH array

OBJECTIVE AND METHODS: We report a girl presenting with a polymalformation syndrome. Despite a normal karyotype on peripheral lymphocytes and the unavailability of cultured fibroblasts, a tetrasomy 12p was identified on pulmonary DNA extracted from a postmortem biopsy, by use of comparative genomic hybridization (CGH) and confirmed by CGH array. The clinical picture of our patient was consistent, but not specific of the diagnosis of Pallister-Killian syndrome. She presented with the association of antenatal polyhydramnios, craniofacial dysmorphic features, skeletal abnormalities, and a congenital cardiopathy. CONCLUSION: We discuss the usefulness of CGH and CGH array in prenatal and constitutional cytogenetics.     

Robinow's syndrome: prenatal diagnosis

The prenatal diagnosis of Robinow's syndrome was accomplished in our case by measuring the length of the long bones and the ulna/humerus ratio. Although the prenatal sonographic appearance did not show the typical 8-week fetal face, pathological findings confirmed this particular feature. In view of the strongly suggestive family history, the authors consider the possible mechanisms of genetic inheritance.     

Ovarian remnant syndrome: difficulties in diagnosis and management

Ovarian remnant syndrome should be considered in the differential diagnosis of pelvic pain with a mass in a patient who has had extirpative surgery. Although rarely reported in the literature, it is probably much more prevalent than is suspected. Most commonly, the initial surgery was performed for endometriosis or pelvic inflammatory disease, with incomplete excision of the ovaries. Surgical excision of the ovarian remnant, the definitive treatment, is itself difficult, and is often attended by serious complications. Medical therapy is empiric, and hormonal manipulation may help prevent recrudescence. Three cases are reported, their pathology and the literature is reviewed.     

Alagille syndrome: prenatal diagnosis and pregnancy outcome

The Alagille syndrome (AGS) is a multisystem autosomal dominant condition. In this case report, we describe a pregnant woman with this unusual disorder, in whom serial fetal sonography revealed severe pulmonary stenosis and progressively severe intrauterine growth retardation, suggesting that the fetus also had AGS, a diagnosis which was confirmed postnatally. In this report, the potential complications for pregnancy, labor and delivery when both mother and fetus are affected with AGS are described.     

Norman-Roberts syndrome: prenatal diagnosis and autopsy findings

We report on the autopsy findings of a male fetus in the 27th week of gestation with Norman-Roberts syndrome. The unaffected parents are first cousins and have a five-year-old child with a low, sloping forehead, broad and prominent nasal bridge, widely set eyes, severe psychomotor retardation, and an agyric cortex. Prenatal diagnosis showed a small head at the 25th week of gestation. At this time, a slowing-down of the growth of the sonographic measurements of the biparietal diameter and head circumference was found. Both the biparietal diameter (57 mm, <5th percentile) and the head circumference (207 mm, <5th percentile) showed a delay of at least two weeks in comparison with other non-cephalic somatometric parameters, that were normal for the gestational age (femur length: 46 mm=median value). After termination of pregnancy, post-mortem examination showed a normotrophic fetus with microcrania and marked microcephaly (brain weight: 50 g), low, sloping forehead, broad and prominent nasal bridge, and widely set eyes. The cerebral hemispheres displayed an almost completely smooth surface with poorly defined sylvian fissures and failure of operculization of the insula. Microscopic examination showed a predominantly four-layered cortex (lissencephaly type I). Karyotype was normal and in situ hybridization did not show any deletion in the Miller-Dieker/isolated lissencephaly critical region on 17p13.3. The syndromes with lissencephaly are reviewed.     

3-M syndrome: a prenatal ultrasonographic diagnosis

The ultrasonographic imaging of a fetus affected by 3-M syndrome is described. This is a primordial dwarfism with low birthweight, short stature, facial dysmorphism and normal mental development. The biparietal diameter and head circumference were in accordance with the gestational age at 18 weeks. The femur and tibia lengths were on the fifth centile and the radius, ulna and humerus lengths were below the fifth centile. A second scan at 22 weeks showed slowing of growth of all long bones, with the femur, tibia, fibula, humerus, radius and ulna lengths further below the fifth centile. The pregnancy was terminated and postmortem examination confirmed the prenatal diagnosis. The differential diagnosis of skeletal dysplasias characterized by a slow growth of long bones is discussed and the conclusion reached that the detection of shortened long bones (below the fifth centile) is the only ultrasonographic finding of 3-M syndrome.     

Missed prenatal diagnosis of fragile-X syndrome

An account is given of a pregnancy in an obligatory carrier of the fragile-X syndrome, in whom examination of chorionic villus cells and fetal blood cells showed the presence of a male fetus who lacked the fragile-X chromosome. However, at 3 months of age he had 14 per cent of fragile-X cells in his blood. Reasons are suggested for this error in diagnosis. The empirical risk for an error of this sort is 3 per cent.     

The prenatal diagnosis of the Walker-Warburg syndrome

On the basis of physical features and autopsy findings, a child with congenital hydrocephalus, bilateral microphthalmia, myopathy, severe developmental retardation and multiple brain malformations was diagnosed to have the Walker-Warburg Syndrome (WWS). During a subsequent pregnancy in this family, a fetus at risk for this autosomal recessive condition was evaluated with serial ultrasound examinations. At 15 weeks of gestation an encephalocele was noted. Disproportionately slow growth of the head compared to the body was noted at 36 weeks. At birth, the diagnosis of WWS was confirmed in the child due to the presence of microcephaly, an encephalocele, a meningocele and bilateral microphthalmia. This is the first reported case of the early prenatal diagnosis of this recently categorized genetic condition, in which the major features are hydrocephalus, multiple central nervous system malformations, microphthalmia with ocular malformations, severe psychomotor retardation, congenital myopathy and a very limited life expectancy.     

Early prenatal diagnosis of the ICF syndrome

The ICF syndrome (immunodeficiency, (para)centromeric instability and facial abnormalities) is a rare autosomal recessive disorder with characteristic cytogenetic aberrations of chromosomes 1, 9 and 16 in lymphocytes. Previously, only one case has been diagnosed prenatally in the second trimester of pregnancy by fetal blood sampling. We report the first early prenatal exclusion of the ICF syndrome by chorionic villous sampling (CVS) and linkage analysis in a family with a previous affected child. The fetus was heterozygous for marker D20S850 closely linked to the ICF locus. The family was counselled of a probability of over 90% that the fetus would be unaffected. Postnatal chromosome analysis on peripheral blood was normal and thus confirmed the prenatal diagnosis.     

Early prenatal diagnosis of amniotic band syndrome

A case of amniotic band syndrome diagnosed at 16 weeks gestation is presented. The pregnancy was complicated by cervical incompetence. Restriction of fetal head movement was important in sonographic diagnosis.     

First-trimester prenatal diagnosis of Roberts syndrome.

We present a case of prenatal detection of premature centromere separation on chorionic villi sampled at 8 weeks' gestation from a woman at risk of recurrence of Roberts syndrome. The same cytogenetic characteristic was confirmed on amniocytes at 14 weeks when ultrasound examination showed morphological anomalies of the fetus. To our knowledge, this is the first report of early prenatal diagnosis of Roberts syndrome.     

Fetal facial profile in Pallister-Killian syndrome

Pallister-Killian syndrome (PKS) is a sporadic chromosomal anomaly, caused by a tissue-specific mosaic distribution of an additional isochromosome 12p. About 60 cases of prenatal diagnosis of PKS have been reported. Only 1 case of PKS is described on the basis of prenatal screening, presenting increased nuchal translucency. An abnormal fetal facial profile is described prenatally as sonographic evidence of PKS. We report a case of prenatal diagnosis in a fetus undergoing second-level scan due to positive triple screen with ultrasound features of PKS.     

Prenatal diagnosis of Pallister-Killian syndrome: resolution of cytogenetic ambiguity by use of fluorescent in situ hybridization.

We report a case of Pallister-Killian syndrome initially diagnosed prenatally as tetrasomy 21. A 33-year-old primiparous woman was noted at 24 weeks' gestation to have moderate polyhydramnios. Ultrasonography showed diminished fetal stomach filling, hydronephrosis, and prominence of the cisterna magna. Cytogenetic analysis of cultured amniocytes was initially interpreted as mosaic tetrasomy 21: 46,XX/47,XX,+i(21q). The patient was then referred to our centre for genetic counselling. At 34 weeks' gestation, a dysmorphic infant was delivered and died within 30 min. Physical features were consistent with the Pallister-Killian syndrome. Renal, gastrointestinal, and central nervous system anomalies were found at post-mortem examination. Analysis of peripheral lymphocytes revealed 5 per cent of cells with a marker chromosome, while 92 per cent of cultured fibroblasts had this same marker. Fluorescent in situ hybridization (FISH) using an alpha-satellite probe for chromosomes 13 and 21 failed to hybridize to the marker, while a chromosome 12 centromeric probe unequivocally identified it as an i(12p). Use of FISH can provide rapid, specific prenatal diagnosis of ambiguous marker chromosomes and improve prenatal counselling.     

Retrospective diagnosis and subsequent prenatal diagnosis of Nijmegen breakage syndrome

OBJECTIVE: We report on the retrospective diagnosis of Nijmegen breakage syndrome (NBS) confirmed by molecular genetic analysis and consecutive prenatal diagnosis in the same family. METHOD: Thirteen years after the death of their daughter due to fatal recurrent infections, a couple presented in our genetic counselling unit asking for the recurrence risk of their daughter's disease. Retrospective analysis of the medical record suggested that the girl might have suffered from NBS. Therefore, molecular genetic analysis for NBS was performed in the parents. RESULTS: After the diagnosis, NBS could be indirectly proven by molecular genetic heterozygosity testing of the parents, and a reliable prenatal diagnosis for a new pregnancy could be offered. In a following pregnancy, a massive hydrocephalus was diagnosed by ultrasound investigation. Amniocentesis was performed, and molecular analysis of the fetal DNA revealed homozygosity for the NBS1 mutation 657del5. CONCLUSION: The analysis of this family allows a further delineation of the prenatal NBS phenotype including hydrocephalus and dystopic kidneys that are helpful parameters to recognise NBS prenatally, also by ultrasound investigations in pregnancy. Additionally, we conclude that hydrocephalus might be more common in NBS patients than previously suggested.