Clinical and genetic features of 13 patients with mucopolysaccarhidosis type IIIB: Description of two novel NAGLU gene mutations

Aim

Mucopolysaccharidosis type III B (MPS IIIB) is an autosomal recessive lysosomal storage disease caused by mutations in the NAGLU gene which codes the lysosomal enzyme alpha-N-acetylglucosaminidase. The major symptoms of the disease are cognitive and neurological defects. In this study, the molecular spectrums of 13 MPS IIIB patients were evaluated.

Material and methods

Thirteen MPS IIIB patients from 11 families were included in this study. All patients were both clinically and molecularly diagnosed. NAGLU gene sequencing was performed using a next generation sequencing platform (Illumina MiSeq). Demographic, clinical and laboratory findings of the patients were obtained via the hospital records.

Results

Ten different mutations from the 13 MPS IIIB patients were identified. Eight of the 10 mutations were missense, one was splice site, and one large deletion was also observed. Two mutations c.509G>T (p.Gly170Val) and c.700C>G (p.Arg234Gly) have been defined for the first time in this study.

Conclusion

Our study expanded the mutation spectrum of the NAGLU gene thereby contributing to the improved genetic counselling of MPS IIIB patients. Confirming the literature, missense mutations were also found to be the most common NAGLU mutations in our study.

GENETIC COUNSELLING IN FEINGOLD SYNDROME AND A NOVEL MUTATION

Feingold syndrome (FS) is an autosomal dominant hereditary disorder characterised by finger and toe abnormalities, microcephaly, facial dysmorphism, gastrointestinal atresias such primarily as oesophageal and/or duodenal atresia and mild to moderate mental retardation. Approximately 60% of cases have an affected parent. MYCN is the only gene in which mutations are known to cause FS. In this report, we present a case with Feingold Syndrome having a novel mutation in MYCN gene and discuss genetic counselling and prenatal diagnosis due to pregnancy of the patient's mother.

TWINS WITH KLEEFSTRA SYNDROME DUE TO CHROMOSOME 9q34.3 MICRODELETION

Kleefstra or 9q subtelomeric deletion syndrome (9qSTDS) is a rare microdeletion syndrome. The most prominent phenotypic features include hypotonia, developmental retardation, as well as typical dysmorphic face. It has been shown that terminal deletions of the chromosome 9q34.3 region, or EHMT1 gene mutations, lead to Kleefstra syndrome. We present 16-month-old twin sisters, one of whom had originally been referred for Down syndrome screening due to hypotonia, growth and development retardation, dysmorphic facial signs, and accompanying congenital heart disease. They were subsequently diagnosed as Kleefstra syndrome based on subtelomeric FISH analysis. In conclusion, Kleefstra syndrome should be considered in the differential diagnosis of Down syndrome because it presents with very similar phenotypic features.

Results of fifteen-year follow-up from a single center: findings and risks for tumor development in isolated hemihyperplasia cases

Isolated hemihyperplasia is abnormal asymmetric growth of one or more parts of the body without any underlying disease. The risk for the development of embryonal tumor is increased in the subjects with isolated hemihyperplasia. The study presented here retrospectively evaluated the clinical data and the risk for tumor development in the cases with isolated hemihyperplasia. 24 cases with isolated hemihyperplasia were retrospectively evaluated. An extremity segment has been involved in 16.7%, an extremity has been entirely involved in 37.5%, more than one extremity have been involved on the same side in 16.7%, and definitely half of the body including the face has been involved in 25% of the patients, whereas one side of the face has been involved in only one case. Wilms tumor in the left abdomen (4.2%) was developed in one case. Isolated hemihyperplasia is a rare clinical picture that enhances the risk for the development of embryonal tumors.

A twin sibling with Prader-Willi syndrome caused by uniparental disomy conceived after in vitro fertilization

The use of assisted reproductive technologies (ART) has increased gradually in the treatment of infertility worldwide. On the other hand ART has been found to be associated with an increased risk of congenital malformations including imprinting defects as well. Although a number of imprinting syndromes have been reported to be related with ART, no case with uniparental disomy (UPD) caused Prader-Willi syndrome (PWS) [OMIM ID: 176270] has been reported in the literature. Here we present a dizygotic twin in which one of them was born with maternal UPD15 following ART. The proband was a 2-year-old boy who had feeding difficulties, generalized hypotonia, frontal bossing, broad forehead, small hands and feet. Laboratory investigations revealed minimal dilatation in 3rd and 4th ventricles and corpus callosum hypoplasia in magnetic resonance imaging, supravalvular pulmonary stenosis in echocardiography and pelvicaliectasia in the USG examinations. Methylation and microsatellite markers analyses showed maternal UPD for chromosome 15. Here we report, for the first time UPD caused PWS patient born after ART.

Feasibility of an endoscopic approach to the axillary nerve and the nerve to the long head of the triceps brachii with the help of the Da Vinci Robot

Surgery to transfer the axillary nerve and the nerve of the long head of the triceps presents two obstacles: 1) the access portals are not standardized and 2) the nerves are for their larger part approached through large incisions. The goal of this study was to explore the feasibility of an endoscopic microsurgical approach. The posterior aspect of a cadaver shoulder was approached through three communicating mini-incisions. The Da Vinci robot camera was installed on a central trocart, and the instrument arms on the adjacent trocarts. A gas insufflation distended the soft tissues up to the lateral axillary space. The branches of the axillary nerve and the nerve to the long head of the triceps brachii muscle were identified. The dissection of the axillary nerve trunk and its branches was easy. The posterior humeral circumflex veins and artery were dissected as well without any difficulty. Finding the nerve to the long head of the triceps brachii was found to be more challenging because of its deeper location. Robots properties allow performing conventional microsurgery: elimination of the physiologic tremor and multiplication of the movements. They also facilitate the endoscopic approach of the peripheral nerves, as seen in our results on the terminal branches of the axillary nerve and the nerve to the long head of the triceps brachii.

Partial trisomy 2p24-->pter and monosomy 18q22.1- qter resulting from parental translocation

This is a report of a 6 month-old boy with a partial trisomy 2p24-->pter and monosomy 18q22-->qter. This is the first case presenting this unbalanced translocation with phenotypic features. The patient had growth and developmental retardation, facial dysmorphism, cleft palate, congenital cardiopathy, hypospadias, evantration of diaphragm and deafness. Cranial MRI showed mild ventricular dilatation. Cytogenetic analysis of the patient and his parents revealed a karyotype 46,XY, der(18), t(2;18)(p24;q22)mat in the patient. Subtelomeric FISH analysis confirmed the cytogenetic findings. Phenotypic features were consistent with either partial trisomy 2p or deletion 18q.

Subtelomeric rearrangements in patients with idiopathic intellectual disabilitiy/ multiple congenital anomalies and recurrent miscarriages: seven years' experience

Cryptic subtelomeric anomalies are a significant cause of idiopathic intellectual disability and/or multiple congenital anomalies (ID/MCA) and multiple miscarriages (MM). Effective preselection of patients is essential as the cost of subtelomeric testing is high and it is labor-intensive. Therefore, the aim of this study is to evaluate the frequency of subtelomeric anomalies by using commercial FISH probes in 151 patients of ID/MCA and 32 couples with MM who were referred to a genetic center during 7-year period and to determine whether performing subtelomeric testing is feasible for these groups of patients. We assessed the clinical information of all referrals including family history, physical examination, facial dysmorphism, congenital malformations and scored the ID/MCA patients according to the criteria suggested previously. The etiology was not elucidated and all patients had normal karyotypes. Subtelomeric deletions were found in 10 patients in ID/MCA group (6.62%). These were deletions of 14qter (2 patients), 18qter (2 patients), 18pter (2 patients), 15qter, 7pter, 8pter and 4qter. The clinical information of all patients having deletions has been summarized and confined with the current literature. No anomaly was detected in the MM group. In conclusion, the prevalence of subtelomeric anomalies in ID/MCA group in this study is consistent with the literature and subtelomeric FISH analysis is feasible in determining their etiology when a checklist is used. Besides, assessment of the genetic basis of ID/MCA had lead the prevention of the recurrence of such conditions in selected families as well as elucidating novel genetic causes of ID.

A Comparison of Efficacy Between Two Natural Exogenous Surfactant Preparations in Premature Infants with Respiratory Distress Syndrome

The mortality and various morbidity rates have been substantially reduced by means of exogenous surfactant replacement, the cornerstone in the treatment of respiratory distress syndrome (RDS) in premature infants. The objective of this study is to compare two natural surfactant preparations (Alveofact(R), Survanta(R)) in terms of effectiveness and side-effects. A total of 50 infants with RDS were given surfactant due to RDS were taken into the scope of this study. Survanta(R) and Alveofact(R) were administered to randomized infants with RDS and the results obtained during clinical observations were compared. Second hour mean FiO (2), MAP and a/APO (2) values showed changes in favour of Alveofact(R) (n = 25) group compared to the Survanta(R) (n = 25) group (p < 0.05 for each parameter). However, this difference disappeared in the 6 (th) hour. No statistical difference was established between the two groups with regard to sideeffects (pneumothorax, sepsis, intraventricular hemorrhage, bronchopulmonary dysplasia), duration of mechanical ventilation in survivors, duration of hospitalization in survivors and mortality before the 28 (th) day. It was concluded that results obtained with different surfactant preparations having dissimilar compositions were not different in terms of final impacts and side-effects.

A comparison of blood loss and transfusion requirements in total knee arthroplasty with and without arterial tourniquet

A retrospective study was undertaken to determine the intraoperative blood loss and the subsequent need for blood transfusion in primary total knee arthroplasty. Fifty-six patients were operated on with the use of an arterial tourniquet (group 1), and 50 patients, without the use of a tourniquet (group 2). The mean intraoperative blood loss was significantly different between the two groups (P = 0.001). The 1-hour postoperative hemoglobin decrease was also significantly different between the two groups (P = 0.006). Thirty-four patients (61%) in group 1, and 32 patients in group 2 (64%) required a blood transfusion prior to discharge from the hospital. This difference was not significantly different. Although intraoperative blood loss was increased in the group when no tourniquet was used, the overall incidence of transfusion was the same between the two groups. It may therefore be justified to question the routine use of a tourniquet during total knee arthroplasty.

Fracture blister formation: a laboratory study

A biomechanical study was performed to examine a proposed mechanism of fracture blister formation. Sixty cadaver ankle skin specimens were subjected to several levels of uniaxial strain and examined histologically. Dermal-epidermal separation patterns similar to those found histologically in previous studies of biopsied fracture blisters were seen in specimens strained 152% and greater. These findings support the hypothesis that fracture blisters can result from strain developed in the skin during initial fracture deformation.