The Q359K/T360K mutation causes cystic fibrosis in Georgian Jews

BACKGROUND

The Q359K/T360K mutation, described in Jewish CF patients of Georgian decent, is of questionable clinical significance.

METHODS

Clinical records of patients with the Q359K/T360K mutation from three CF centers were studied for phenotypic expression and putative mechanism of dysfunction. Computer models of mutant CFTR were constructed.

RESULTS

Nine patients (4 homozygous) of Georgian Jewish origin were included. Age at diagnosis was 9.4 (0.25-38.2) years, median (range). Sweat chloride was 106 ± 13 meq/L, mean ± SD. Nasal Potential Difference performed in three, was abnormal. All had pulmonary symptoms since early childhood and bronchiectasis. Median FEV₁ was 88 (40-121)%. Five had chronic mucoid P. aeruginosa. Homozygous patients were pancreatic insufficient. Enzyme supplementation was initiated at 3.8 (1-14.7) years, median (range). Structural models hint at possible interference of this mutation with transmembrane chloride transport.

CONCLUSION

In our cohort, the Q359K/T360K mutation resulted in a severe CF phenotype, although with residual early CFTR function. The CFTR2 database should consider defining this mutation as CF-causing.

Computerised paediatric asthma quality of life questionnaires in routine care

BACKGROUND

Asthma quality of life questionnaires are not readily incorporated into clinical care. We therefore computerised the Paediatric Asthma Quality of Life Questionnaire (standardised) (PAQLQ(S)) and the Paediatric Asthma Caregivers Quality of Life Questionnaire (PACQLQ), with a colour-coded printed graphical report.

OBJECTIVES

To (a) assess the feasibility of the electronic questionnaires in clinical care and (b) compare the child's PAQLQ scores with the parent's score, physician's clinical score and spirometry.

METHODS

Children with asthma were given a clinical severity score of 1-4 (increasing severity) and then completed the PAQLQ(S) electronically (scores 1-7 for increasing quality of life in emotional, symptoms and activity limitation domains) followed by spirometry and physician review. Parents completed the PACQLQ. Inclusion criteria required fluent Hebrew and reliable performance of spirometry. Children with additional chronic diseases were excluded.

RESULTS

147 children with asthma aged 7-17 years completed PAQLQs and 115 accompanying parents completed PACQLQs, taking 8.3 (4.3-15) and 4.4 (1.5-12.7) min, respectively (mean (range)). Graphical reports enabled physicians to address quality of life during even brief visits. Children's (PAQLQ) and parents' (PACQLQ) total scores correlated (r = 0.61, p<0.001), although the children's median emotional score of 6.3 was higher than their parents' 5.7 (p<0.001), whereas median activity limitation score was lower than their parents': 5.0 and 6.8, respectively (p<0.001). No correlation was found with physician's clinical score or spirometry.

CONCLUSIONS

Electronic PAQLQs are easy to use, providing additional insight to spirometry and physician's assessment, in routine asthma care. Future studies must assess impact on asthma management.

Cystic fibrosis mutations with widely variable phenotype: the D1152H example

D1152H is a type IV cystic fibrosis transmembrane regulator (CFTR) mutation associated with abnormal chloride gating. Although comprising 5-6% of mutations on genetic screening, clinical reports of cystic fibrosis (CF) are rare, suggesting that the disease is mild, atypical, or even absent. We describe our experience, which contrasts with this assumption, in a retrospective case series encompassing 91 CF patients (74 Jewish) aged 8 months to 56 years, from 2000-2005. Nine patients of varied Jewish ethnic origins were homozygous (2 patients) or compound heterozygous for D1152H with 11 of 182 potential alleles (6%). Five were diagnosed at age 33-49 years. Of 4 infants, 1 was diagnosed by prenatal screening, 1 had a prenatal dilated bowel, and 1 had pulmonary symptoms. Sweat chloride was 28-120 meq/l. Three adults had chronic mucoid Pseudomonas aeruginosa in sputum, and a forced expired volume in 1 sec (FEV1) of 20-55%. One was on bilevel positive airway pressure (BIPAP) ventilation. The infants had pulmonary symptoms that responded well to therapy. All 9 patients had good nutrition, 6 were pancreatic-sufficient, and 3 adults had subclinical pancreatic insufficiency. Three adults had recurrent pancreatitis. None had a bowel obstruction. Two of 3 adult males were fertile. Although asymptomatic at times, the D1152H mutation is associated with a broad clinical spectrum. This information is crucial for genetic counseling. Lung disease may be evident from infancy, and is severe in some adults, although all have outlived the median life expectancy of CF. Hopefully, with early diagnosis and therapy, prognosis can be good. A multicenter study of this mutation is warranted.

The prevalence and clinical characteristics of cystic fibrosis in South Asian Canadian immigrants

BACKGROUND

Cystic fibrosis (CF) is considered to be rare among individuals from the Indian subcontinent. Furthermore, affected individuals are reported to experience a more severe clinical course.

AIMS

It was hypothesised that CF is under diagnosed in people of South Asian origin and therefore the prevalence may be higher than previously estimated.

METHODS

The prevalence of CF in the South Asian and in the general population living in the same geographic region (Metropolitan Toronto) were compared between 1996 and 2001. Population data were obtained from the Canadian census survey. CF phenotype and genotype data were obtained from the Toronto CF database.

RESULTS

Among 381 patients with CF, 15 were of South Asian descent. The age related prevalence of CF among the South Asian and general populations was: 0-14 years, 1:9200 versus 1:6600; 15-24 years, 1:13,200 versus 1:7600; older than 25 years, 1:56,600 versus 1:12,400. Age at diagnosis, duration and severity of symptoms at diagnosis, current nutritional status, and FEV(1) were similar in the two groups. While not significant, FEV1 tended to be lower (48% versus 57% predicted) among adult South Asians, compared to the general CF population. Also, the percentage with pancreatic sufficiency was higher (27% versus 16%) and the frequency of DeltaF508 allele was lower (50% versus 65.1%).

CONCLUSIONS

These data suggest that the prevalence and natural history of CF in South Asians is similar to that among individuals of European origin. The relatively lower prevalence among older South Asians may reflect an improving recognition of CF in this ethnic subgroup.

Cystic fibrosis presenting as kwashiorkor in a Sri Lankan infant

Growth failure is a common presentation of patients with pancreatic insufficient cystic fibrosis. However, full blown kwashiorkor is extremely rare. Cystic fibrosis is also considered to be rare in the South Asian population. This report describes a Sri Lankan infant with cystic fibrosis who presented with clinical features of severe kwashiorkor.

Bochdalek diaphragmatic hernia: not only a neonatal disease

AIMS

To characterise the clinical manifestations of late presenting Bochdalek diaphragmatic hernia (DH), the incidence of misdiagnosis, and prognosis; and to explore the sequence of events that leads to this clinical picture.

METHODS

Retrospective chart review. All children with Bochdalek DH were identified. Children 1 month of age and older at the time of diagnosis were included.

RESULTS

Twenty two children with Bochdalek DH met the inclusion criteria. Three clinical presentations could be defined. Fourteen children presented with acute onset of symptoms, predominantly vomiting and respiratory distress. Four had chronic non-specific gastrointestinal or respiratory symptoms, and in four the DH was found incidentally. Although five children were initially misdiagnosed, in 20 children (91%) the correct diagnosis was made on x ray examination. One child experienced a complicated course when the x ray picture was misinterpreted as pneumothorax. All children had favourable outcome. Two children had previously normal chest imaging, suggesting acquired herniation. A large pleural effusion without DH in a 9.5 year old girl with an abdominal infection prior to presenting with herniation suggests a pre-existing defect in the diaphragm.

CONCLUSIONS

Late presenting Bochdalek DH can present with acute or chronic gastrointestinal, or less frequently, respiratory symptoms. It can also be found incidentally. Misdiagnosis can result in significant morbidity. Favourable outcome is expected when the correct diagnosis is made. The sequence of events is probably herniation of abdominal viscera through a pre-existing diaphragmatic defect. Although rare, DH should be considered in any child presenting with respiratory distress or with symptoms suggestive of gastrointestinal obstruction.

Convulsions and retinal haemorrhage: should we look further?

BACKGROUND AND AIMS

The prevalence of retinal haemorrhages after convulsions is not well established. As these haemorrhages are considered characteristic of child abuse, we investigated their occurrence after convulsive episodes to see whether the finding of haemorrhage should prompt further investigation.

METHODS

Prospective study of 153 children (aged 2 months to 2 years), seen in the emergency department after a convulsive episode. After a thorough history and physical examination, a retinal examination was performed by an ophthalmologist. If findings were positive, further investigation was undertaken to rule out systemic disorder or child abuse.

RESULTS

One child was found with unilateral retinal haemorrhages following an episode of a simple febrile convulsion. A thorough investigation uncovered no other reason for this finding.

CONCLUSION

Retinal haemorrhages following a convulsive episode are rare. Such a finding should trigger an extensive search for other reasons, including child abuse.

Ambulatory blood pressure monitoring in children with a solitary kidney - a comparison between unilateral renal agenesis and uninephrectomy

BACKGROUND

In experimental animals, a reduction in renal mass leads to glomerulosclerosis of the residual parenchyma and eventual renal failure. In humans, however, data on the influence of nephrectomy or agenesis on future functional parameters and hypertension are as yet controversial.

OBJECTIVE

To evaluate blood-pressure patterns in children with a solitary kidney as a result of either unilateral renal agenesis (URA) or uninephrectomy (UNX) and correlate them to the increase in size of the remaining kidney.

METHODS

Twenty-eight children with a solitary kidney were divided into two groups: the URA group, with 18 subjects (13 male and five female, with a mean age of 9.6 +/- 3.9 years), and the UNX group, which contained 10 subjects (four male and six female, with a mean age of 14.0 +/- 2.7 years). The mean time since nephrectomy was 8.7 years. Each study group was assigned an age-, weight- and height-matched control group. In all subjects, ambulatory blood pressure monitoring was performed using the SpaceLabs model no. 90207. Daytime and night-time were defined as 0800-2200 h and 2200-0800 h, respectively. Urinalysis, serum creatinine and urea results were recorded for all the study group participants. The size of the remaining kidney was determined by ultrasound examination. The percentage increase in kidney size, as calculated from standard kidney-length-against-age nomograms was correlated to the percentage deviation from normal blood pressure values.

RESULTS

The mean 24 h, daytime and night-time systolic blood pressure (SBP) readings were significantly higher in children in the URA group than in those in the corresponding control group (111.4 +/- 7.5 mmHg versus 106.9 +/- 6.7 mmHg, P < 0.004; 115.2 +/- 3.1 mmHg versus 110.7 +/- 3.4 mmHg, P < 0.004; and 105.2 +/- 2.6 mmHg versus 101.2 +/- 1.8 mmHg, P < 0.002, respectively). Daytime heart rate was found to be significantly reduced (84.4 +/- 5.2 versus 87.8 +/- 8.2 beats/min, P < 0.04). In the UNX group, 24 h mean, systolic and diastolic blood pressure (DBP), as well as heart rate, did not differ from control values. Daytime systolic and diastolic blood pressures were higher than those of the controls (119.8 +/- 4.0 mmHg versus 115.5 +/- 3.8 mmHg, P < 0.02; and 72.7 +/- 4.0 mmHg versus 70.0 +/- 11.0 mmHg, P < 0.02, respectively). Nocturnal dipping was present in all groups and was of equal magnitude in the corresponding control groups. The mean 24 h diastolic blood pressure load was significantly greater in URA patients than in controls (19.6 versus 10.8%, respectively, P < 0.01). In the UNX group, the blood pressure loads were similar to those of controls. The percentage increase in length of the remaining kidney was found to correlate positively with the percentage delta increase in both systolic and diastolic blood pressure.

CONCLUSIONS

Compared with the age-, height- and weight-matched controls, the children with a solitary kidney caused by URA had an elevated mean 24 h SBP. In contrast, those with UNX had mean 24 h blood pressure values similar to those of their controls. A rise in SBP was, however, seen in both groups during the daytime hours. Thus, the presence of a solitary kidney, for whatever reason, may be pathogenetically linked to a raised blood pressure, and this linkage may be more pronounced in URA. The delta increase in size of the remaining kidney may serve as a prognostic indicator of blood pressure elevation.