An unusual mutation in RECQ4 gene leading to Rothmund-Thomson syndrome.

Rothmund-Thomson syndrome (OMIM #268400) is a severe autosomal recessive genodermatosis: characterised by growth retardation, hyperpigmentation and frequently accompanied by congenital bone defects, brittle hair and hypogonadism. Mutations in helicase RECQ4 gene are responsible for a subset of cases of RTS. Only six mutations have been reported, thus, far and each affecting the coding sequence or the splice junctions. We report the first homozygous mutation in RECQ4 helicase: 2746-2756-delTGGGCTGAGGC in IVS8 responsible for the severe phenotype associated with RTS in a Malaysian pedigree. We report also a 5321 G-->A transition in exon 17 and the updated list of the RECQ4 gene mutations.

Chromosomal instability in fibroblasts and mesenchymal tumors from 2 sibs with Rothmund-Thomson syndrome.

Rothmund-Thomson syndrome (RTS) is a rare autosomal recessive genodermatosis associated with increased risk of mesenchymal tumors. The putative gene has been provisionally assigned to chromosome 8. Using a cytogenetic-molecular approach, we studied lymphocytes, fibroblasts, osteosarcoma (OS) and malignant fibrous histiocytoma (MFH) from 2 affected fraternal twins, looking for constitutive markers of chromosome instability and tumor chromosomal changes which might reflect the common genetic background. The rate of spontaneous chromosome aberrations was not increased in lymphocytes. Conversely, karyotyping of primary fibroblasts from one sib evidenced chromosome breaks and both numerical and structural chromosome changes in 24% and 17% of the metaphases respectively. FISH of a 8q21.3 cosmid allowed us to detect trisomy of the target region on 7% of fibroblast nuclei from both sibs, 47% and 12% of OS and MFH cells. Pronounced chromosomal instability and clonal rearrangements leading to different chromosome-8 derivatives were detected in both tumors. CGH experiments showed multiple gains/losses, among which del(6q), also revealed by cytogenetics, and 7p gain were common, whereas 8q amplification was present only in OS. Chromosomal instability, observed in fibroblasts from the RTS patients studied, accounts for the increased risk of mesenchymal tumors in these patients.

A clinical audit on the practice of platelet transfusions at a tertiary paediatric referral centre.

Platelet transfusions are indicated in a wide variety of clinical conditions especially those with thrombocytopenia. However, without proper clinical practice guidelines, inappropriate transfusions are bound to happen. To ascertain the provision of a quality and appropriate practice of platelet transfusions, an audit study was carried out over a period of one month at the Paediatric Institute, Kuala Lumpur Hospital. A prospective audit was performed during that period whilst a retrospective collection of data was carried out for the previous month for comparison. Based on a set of criteria agreed upon by the audit committee, it was found that in 18.5% (22 of 119) of the cases, the indications for platelet transfusions were inappropriate. The audit committee concluded that there is a need for a more detailed clinical practice guideline for local use to reduce or lower the incidence of inappropriate transfusions of platelets.

Ocular involvement in acute lymphoblastic leukaemia.

A six-year-old boy, a known case of acute lymphoblastic leukaemia (ALL) on remission since 1991 presented with leukocoria and poor vision of the left eye for two days' duration. Examination revealed endophthalmitis in the left eye with raised intraocular pressure. Anterior chamber paracentesis with vitreous biopsy confirmed a diagnosis of ocular involvement. Further investigation revealed that he also had bone marrow and central nervous system relapse. Clinical manifestation and treatment modalities of ocular involvement in leukaemia are discussed.

Homozygous beta-thalassaemia: a review of patients who had splenectomy at the Royal Alexandra Hospital for Children, Sydney.

Twenty-four patients with homozygous beta-thalassaemia who had been splenectomised and currently on treatment were studied retrospectively. They were divided into two groups. Group A: who had splenectomy prior to commencement of any regular blood transfusion. The mean haemoglobin for this group rose from 5.5 gm/dl pre-splenectomy to 7.7 gm/dl post splenectomy (p < 0.001). Group B: who were on regular blood transfusion when they had their splenectomy and the mean blood transfusion requirement dropped from 317 ml/kg/yr to 230 ml/kg/yr of packed red cells following splenectomy (p < 0.001). Three patients who were on regular blood transfusion and desferrioxamine developed Yersinia enterocolitica infection. They presented with fever and signs of an acute abdomen. At laparotomy, 2 of the patients had acute appendicitis. All 3 appendices grew Yersinia enterocolitica and one patient also had a Yersinia enterocolitica septicaemia. If a patient develops fever and enteritis, desferrioxamine should be stopped temporarily and cotrimoxazole started as prophylaxis against systemic Yersiniosis. No cases of pneumoccocal sepsis was reported.

All trans-retinoic acid in the treatment of promyelocytic leukaemia--a case report.

A six year old Chinese boy with relapsed Acute Promyelocytic Leukaemia (APML) failed to respond to reinduction with Daunorubicin and Cytarabine infusion. He was successfully treated with all trans-Retinoic Acid (45 mg/m2/day) orally. After four weeks of treatment, he was in complete remission. The side effects of all trans-Retinoic Acid were negligible.

Cardiovascular malformations in Malaysian neonates with Down's syndrome.

A prospective study was done to determine the incidence of cardiovascular malformations in neonates with Down's syndrome. 17/34 (50%) of the babies with Down's syndrome born at the Maternity Hospital, Kuala Lumpur, Malaysia had congenital heart defects. These included 7 cases of ventricular septal defect (VSD), 3 cases of patent ductus arteriosus (PDA), 2 cases of atrio-ventricular canal defect, 2 cases of ventricular septal defect with patent ductus arteriosus, 1 case of hypertrophic cardiomyopathy, 1 case of hypertrophic obstructive cardiomyopathy and 1 case of complex cyanotic heart. Only 8/17 (47%) of these babies had any clinical signs suggesting underlying cardiac defects. In view of the common occurrence of cardiac anomalies, it is recommended that echocardiographic screening should be carried out on all neonates with Down's syndrome.

Incidence of Down's syndrome in a large Malaysian maternity hospital over an 18 month period.

Over an 18 month period, 34,522 livebirths were delivered in the Maternity Hospital, Kuala Lumpur. 36 of them had Down's Syndrome. Based on our findings, the incidence of Down's syndrome among the Malaysian babies born in this hospital was 1:959 livebirths. According to racial distributions, the incidence among Malay was 1:981 livebirths, Chinese 1:940 livebirths, and Indian 1:860 livebirths. Our incidence was lower than those from the Western populations. Unlike others' studies, there was also a female preponderance of Down's syndrome among the Malaysian babies.

Maternal age-specific incidence of Down's syndrome in Malaysian neonates.

Over an 18 month period, 34,495 livebirths were delivered in the Kuala Lumpur Maternity Hospital. 36 neonates (1.044 per 1000 livebirths) had Down's syndrome. The observed rates of Down's syndrome per 1000 livebirths by single year intervals of maternal age were calculated. By using the discontinuous slope model, our study showed that the incidence of Down's syndrome among the Malaysian liveborns increased markedly when the maternal age exceeded 35 years. This study also suggested that the Malay mothers had increased risk of producing babies with Down's syndrome at a later age than the Chinese and the Indians. However, a larger number of babies in each racial group needs to be studied to confirm this.