Lilian Maria José Albano

Microduplication of the ICR2 Domain at Chromosome 11p15 and Familial Silver-Russell Syndrome

Silver–Russell syndrome (SRS) is characterized by severe intrauterine and postnatal growth retardation in association with a typical small triangular face and other variable features. Genetic and epigenetic disturbances are detected in about 50% of the patients. Most frequently, SRS is caused by altered gene expression on chromosome 11p15 due to hypomethylation of the telomeric imprinting center (ICR1) that is present in at least 40% of the patients. Maternally inherited duplications encompassing ICR1 and ICR2 domains at 11p15 were found in a few patients, and a microduplication restricted to ICR2 was described in a single SRS child. We report on a microduplication of the ICR2 domain encompassing the KCNQ1, KCNQ1OT1, and CDKN1C genes in a three‐generation family: there were four instances of paternal transmissions of the microduplication from a single male uniformly resulting in normal offspring, and five maternal transmissions, via two clinically normal sisters, with all the children exhibiting SRS. This report provides confirmatory evidence that a microduplication restricted to the ICR2 domain results in SRS when maternally transmitted.

Further evidence of genetic heterogeneity in Costello syndrome: involvement of the KRAS gene

AbstractCostello syndrome is an autosomal dominant disorder comprising growth deficiency, mental retardation, curly hair, coarse facial features, nasal papillomata, low-set ears with large lobes, cardiac anomalies, redundant skin in palms and soles with prominent creases, dark skin, and propensity to certain solid tumors. HRAS mutations have been implicated in approximately 85% of the affected cases. The clinical overlap among Costello, Noonan, and cardiofaciocutaneous syndromes is now better understood given their common molecular background, such that all these syndromes constitute a class of disorders caused by deregulated RAS-MAPK signaling. We report on a novel KRAS gene mutation in a patient presenting the clinical features typical of Costello syndrome and the additional findings seen in Noonan syndrome. This description emphasizes that a subset of patients with Costello syndrome could harbor mutations in other genes involved in the RAS-MAPK signaling.

Hematological findings in Noonan syndrome

OBJECTIVE Noonan syndrome is a multiple congenital anomaly syndrome, and bleeding diathesis is considered part of the clinical findings. The purpose of this study was to determine the frequency of hemostatic abnormalities in a group of Noonan syndrome patients. METHOD We studied 30 patients with clinical diagnosis of Noonan syndrome regarding their hemostatic status consisting of bleeding time, prothrombin time, activated partial thromboplastin time and thrombin time tests, a platelet count, and a quantitative determination of factor XI. RESULTS An abnormal laboratory result was observed in 9 patients (30%). Although coagulation-factor deficiencies, especially factor XI deficiency, were the most common hematological findings, we also observed abnormalities of platelet count and function in our screening. CONCLUSIONS Hemostatic abnormalities are found with some frequency in Noonan syndrome patients (30% in our sample). Therefore, we emphasize the importance of a more extensive hematological investigation in these patients, especially prior to an invasive procedure, which is required with some frequency in this disorder.

A Known SOST Gene Mutation Causes Sclerosteosis in a Familial and an Isolated Case from Brazilian Origin

Sclerosteosis is a severe, rare, autosomal recessive bone condition that is characterized by a progressive craniotubular hyperostosis. The main features are a significant sclerosis of the long bones, ribs, pelvis, and skull, leading to facial distortion and entrapment of cranial nerves. Clinical features include a tall stature, nail dysplasia, cutaneous syndactyly of some fingers, and raised intracranial pressure. The sclerosteosis gene has been mapped to chromosome 17q12-21 and is currently known as the SOST gene encoding the sclerostin protein. Here, we report on one familial and one isolated case of Brazilian origin with the clinical and molecular diagnosis of sclerosteosis. The radiological and clinical features are described, and the diagnosis of sclerosteosis was confirmed in both cases by mutation analysis of the SOST gene showing a homozygous nonsense mutation (Trp124X) in the two patients. We reported this mutation previously in other sclerosteosis patients from a consanguineous Brazilian family. Interestingly, all three families were from the same state in Brazil, but they denied familial relationship. These patients confirm the clinical picture as found in other cases with a loss of function mutation in the SOST gene.

Cockayne syndrome type A: novel mutations in eight typical patients

AbstractCockayne syndrome is a rare autosomal recessive neurodegenerative disorder. It is considered to be a heterogeneous condition based on complementation in cell fusion studies, with two major forms, namely CS-A and CS-B. CKN1 is the gene responsible for CS-A, whose mutations disrupt the transcription-coupled repair system of the actively transcribed DNA. Mutation analysis of the CKN1 gene in eight typical CS-A Brazilian patients from six families showed a gene alteration in all of them. We found a total of five novel mutations that were absent from healthy control subjects. Six affected subjects were simple homozygotes and two affected siblings were each compound heterozygotes. While the findings extend the range of mutations in CS-A, there is no obvious genotype-phenotype correlation across the mutational spectrum.

Clinical and laboratorial study of 19 cases of mucopolysaccharidoses

UNLABELLED The mucopolysaccharidoses (MPS) are a heterogeneous group of inborn errors of lysosomal glycosaminoglycan (GAG) metabolism. The importance of this group of disorders among the inborn errors of metabolism led us to report 19 cases. METHOD We performed clinical, radiological, and biochemical evaluations of the suspected patients, which allowed us to establish a definite diagnosis in 19 cases. RESULTS Not all patients showed increased GAG levels in urine; enzyme assays should be performed in all cases with strong clinical suspicion. The diagnosis was made on average at the age of 48 months, and the 19 MPS cases, after a full clinical, radiological, and biochemical study, were classified as follows: Hurler - MPS I (1 case); Hunter - MPS II (2 cases); Sanfilippo - MPS III (2 cases); Morquio - MPS IV (4 cases); Maroteaux-Lamy - MPS VI (9 cases); and Sly - MPS VII (1 case). DISCUSSION The high relative frequency of Maroteaux-Lamy disease contrasts with most reports in the literature and could express a population variability.

Cardiac findings in 31 patients with Noonan's syndrome

OBJECTIVE To evaluate cardiac findings in 31 Noonan syndrome patients. METHODS Thirty-one (18 males and 13 females)patients from 26 families affected with Noonans syndrome were evaluated from the cardiac point of view with electrocardiography and Doppler echocardiography. RESULTS Twenty patients had some type of cardiac abnormality. The most frequent was pulmonary valve stenosis followed by hypertrophic myocardiopathy, commonly associated with valve defects. Upper deviation of the QRS axis was observed in 80% of these patients. CONCLUSION In view of the high frequency and diversity of cardiac abnormalities present in Noonan syndrome, cardiac evaluation with electrocardiography and echocardiography should be performed in all patients diagnostically suspected of having this disease.

Craniosynostosis in pycnodysostosis: Broadening the spectrum of the cranial flat bone abnormalities†

Pycnodysostosis is a rare autosomal recessive skeletal dysplasia caused by the absence of active cathepsin K, which is a lysosomal cysteine protease that plays a role in degrading the organic matrix of bones, acting in bone resorption and bone remodeling. The disease is primarily characterized by osteosclerosis, bone fragility, short stature, acro‐osteolysis, and delayed closure of the cranial sutures. A differing feature, cranial synostosis, has occasionally been described in this disorder. We reviewed six unrelated patients with pycnodysostosis (mean age of 10 years and 4 months) in order to evaluate the presence of craniosynostosis. In addition to the typical findings of the condition, they all presented premature fusion of the coronal suture. Although none of them showed signs of cranial hypertension, one patient had had the craniosynostosis surgically corrected previously. These data suggest that the cranial sutures in pycnodysostosis can display contradictory features: wide cranial sutures, which are commonly described, and craniosynostosis. The clinical impact of this latter finding still remains to be elucidated. Further studies are necessary to address more precisely the role of cathepsin K in suture patency.

Friedreich's ataxia: cardiac evaluation of 25 patients with clinical diagnosis and literature review.

OBJECTIVE Cardiac evaluation (clinical, electrocardiographic and echocardiographic) of 25 Brazilian patients with clinical diagnosis of Friedreichs ataxia (FA) related to the frequency and the size of GAA repeats (unstable expansion of trinucleotide repeats that results in the disease). METHODS Clinical and cardiac study including electrocardiogram and echocardiogram of all patients and molecular analysis to detect the frequency and the size of GAA expansion, by polymerase chain reaction analysis. RESULTS Homozygous GAA expansion was detected in 17 patients (68%) - all typical cases. In 8 (32%) cases (6 atypical and 2 typical), no GAA expansion was observed, therefore it was not considered Friedreichs ataxia. All patients with GAA expansion (100%) had electrocardiographic abnormalities, and only 25% of the cases without GAA expansion had some abnormality on this exam. However, only 6% of all patients revealed some signals/symptoms suggestive of cardiac involvement. CONCLUSION A molecular analysis is essential to confirm the diagnosis of Friedreichs ataxia; however, an adequate cardiac evaluation, including an electrocardiogram, was extremely useful to better screening the patients which should perform these molecular analysis.

AEC Syndrome and CHAND Syndrome: Further Evidence of Clinical Overlapping in the Ectodermal Dysplasias

Abstract: Among the ectodermal dysplasias, there are several examples of overlapping phenotypes in disorders that are considered distinct. We report a 5‐year‐old boy born to nonconsanguineous parents and presenting with ectodermal dysplasia, ankyloblepharon filiforme adnatum, and bilateral choanal atresia consistent with the diagnosis of AEC syndrome. We compare the findings in our patient with the previous reported cases and discuss the overlapping phenotype of this disorder with CHAND syndrome.