Cutaneous clues for diagnosing X-chromosomal disorders.

In a multidisciplinary outpatient clinic for hereditary skin diseases and/or syndromes involving the skin, 7% (30 of 409) of patients were found to have an abnormality involving the X chromosome, a mutation in a gene located on the X chromosome or a clinical diagnosis of an X-linked monogenetic condition. The collaboration of a dermatologist and a clinical geneticist proves to be very valuable in recognizing and diagnosing these conditions. By combining their specific expertize in counselling an individual patient, X-linked diagnoses were recognized and could be confirmed by molecular and/or cytogenetic studies in 24 of 30 cases. Mosaicism plays an important role in many X-linked hereditary skin disorders. From our experience, we extracted clinical clues for specialists working in the field of genetics and/or dermatology for considering X-linked disorders involving the skin.

Hyperechogenic fetal bowel: counseling difficulties.

The detection of echodense fetal bowel on ultrasound examination in the second trimester of pregnancy justifies invasive procedures such as amniocentesis to detect an underlying cause. We present a case in which initial tests identified only one mutation in the cystic fibrosis transmembrane regulator (CFTR)-gene of the fetus, the family history being negative for CF. Strongly reduced intestinal enzyme activities suggested intestinal obstruction and further increased the estimated risk for CF. After the 24th gestational week, a second mutation was found, confirming cystic fibrosis in this child. Problems in counseling in this particular case are discussed.

bcr-abl mRNA lacking abl exon a2 detected by polymerase chain reaction in a chronic myelogeneous leukemia patient.

Using the polymerase chain reaction and Southern blot analysis the expression was detected of a bcr-abl mRNA lacking abl exon a2. This was due to a corresponding unusual localization of the breakpoint in the c-abl gene and was seen in a patient with Philadelphia (Ph) chromosome positive chronic myelogeneous leukemia in chronic phase. This type of mRNA has been described only once before in two Ph-positive acute lymphoblastic leukemia patients, by Soekarman et al. (1). The abl exon a2 sequences, which are missing in the three reported patients, code for a part of the SH3 region of the abl protein, which is supposed to be involved in negative regulation of the kinase domain. The clinical significance of this finding is discussed.

A novel variant of the bcr-abl fusion product in Philadelphia chromosome-positive acute lymphoblastic leukemia.

Two patients with Philadelphia chromosome-positive acute lymphoblastic leukemia showed novel variants of the chimeric bcr-abl mRNA. The bcr-abl breakpoint region on cDNA derived from the chimeric mRNA was amplified using the polymerase chain reaction (PCR). Sequence analysis of the breakpoint-containing fragment showed that in both patients exon a2 of the abl gene was deleted, giving rise to an in-frame joining at the mRNA level of 5' bcr sequences to the abl exon a3. These findings were confirmed by Southern blot analysis and cloning of chromosomal DNA. Protein studies showed a bcr-abl protein with heightened tyrosine kinase activity in blast cells of both patients: one of the P190 type, the other of the P210 type. The significance of these findings and the role of this new type of translocation in the disregulation of the abl gene are discussed.

Dek-can rearrangement in translocation (6;9)(p23;q34).

The translocation (6;9)(p23;q34) is mainly found in specific subtypes of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). The diagnosis of this translocation is not easy since the cytogenetic change is quite subtle. The two genes involved in this translocation were recently isolated and diagnosis at the DNA-level became an additional option. Both the dek gene on chromosome 6 and the can gene on chromosome 9 contain one specific intron where breakpoints of t(6;9) patients were found to cluster. The translocation results in a consistent chimeric dek-can mRNA which is generated from the 6p- derivative. Five centers participated in a study to estimate the incidence of t(6;9) in leukemic patients using conventional Southern blot analysis. Patients (n = 320) with either acute undifferentiated leukemia (AUL), AML, MDS or acute lymphoblastic leukemia (ALL) were screened for rearrangement of the genes involved in this translocation. Four of these 320 patients showed rearrangement of the can gene on chromosome 9, of which one also had a rearranged dek gene on chromosome 6. A further 20 patients were studied with karyotypic aberrations in which either the short arm of chromosome 6 or the long arm of chromosome 9 were specifically involved. Both conventional Southern blot analysis and contour-clamped homogeneous electric field (CHEF) analysis failed to show dek-can rearrangement in any of these patients. The results of our study indicate that the incidence of the t(6;9) is a low as reported based on cytogenetic data and that rearrangement of the dek and can genes is mainly restricted to this specific translocation.

Corpus callosum agenesis in Coffin-Lowry syndrome.

We describe a boy with the syndrome of Coffin-Lowry whose CT-scan showed corpus callosum agenesis. Follow-up data are given and diagnostic considerations are discussed. A review is given of the CNS-malformations so far reported in patients with the syndrome of Coffin-Lowry.

Extreme growth failure and kyphoscoliosis as complications of the distal trisomy 10q syndrome.

The patient was diagnosed in infancy. Clinical findings and results of re-evaluation 13 years after diagnosis are presented.

On the nosology of the craniodigital syndromes: report of a family and review of the literature.

During a systematic survey for genetic causes of mental retardation in schools for adolescents with learning problems we had the occasion to examine a 16-year-old moderately mentally retarded boy with facial dysmorphism, short stature, relative microcephaly, complete cutaneous syndactyly of fingers III/IV and of toes II/III. Partial clinical manifestations (low to subnormal intelligence and syndactyly) were present in his mother and sister. We discuss the nosology and differential diagnosis of the craniodigital syndromes.

Increased head circumference and facial cleft as presenting signs of the nevoid basal-cell carcinoma syndrome.

We report a child with nevoid basal-cell carcinoma syndrome (NBCCS) who showed an enlarged head circumference and cleft lip/cleft palate as sole signs of this syndrome at birth. Careful follow up and re-evaluation of this patient enabled us to diagnose the syndrome. Moreover, inspection of her father and sister indicated that they were also affected. An updated review of reported cases indicates that facial cleft occurs in approximately 5% of NBCCS patients. Various aspects of the disease and general measures for its monitoring and treatment are briefly discussed.

Pfeiffer acrocephalosyndactyly syndrome in mother and son with cloverleaf skull anomaly in the child.

A boy is reported with the cloverleaf skull anomaly as part of the Pfeiffer syndrome. So far, this combination has only been observed in sporadic cases. However, the mother of this patient had also the syndrome of Pfeiffer, indicating that the cloverleaf skull abnormality may occur in familial cases. Development of the child after birth and therapeutic approaches are reported.

Marden-Walker phenotype: a diagnostic dilemma.

Two cases are presented with a phenotype mostly resembling the condition named Marden-Walker syndrome. Main features of this condition are blepharophimosis, micrognatia, congenital joint contractures, mental retardation, growth retardation and decreased muscular mass. Follow-up data of patients with this condition are scarce and most patients reported so far were infants or young children. We report two patients meeting many of the criteria proposed for diagnosing this particular phenotype. One case was diagnosed in adolescence and the other as an adult. Initially described as a syndrome, this condition is more likely to be a phenotypic expression of various heterogeneous diseases.

Macrocephaly and mental retardation. The unique association with short stature, spastic paraplegia and CNS malformations.

During a systematic clinical genetic survey of the institutionalized moderately to severely mentally retarded we had the occasion to examine two nonrelated adult patients who presented a similar MCA/MR syndrome: 1) macrocephaly (OFC > 60 cm) with high and broad forehead and contrasting relative midfacial hypoplasia; 2) short stature with small and broad hands and feet; 3) neurological symptoms of a variable degree of spastic paraplegia and severe CNS malformations on CT-scan i.e. internal hydrocephalus and Dandy-Walker variant malformation.

Spinal anesthesia for a parturient with the triad of Currarino.

The triad of Currarino, also known as Currarino syndrome or complex, is a rare hereditary syndrome involving a bony sacral defect, an anorectal malformation and a presacral mass. Thus far, only 250 cases have been reported, but milder cases may not be recognized, and many cases may not be published. In addition to disorders of the gastrointestinal and urogenital tracts, sensory and motor deficits may be present. Currently, there are no reports of women with the triad of Currarino undergoing cesarean delivery with the use of neuraxial anesthesia. Neuraxial anesthesia in patients with congenital malformations of the spine may be complicated or contraindicated, depending on the level and severity of the anatomic abnormality. We present the case of a pregnant woman at 36 weeks of gestation who underwent uncomplicated neuraxial anesthesia for cesarean delivery. When neuraxial anesthesia is contemplated in such patients, they should first receive careful neurologic and radiologic evaluation.

Skin changes in oculo-dento-digital dysplasia are correlated with C-terminal truncations of connexin 43.

Oculo-dento-digital dysplasia (ODDD, OMIM no.164210) is a pleiotropic disorder caused by mutations in the GJA1 gene that codes for the gap junction protein connexin 43. While the gene is highly expressed in skin, ODDD is usually not associated with skin symptoms. We recently described a family with ODDD and palmoplantar keratoderma. Interestingly, mutation carriers had a novel dinucleotide deletion in the GJA1 gene that resulted in truncation of part of the C-terminus. We speculated, that truncation of the C-terminus may be uniquely associated with skin disease in ODDD. Here, we describe a patient with ODDD and palmar hyperkeratosis caused by a novel dinucleotide deletion that truncates most of the connexin 43 C-terminus. Thus, our findings support the notion that such mutations are associated with the occurrence of skin symptoms in ODDD and provide the first evidence for the existence of a genotype-phenotype correlation.

Novel EBP gene mutations in Conradi-Hünermann-Happle syndrome.

BACKGROUND: Conradi-Hünermann-Happle syndrome [X-linked dominant chondrodysplasia punctata type 2 (CDPX2); MIM no. 302960] is an X-linked dominant disorder of cholesterol metabolism that causes a wide spectrum of skeletal abnormalities and linear ichthyosiform skin lesions. Mosaicism is probably responsible for the variability of the phenotype. OBJECTIVES: To describe new mutations in patients with variable manifestations of the disease. METHODS: We studied three patients with CDPX2. We performed mutation analysis of the EBP (formerly known as CDPX2) gene and gas chromatography-mass spectroscopy on serum of two patients. RESULTS: We found two novel (3G-->T and 419-422delTTCT) and one known mutation in the EBP gene. We demonstrated the presence of increased levels of dehydrocholesterol and 8(9)-cholestenol in the two patients with new mutations, confirming the diagnosis of CDPX2 and strongly suggesting that the mutations are indeed pathogenic. One patient had a very mild phenotype, presenting with linear alopecia and a mild symmetrical epiphyseal dysplasia. X-inactivation studies in peripheral blood of all patients showed skewing in only the most severely affected patient. CONCLUSIONS: The strong phenotypic variability in our patients suggests that there is no clear genotype-phenotype correlation.

Epidural local anesthetics: a novel treatment for fetal growth retardation?

BACKGROUND: Chronically compromised uterine perfusion may lead to placental insufficiency and subsequent intrauterine growth restriction (IUGR). Various therapeutic approaches (e.g. vasodilators, low-dose aspirin, intravenous glucose infusion, and hemodilution) are often of limited efficacy. Local anesthetics have been shown to improve placental blood flow in pre-eclamptic women. We hypothesized that epidural administration of local anesthetics might improve outcome in IUGR independent of the underlying cause. In preparation for a clinical trial to test this hypothesis, we performed a pilot study in 10 patients. METHODS: After approval of the study protocol, 10 pregnant women presenting with oligohydramnios and IUGR were included in the study. In addition to our standard protocol (magnesium, glucose, betamethasone), each patient received an epidural catheter (T10/T12) with continuous infusion of bupivacaine 0.175% at a rate of 5 ml/h. Uteroplacental circulation was monitored by Doppler sonography and the amount of amniotic fluid was estimated daily. RESULTS: Epidural insertion and infusion was performed without complications. Four patients continued to deteriorate rapidly, amniotic fluid volume did not change and uterine artery pulsatility index (PI) tended to increase. In the remaining 6 patients the clinical status stabilized, amniotic fluid volume tended to increase and uterine artery PI tended to decrease during treatment. This improvement was associated with a prolonged interval to cesarean section and increased infant birth weight. CONCLUSION: Our data suggest that, even if the underlying cause of IUGR is not pre-eclampsia, epidural local anesthetic administration might improve placental blood flow and be beneficial in a subgroup of patients. A clinical trial to test this hypothesis appears warranted.

Sonographic genital ambiguity in a fetus due to a mosaic 45,X/46,X,idic(Y)(qter-p11.32::p11.32-qter) karyotype.

Nowadays, improved ultrasound techniques enable the detection of more subtle congenital abnormalities at an earlier stage of fetal development. Current cytogenetic techniques can characterize a chromosomal abnormality in greater detail. These advancements in both diagnostic possibilities have helped to answer many questions but have also created new issues and dilemmas in counselling. This is illustrated by this case report of a 35-year-old woman, who presented at the end of the second trimester of her first pregnancy. Sonographic examination indicated an abnormal external genital in a male fetus. A differential diagnosis of hypospadia was made. During follow-up, an amniocentesis was performed, and this showed a 45,X/46,X,idic(Y)(qter-p11.32::p11.32-qter) karyotype as the cause of the sonographic findings. Cytogenetic characterization of the isodicentric Y chromosome and pre- and post-natal findings in the child are reported. Cases with a similar karyotype reported in the literature are reviewed.

Hypohidrotic ectodermal dysplasia, central nervous system malformation, and distinct facial features: confirmation of a distinct entity?

Internal hydrocephalus with partial hypoplasia of the cerebellum was observed in a severely mentally retarded boy who showed signs of ectodermal dysplasia. Diagnostic considerations are discussed. Reports of the triad mental retardation-CNS malformation-ectodermal dysplasia are rare. In 1989 we reported a case with these signs that shows a striking facial similarity to the case presented here.

The KBG syndrome: follow-up data on three affected brothers.

In this report we present follow-up data on a family in which several members were found to have short stature, craniofacial anomalies and dento-skeletal abnormalities (KBG-syndrome). As adults, the three affected brothers of the original report are moderately to severely mentally retarded. Their phenotype with a distinct craniofacial appearance did not change much from that seen during childhood and adolescence. Adult height is far below the third centile, with arm spans exceeding stature by at least 9 cm.