Two novel COL1A1 mutations in patients with osteogenesis imperfecta (OI) affect the stability of the collagen type I triple-helix

Osteogenesis imperfecta (OI) is a bone dysplasia caused by mutations in the COL1A1 and COL1A2 genes. Although the condition has been intensely studied for over 25 years and recently over 800 novel mutations have been published, the relation between the location of mutations and clinical manifestation is poorly understood. Here we report missense mutations in COL1A1 of several OI patients. Two novel mutations were found in the D1 period. One caused a substitution of glycine 200 by valine at the N-terminus of D1 in OI type I/IV, lowering collagen stability by 50% at 34 degrees C. The other one was a substitution of valine 349 by phenylalanine at the C-terminus of D1 in OI type I, lowering collagen stability at 37.5 degrees C. Two other mutations, reported before, changed amino residues in D4. One was a lethal substitution changing glycine 866 to serine in genetically identical twins with OI type II. That mutated amino acid was near the border of D3 and D4. The second mutation changed glycine 1040 to serine located at the border of D4 and D0.4, in a proband manifesting OI type III, and lowered collagen stability at 39 degrees C (2 degrees C lower than normal). Our results confirm the hypothesis on a critical role of the D1 and D4 regions in stabilization of the collagen triple-helix. The defect in D1 seemed to produce a milder clinical type of OI, whereas the defect in the C-terminal end of collagen type caused the more severe or lethal types of OI.

[Characterization of marker chromosomes using molecular cytogenetic methods in patients with mental retardation and congenital malformations]

INTRODUCTION

Until recently, great variety of marker chromosomes and difficulties with their identification have presented a problem for cytogenetic and clinical interpretation of the karyotype. At present, molecular cytogenetic methods of chromosome analysis enable precise characterization of such abnormalities providing knowledge necessary for estimation of their genetic risk.

AIM

The aim of the study was molecular cytogenetic characterization of marker chromosomes recognized in three patients, an analysis of clinical features in relation to the abnormality and estimation of genetic risk of identified markers.

PATIENTS AND METHODS

Karyotypes of three phenotypically abnormal patients were estimated in lymphocytes from peripheral blood by G banding analysis. Marker chromosomes were identified by fluorescence in situ hybridization (FISH), multiplex FISH, multicolor band and high resolution comparative genomic hybridization methods.

RESULTS

Marker chromosomes were identified as inv dup(22)(pter->q11.2::q11.2->pter), der(8)(:p22->q11.2:), der(2l)(:pter->q21.3:) and der(19)(:p11->q13.1). All of them contained euchromatic sequences. First marker, an inverted duplication of chromosome 22q11.2 corresponding to tetrasomy of this chromosome region was recognized in a child with partial cat eye syndrome. Two further markers derived from chromosomes 8 and 21 were found in a child with mosaic karyotype and clinical features of trisomy 8p. In the third case additional chromosome material was derived from chromosome 19 and it was found in a patient with mild mental retardation and clinical features of ovary dysgenesis. Genetic risk of identified marker chromosomes except for mar(19) was estimated as high.

CONCLUSIONS

Our results provide further evidence for diagnostic value of molecular cytogenetic methods. They also confirmed the general opinion of the high risk of phenotypic abnormalities in the carriers of marker chromosomes containing euchromatic sequences.

[Cytogenetic-molecular analysis of balanced chromosomal rearrangements in nine patients with intellectual disability, dysmorphic features and congenital abnormalities]

INTRODUCTION

In about 6% of individuals with intellectual disability, dysmorphic features and congenital anomalies, an abnormal, apparently balanced karyotype is found. These abnormalities may result from abnormal expression of genes at the breakpoints, presence of a submicroscopic deletion, or other unbalanced chromosome aberrations. In such cases, the detailed analysis of breakpoints of balanced chromosome rearrangements may help with identification of genes responsible for patient's clinical features.

AIM OF WORK

Was the explanation of causes of abnormal phenotype in the carriers with abnormal but balanced karyotype.

MATERIAL AND METHODS

Cytogenetic-molecular analysis performed in nine patients with mental retardation, dysmorphic features and congenital anomalies. Studies with subtelomeric probes, high resolution comparative genomic hybridization (HR-CGH) and fluorescence in situ hybridization (FISH) with region-specific BAC clones were performed.

RESULTS

Seventeen chromosome breakpoint regions were narrowed to 200-400 kb. In one case, an 0.5-Mb submicroscopic deletion associated with more complex rearrangement has been found. Mapping of the breakpoints and information obtained from the UCSC Human Genome Browser data base enabled identification of 46 genes in these regions. Twelve genes, that may have been disrupted as a result of the patients' chromosomal rearrangement, were found. At four different breakpoints the identified genes (NRCAM, NPTX1, NMT1, MAPT, HDAC5 and MEF2C) may be due to a position effect.

CONCLUSIONS

The results confirm earlier suggestions concerning reasons of abnormal phenotype in the patients with balanced chromosome rearrangements and present the value of detailed analysis of the genome in such cases.

Molecular analysis of a constitutional complex genome rearrangement with 11 breakpoints involving chromosomes 3, 11, 12, and 21 and a ∼0.5-Mb submicroscopic deletion in a patient with mild mental retardation

Complex chromosome rearrangements (CCRs) are extremely rare but often associated with mental retardation, congenital anomalies, or recurrent spontaneous abortions. We report a de novo apparently balanced CCR involving chromosomes 3 and 12 and a two-way translocation between chromosomes 11 and 21 in a woman with mild intellectual disability, obesity, coarse facies, and apparent synophrys without other distinctive dysmorphia or congenital anomalies. Molecular analysis of breakpoints using fluorescence in situ hybridization (FISH) with region-specific BAC clones revealed a more complex character for the CCR. The rearrangement is a result of nine breaks and involves reciprocal translocation of terminal chromosome fragments 3p24.1-->pter and 12q23.1-->qter, insertion of four fragments of the long arm of chromosome 12: q14.1-->q21?, q21?-->q22, q22-->q23.1, and q23.1-->q23.1 and a region 3p22.3-->p24.1 into chromosome 3q26.31. In addition, we detected a approximately 0.5-Mb submicroscopic deletion at 3q26.31. The deletion involves the chromosome region that has been previously associated with Cornelia de Lange syndrome (CdLS) in which a novel gene NAALADL2 has been mapped recently. Other potential genes responsible for intellectual deficiency disrupted as a result of patient's chromosomal rearrangement map at 12q14.1 (TAFA2), 12q23.1 (METAP2), and 11p14.1 (BDNF).

[Epilepsy in three children with Wolf-Hirschhorn syndrome]

OBJECTIVES

Wolf-Hirschhorn syndrome (4p detetion) belongs to the group of disorders caused by chromosomal aberrations, associated with frequent occurrence of epilepsy. To illustrate phenotype - genotype association, the study presents 3 children with this syndrome and epilepsy.

MATERIALS AND METHODS

The diagnosis of Wolf-Hirschhorn syndrome was established in 2 patients during neonatal period and in the third child, the 5 month of life. In the majority of patients characteristic phenotype and associated malformations were detected, and the low birth weight and fronto-temporal diameter of the head as well. The structural neuroimaging revealed the diffuse decrease of brain volume without neurodevelopmental malformations. The earliest manifestation of epilepsy was observed in the 4 month old child with 4p. microdeletion as a status epilepticus. In remaining two children with 4p deletion, generalised tonic-clonic seizures were observed for the first time in the 7th month and 7th year, respectively. The standard EEG was performed in infants, while in the 7 year old child a-one-hour videoEEG was recorded.

RESULTS

In older children diazepam and clona-zepam were effective to abort seizures, patients became seizure free on carbamazepin and phenobarbital. In the youngest child, status epilepticus being resistant to benzodiazepins, was interrupted with difficulties. Despite generalised type of seizures, EEG revealed focal changes of bioelectrical activity of the brain in two children. In the 7 month old child there were high voltage slow waves in the parieto-temporo-occipital region, while in the 7 year old child videoEEG demonstrated inter-hemispheric asymmetry and asynchrony, and the presence of epileptic grapho-elements, such as spikes and the spike-slow wave complexes as well.

CONCLUSION

Epilepsy appeared in children with Wolf-Hirschhorn syndrome with deletion and microdeletion. Status epilepticus in this syndrome may be resistant to benzodiazepins.

The presence of hereditary BRCA1 gene mutations in women with familial breast or ovarian cancer and the frequency of occurrence of these tumours in their relatives

In 48 women with familial breast cancer as well as in 22 women with familial ovarian cancer, the presence of pathogenic mutations in BRCA1 gene were found in 35.4% and 54.6% of patients, respectively. From the patients with mutations we created two groups: the CaM--probands with breast cancer and CaOv--probands with ovarian cancer. The probands with breast cancer were younger by a mean of five years than the probands with ovarian cancer (p = 0.048).

METHODS

The PCR-SSCP procedure was used to find mutations in the BRCA1 gene. Fragments suspected of mutation were subjected to nucleotide sequencing.

RESULTS

In the CaM group, which consisted of 17 women with breast cancer, the following mutations in the BRCA1 gene were detected: 5382insC, T300G, 3819del5 and IVS20+60ins12. The probands of the CaM group and their relatives developed a total of 49 breast and ovarian cancers. Among all these tumours the breast cancers of the probands made up 34.7%, the breast cancers of proband relatives made up 57.1% and the ovarian cancers of probands and their relatives made up only 8.2%. The CaOv group consisted of 12 probands with ovarian cancers in whom we detected only two kinds of mutations: 5382insC and 185delAG. The probands of the CaOv group and their relatives developed a total of 38 ovarian and breast cancers. Among all these tumours the ovarian cancers of the probands made up 31.6%, the ovarian cancers of their relatives made up 34.2% and the breast cancers of the relatives 34.2% of tumours. In the probands with breast or ovarian cancer the predominant mutation was 5382insC--in the BRCA1 gene detected in 76.5%, and 91.7%, respectively. Despite the predominant presence of the same mutation in probands from both groups the ratio of the number of breast cancers to the number of ovarian cancers in their relatives differed significantly (p = 0.0003).

CONCLUSION

This data shows that the presence of the 5382insC mutation in the BRCA1 gene is not always associated with the development of ovarian cancer. It is very likely that the development of ovarian cancer requires some additional factor, which was common among the familial ovarian cancer patients, and was almost inexistent among the familial breast cancer patients. On the other hand, the development of ovarian cancer at a later age than breast cancer in probands suggests that some factors exist which slow down the development of ovarian cancer or which accelerate the development of breast cancer.

Frequent disease progression and early recurrence in patients with familial ovarian cancer primarily treated with paclitaxel and cis- or carboplatin (preliminary report)

PURPOSE

To evaluate frequencies of early disease progressions and recurrences in patients with familial vs sporadic ovarian cancers following primary paclitaxel/cis- or carboplatin chemotherapy.

METHODS

The frequencies of disease progression up to six months following primary paclitaxel/cis- or carboplatin and of early disease recurrences were analysed in 18 Stage III patients with familial ovarian cancers, both carriers and non-carriers of 5382 insC BRCA1 mutation, and in 35 patients with Stage III sporadic ovarian tumors.

RESULTS

Progressive disease within first six months following chemotherapy developed in 5/18 patients with familial cancers vs. 5/35 patients with sporadic tumors. Early disease recurrences (up to 6 months after treatment) occurred in 3/18 patients with familial vs. 2/35 patients with sporadic tumors. Recurrences after 7-12 months following treatment occurred, respectively, in 3/13 and 3/31 patients from these groups.

CONCLUSION

The results of this preliminary report may suggest that patients with familial ovarian tumors respond less favourably to paclitaxel/cis- or carboplatin treatment than patients with sporadic ovarian tumors. These findings should be however confirmed in a prospective study on a larger group of patients.

[Thanatophoric dysplasia: three patients hospitalized in PAIP in 1994-2000]

BACKGROUND

Thanatophoric dwarfism is a lethal bone dysplasia causing severe disturbance in body proportions, shortening and deformation of the long bones and maldevelopment of the chest leading to severe respiratory failure and early death. The disease is caused usually by de novo mutation in the gene of fibroblast growth factor receptor 3 (FGFR3). Inheritance is autosomal dominant. The most common mutation C742T leads to substitution of arginine by cysteine in 248 position of polypeptide (R248C).

GOAL

Presentation of clinical picture, radiological findings and molecular diagnostics in three patients with TD hospitalized in PAIP in 1994-2000.

PATIENTS

Three patients with TD were hospitalized in PAIP between 1994 and 2000. They were admitted in the 1st, 2nd, 19th day of life. Two patients were referred with diagnosis of achondroplasia. One newborn was born after uncomplicated pregnancy with cesarean section due to large head circumference found on prenatal USG. Two other newborns were born preterm (34 week of gestation), vaginally. One pregnancy was complicated by polyhydramnios. All patients required oxygen therapy, two were artificially ventilated (21 and 16 days). Three newborns died due to respiratory failure, average length of life--29 days.

METHODS AND RESULTS

The diagnosis was established based on clinical presentation (abnormal proportions, shortening and deformation of the extremities, maldevelopment of the chest, large cranium) and radiological presentation (typical vertebral bodies, long bones shaped as telephone receiver). In two cases molecular analysis was performed, which excluded achondroplasia, in one of those patients molecular studies directly confirmed presence of the most common mutation leading to TD (R248C).

Radical hysterectomy for IB cervical cancer in a patient with aorto-femoral transposition

We present a cervical cancer case in stage IB, according to FIGO classification, treated with radical hysterectomy and pelvic lymphadenectomy. The 48-year-old patient had 4 years previously undergone a Y aorto-bifemoral Dallon transposition as a result of Leriche's syndrome. During the routine investigation invasive cervical cancer was diagnosed. She had radical hysterectomy of Piver III type and partial pelvic lymphadectomy. Radical hysterectomy caused no technical trouble. Pelvic lymphadenectomy was only partially possible because of hard connective tissue around the artificial vessels. This scarred region made safe preparation of the total pelvic lymphatic system impossible.

[Giant placental angioma with polyhydramnios, high level of alpha-fetoprotein and neonatal congenital lactic acidosis]

Placental tumors are rare in pregnancy. They cause nonspecific complications such as polyhydramnios, fetal anemia, fetal thrombocytopenia and cardiac decompensation with non-immunological hydrops fetalis. In the presented case a very large placental hemangioma was connected with polyhydramnios, premature delivery, fetal anemia and thrombocytopenia, maternal serum alpha fetoprotein elevation and congenital lactic acidosis. After delivery a severe state of the newborn was caused by oligovolemic shock. In the course of the disease the neonatal state steadily deteriorated mainly because of sepsis, cerebral hemorrhage and metabolic acidosis despite adequate therapy. The organic acids assessment in the blood serum of a newborn child showed a very strong signal of lactic acid and an increase in parahydroksyfenylolactic acid. Postmortal examination confirmed prematurity, respiratory distress syndrome, sepsis and cerebral hemorrhage. These symptoms probably resulted from the presence of a placental tumor of considerable size of 12 cm and congenital lactic acidosis, which to our knowledge, have not been described in the available literature until now. In conclusion it should be underlined, that there exists difficult to explain relationship between the presence of a placental haemangioma and severe metabolic changes resulting in high mortality and morbidity of the newborn.

[A case of extended hysterectomy in stage IB-1 cervical cancer after aorto-bifemoral reconstruction]

We describe a cervical cancer case stage IB-1 according to FIGO classification surgically treated with extended hysterectomy and lymphadenectomy. The patient was four years after aorto-femoral Dallon bypass on account of Leriche syndrome and from this time she was treated with oral anticoagulant therapy. During the routine diagnostic investigations the invasive cervical cancer IB-1 was diagnosed. According to the oncological protocol she has had extended hysterectomy Piver III type and partial pelvic lymphadenectomy. Extended hysterectomy did not cause technical troubles. Pelvic lymphadenectomy was only partially possible to realizing. Compact connective tissue around the artificial vessels did not permit safe preparation of pelvic lymphatic system.