Survival of fetuses with 45,X: an instructive case and an hypothesis

The high (greater than 95%) fetal loss rate of 45,X embryos and fetuses has led to the suggestion that fetal survival with this karyotype requires the presence of mosaicism. However, in many instances, even given a "mild Ullrich-Turner syndrome" phenotype, mosaicism is not detected. In a pregnancy studied for advanced maternal age, CVS cultured cells showed 65% 45,X and 35% 46,X,r(X). After termination, 2 fetal tissues showed 95% 45,X cells. It is suggested that infants with the 45,X karyotype likely had mosaicism for a structurally abnormal X or Y chromosome during embryogenesis, but the abnormal cell line disappeared prior to birth.

Molecular basis of hexosaminidase A deficiency and pseudodeficiency in the Berks County Pennsylvania Dutch

Following the birth of two infants with Tay-Sachs disease (TSD), a non-Jewish, Pennsylvania Dutch kindred was screened for TSD carriers using the biochemical assay. A high frequency of individuals who appeared to be TSD heterozygotes was detected (Kelly et al., 1975). Clinical and biochemical evidence suggested that the increased carrier frequency was due to at least two altered alleles for the hexosaminidase A alpha-subunit. We now report two mutant alleles in this Pennsylvania Dutch kindred, and one polymorphism. One allele, reported originally in a French TSD patient (Akli et al., 1991), is a GT-->AT transition at the donor splice-site of intron 9. The second, a C-->T transition at nucleotide 739 (Arg247Trp), has been shown by Triggs-Raine et al. (1992) to be a clinically benign "pseudodeficient" allele associated with reduced enzyme activity against artificial substrate. Finally, a polymorphism [G-->A (759)], which leaves valine at codon 253 unchanged, is described.

Progression of cardiac disease in Emery-Dreifuss muscular dystrophy

Emery-Dreifuss muscular dystrophy (EDMD) is a rare X-linked muscular dystrophy characterized by early contractures, progressive muscle weakness, and atrial arrhythmias. Recent reports suggest that there may be additional cardiac problems in affected males and that carrier females may also show ECG abnormalities. We restudied two large families with EDMD in order to determine the extent of these problems. We examined 10 affected males and interviewed 2 others. The 3 affected males less than 20 years old had no ECG changes. All affected men of 35 years or older had arrhythmias. One had more severe arrhythmias when asleep, indicating the usefulness of continuous 24-h ECG monitoring in the evaluation of males affected with EDMD. Two required pacemakers, 4 had already had a pacemaker placed, and 4 other affected men with pacemakers had died prior to this study. One affected man with a pacemaker developed ventricular bigeminy and another developed congestive heart failure. Thus of 10 affected males with pacemakers, 6 had additional cardiac symptoms and 4 have died. Males with EDMD may survive longer with a ventricular pacemaker, but this may increase the likelihood that they will develop cardiomyopathy and ventricular arrhythmias. Of 34 carrier females examined, 6 had arrhythmias typical of EDMD. Two required a pacemaker. The risk of arrhythmia increased with age. Results from one family should be extrapolated to another with caution, as there appears to be significant interfamilial variation. We suggest careful cardiologic follow-up of EDMD patients and regular cardiac evaluations for older carrier females.

Hypercoagulability in a patient with Marfan syndrome

A 39 year old man with Marfan syndrome presented with multiple pulmonary emboli and renal, hepatic, and splenic infarcts of unknown aetiology. The combination of thromboemboli and physical features initially suggested homocystinuria; however, laboratory examination showed no evidence for this disorder. Laboratory evaluation identified no coagulation abnormalities. This patient represents the unusual occurrence of hypercoagulability in a patient with Marfan syndrome.

Muscle enzymes and isoenzymes in Emery-Dreifuss muscular dystrophy

Emery-Dreifuss muscular dystrophy (EDMD) is a rare X-linked muscular dystrophy. Creatine kinase (CK) activity usually is increased in serum of affected males, but results for aldolase and lactate dehydrogenase (LD) in serum have been inconsistent, as have those for CK in carrier females. There have been few studies of CK-MB or LD isoenzyme-1 (LD-1) in EDMD. We measured CK, CK-MB, LD, LD-1, and aldolase activity in sera of 84 members of two large families with EDMD. DNA analysis had been carried out on all subjects. Although CK, LD, and aldolase activities were significantly increased in affected males, CK activity was the most consistently increased and was the least subject to artifactual increases. Mean CK-MB in serum was mildly increased, but LD-1 was within the normal reference interval, suggesting that CK-MB is increased in skeletal muscle in EDMD, as has been found in other forms of dystrophy. CK decreased with age in affected males. We saw no significant increases of muscle enzymes or isoenzymes in 33 EDMD carriers studied, of whom 19 were obligate carriers and 14 had been identified by DNA analysis.

Muscle enzymes and isoenzymes in Emery-Dreifuss muscular dystrophy

Emery-Dreifuss muscular dystrophy (EDMD) is a rare X-linked muscular dystrophy. Creatine kinase (CK) activity usually is increased in serum of affected males, but results for aldolase and lactate dehydrogenase (LD) in serum have been inconsistent, as have those for CK in carrier females. There have been few studies of CK-MB or LD isoenzyme-1 (LD-1) in EDMD. We measured CK, CK-MB, LD, LD-1, and aldolase activity in sera of 84 members of two large families with EDMD. DNA analysis had been carried out on all subjects. Although CK, LD, and aldolase activities were significantly increased in affected males, CK activity was the most consistently increased and was the least subject to artifactual increases. Mean CK-MB in serum was mildly increased, but LD-1 was within the normal reference interval, suggesting that CK-MB is increased in skeletal muscle in EDMD, as has been found in other forms of dystrophy. CK decreased with age in affected males. We saw no significant increases of muscle enzymes or isoenzymes in 33 EDMD carriers studied, of whom 19 were obligate carriers and 14 had been identified by DNA analysis.

Apparent Ruvalcaba syndrome with genitourinary abnormalities

The Ruvalcaba syndrome is a rare malformation syndrome characterized by skeletal dysplasia, facial anomalies, and mental retardation. We report on a 22-year-old woman with severe growth and mental retardation and numerous manifestations characteristic of the Ruvalcaba syndrome. In addition, she has several anomalies not previously described in the Ruvalcaba syndrome, including upslanting palpebral fissures, torus palatinus, hiatal hernia with gastroesophageal reflux, recurrent respiratory infections, pectus excavatum, equinovarous deformity, hypotonia, unilateral renal hypoplasia, an accessory ovary, and atretic fallopian tube. Review of published reports of Ruvalcaba syndrome confirms variability of the clinical and radiographic changes. Findings present in at least 50% of reported patients include mental retardation, short stature, pubertal delay, an abnormal nose (usually beaked) with hypoplastic nasal alae, microstomia with narrow maxilla, thin upper lip vermilion, broad hips, small hands, joint limitation, short fingers and toes, and vertebral abnormalities. Because 5 of the reported patients had renal abnormalities, a renal ultrasound or contrast study is indicated in the evaluation of these patients. Additional reports, particular from multiplex families, will be important to better characterize this syndrome.

Cytogenetic studies in couples with recurrent pregnancy loss

We reviewed the results of lymphocyte karyotypes from 232 couples who had had two or more pregnancy losses (spontaneous abortions or stillbirths). Despite the use of strict criteria to correct for possible bias of ascertainment, 8% of these couples (19 of 232) had a chromosome abnormality. Six of these abnormalities were low-percentage mosaicism for aneuploidy or a translocation. If these couples were excluded, 13 (6%) of the study couples had a chromosome abnormality. There was no significant difference in the incidence of chromosome abnormalities in those couples having two losses as compared with those having three or more losses. The study couples were referred from a wide range of sources, and most women had not had extensive gynecologic evaluation. These results confirm the importance of cytogenetic analysis of couples with recurrent pregnancy loss, and suggest that such studies be considered after two losses.

Isochromosome 12p mosaicism (Pallister mosaic aneuploidy or Pallister-Killian syndrome): report of 11 cases

We report on 11 cases of isochromosome 12p mosaicism (or Pallister mosaic aneuploidy syndrome) in which the isochromosome is usually absent in cultured lymphocytes but present in fibroblasts. The patients range in age from a 22-week-gestation fetus to a 45-year-old man. They have a distinct pattern of anomalies which enables one to make a diagnosis based on clinical manifestations alone. Craniofacial manifestations include "coarse" face with prominent forehead, sparsity of scalp hair, hypertelorism, epicanthal folds, flat bridge of nose, and highly arched palate. Affected newborn infants are profoundly hypotonic with sparsity of scalp hair especially bitemporally and a prominent forehead. Most have accessory nipples. Birthweight and growth parameters are usually normal; however, some newborn infants are unusually large. In infancy, the facial appearance becomes "coarse," hypotonia persists, and seizures may occur. As adults, growth may be normal, scalp hair is thicker and the mandible becomes prominent. Most have a generalized pigmentary dysplasia which may be evident with a Wood's lamp only. All cases have been sporadic and there is no consistent pattern of advanced parental age.

Pregnancy wastage associated with paracentric inversion of chromosome 13

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Secondary amenorrhoea and 47,XX,i(Xq) karyotype

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Prenatal diagnosis of Pena-Shokeir syndrome type 1

This report describes the sonographic diagnosis of the Pena-Shokeir syndrome type 1 during the second trimester of a pregnancy which was electively terminated. The mother had previously delivered a macerated, hydropic infant with multiple congenital anomalies. The diagnosis was based on the recurrence of hydramnios and nonimmune hydrops in a fetus with normal chromosomes, normal amniotic fluid alpha-fetoprotein, normal fetal echocardiography, and lack of evidence of a lysosomal storage disease. These observations suggest that serial sonography during the second trimester in pregnancies at risk may allow for the prenatal diagnosis of the Pena-Shokeir syndrome type 1. Without further experience, it would not be prudent to suggest to couples at risk that the prenatal diagnosis of a recurrence can be assured with a high degree of accuracy.

Autosomal recessive congenital cerebellar hypoplasia

We report three sibling pairs with congenital cerebellar hypoplasia. All six children presented in the first years of life with delays in motor and language development. All patients showed cerebellar and/or vermal dysfunction and, on formal psychometric testing, cognitive abilities ranged from normal to moderately retarded. Abnormalities on CT scan ranged from prominent valleculla to an enlarged cisterna magna with hypoplasia of the cerebellar hemispheres and vermis. The pedigrees are consistent with autosomal recessive inheritance.

Hereditary motor-sensory neuropathy (HMSN): possible X-linked dominant inheritance

The inheritance of the hereditary motor and sensory neuropathies (HMSN) is usually autosomal dominant. We studied a kinship with a pattern of X-linked dominant inheritance. The phenotype was similar to HMSN of the "intermediate" type. Men were more severely affected than women, and hypertrophic nerves were not found. Nerve conduction was very slow in men, but it was mildly slow or normal in women. No male-to-male transmission was found in six generations.

De novo 21q interstitial deletion in a retarded boy with ulno-fibular dysostosis

A 9-year-old boy was referred for evaluation of multiple anomalies and mental retardation. Skeletal abnormalities had been noted at birth: joint contractures, right acetabular "dysplasia," ulno-fibular dysostosis, and bilateral talipes equinovarus with calcaneocuboid fusion. Additional findings at 9 years included short stature, unusual facial appearance, camptodactyly of several digits, undescended testes, and syndactyly of toes 4 and 5. On psychological testing he was found to be moderately retarded. Cytogenetic analysis of chromosome bands using Q, GTG, R, and C banding showed an interstitial deletion of 21q; karyotype designation: 46,XY, del (21)(pter----q11.2::q22.1----qter). Parental chromosomes were normal. Manifestations in this boy, including the joint contractures, are similar to those described in the monosomy 21 syndrome. Ulno-fibular dysostosis has not been reported previously with abnormalities of chromosome 21. To our knowledge, this is the second patient reported with an interstitial deletion of chromosome 21, and the patients are phenotypically dissimilar.

Teratogenicity of anticonvulsant drugs. II: A prospective study

To 468 women with epilepsy enrolled in the study, 171 children were born and evaluated prospectively. The mothers in this group were characterized by low socioeconomic status, high frequency of tonic-clonic generalized seizures, and use of combinations of anticonvulsants. Approximately 30% of infants exposed to diphenylhydantoin in utero had minor craniofacial and digital changes. The infants did not show an increased rate of growth retardation, mental retardation, or major malformations. It is suggested that the nature of the association of birth defects and maternal epilepsy is complex and that the teratogenicity of anticonvulsant drugs plays only a minor role in this association. The sample size necessary to demonstrate a two- to threefold increase in malformations is beyond the capability of a single center.

Teratogenicity of anticonvulsant drugs. IV: The association of clefting and epilepsy

Cleft lip with or without cleft palate (CL/P) is the most common congenital malformation reported among infants of epileptic mothers. This study sought to examine the relative roles of anticonvulsant teratogenicity and other factors responsible for this association. Among 175 families with a proband with isolated CL/P, there were 13 parents with epilepsy and a high frequency of other family members with CL/P and epilepsy. Evaluation of the 13 cases suggested that teratogenicity of anticonvulsant drugs was not the primary factor responsible for the observed association of maternal epilepsy and clefting. Among 140 families with a proband with clefting other than CL/P, there were no instances of parental epilepsy observed.

Teratogenicity of anticonvulsant drugs. III: Radiographic hand analysis of children exposed in utero to diphenylhydantoin

As part of a prospective study of the teratogenicity of anticonvulsant drugs, hand radiographs were obtained on 51 children born to epileptic mothers. The phalanges and metacarpals were measured and a diagnosis of distal digital hypoplasia (DDH) was made if the distal phalangeal to other digital bone ratio was more than 2 SD below the mean for age in at least two of the digits. By these criteria, roughly 30% of infants exposed to diphenylhydantoin in utero demonstrate DDH; this was in close agreement with the clinical diagnosis of DDH. The data suggest that there is no familial tendency to the expression of this teratogenicity, there is no sex influence, there is no difference between exposure to diphenylhydantoin alone and diphenylhydantoin in combination with other anticonvulsants, and that the digital changes occur most often in the absence of other sequelae of in utero exposure to diphenylhydantoin.

Preaxial polydactyly type 4: variability in a large kindred

A five generation family with type 4 preaxial polydactyly is reported. The 21 affected individuals demonstrated variability in expression without apparent sex influence and penetrance which was complete. The deformities were more severe in the feet than the hands. Anteroposterior flatness of the thumbs was the only manifestation of the trait in the hands of several affected family members.

Distal 15q trisomy: phenotypic comparison of nine cases in an extended family

Nine related individuals have been identified as being trisomic for the distal part of the long arm of chromosome 15 (15q23 to 15qter). The physical characteristics, especially the facial features, of these nine cases are similar and distinctive. These include: facial asymmetry, down-slanting palpebral fissures, ptosis, prominent nose, long philtrum, down-turned mouth, midline crease in the lower lip, puffy cheeks, and micrognathia. By comparing related individuals with the same translocation, the variability due to different breakpoints can be eliminated. Clinical similarities between unrelated individuals with similar duplicated 15q material, but differing second chromosomes, suggest that the phenotype is due to the extra distal 15q chromosomal material. We conclude that distal 15q trisomy produces a clinically recognizable syndrome.

X;Y translocation in a female with streak gonads, H-Y- phenotype, and some features of Turner's syndrome

In women X;Y translocations usually arise as Xp-Yq exchanges. We describe a 17-year-old female with streak gonads, some minor features of Turner's syndrome, and an X;Y translocation involving an exchange between Xq and Yq. Histological examination of the gonads revealed a fibrous stroma with prominent hilar cells. Cultured fibroblasts and peripheral lymphocytes were typed H-Y-. Examination of a buccal smear revealed a single intranuclear structure with the appearance of both a Barr body and a fluorescent Y body. This finding was consistent with the results of BrdU studies showing that the translocation X chromosome had been inactivated in all cells analyzed.

Trisomy 4p in four relatives: variability and lack of distinctive features in phenotypic expression

We report two brothers and two second cousins with 4p trisomy secondary to a familial translocation t(4;7) (p12;q36). A comparison of their physical features demonstrates the variability of clinical manifestations associated with this chromosome abnormality. While previous authors have emphasized the distinctiveness of the 4p trisomy syndrome, the variability seen in the affected relatives in this family suggests that trisomy 4p is one of the less distinctive chromosomal syndromes. Further comparison of our patients with the previously reported cases of 4p trisomy and with two cases whose chromosomal breakpoints were similar confirms this variability. Studies of phenotype/karyotype correlations in affected relatives provides the best opportunity to determine the phenotypic consequences of a specific (that is, identical) translocation. Studies of unrelated persons are complicated by the effects of different breakpoints and of possible partial deletions.