No evidence of a major locus for benign familial infantile convulsions on chromosome 19q12-q13.1

PURPOSE

A locus for benign familial convulsions (BFICs) has been recently mapped on chromosome 19q12-13.1 by studying five families of Italian descent. The main goal of this study was to investigate the role of this locus in a set of seven newly identified families with at least three affected cases.

METHODS

Five polymorphic microsatellite markers covering the BFIC locus on chromosome 19q have been typed, and parametric linkage analysis has been performed to analyze the segregation of the BFIC locus within our families.

RESULTS

Cumulative 2-point lod scores and multipoint analysis showed no evidence of linkage between chromosome 19 markers and the BFIC phenotype. The analysis of family-specific 2-point lod scores and haplotypes, however, indicated the presence of linkage to chromosome 19q in a single family, suggesting genetic heterogeneity within our family sample.

CONCLUSIONS

Our study demonstrates that the previously reported BFIC locus on chromosome 19q12-13.1 is not a major locus for BFICs. We suggest that genetic heterogeneity may have generated our discordant linkage findings, as it was reported in benign familial neonatal convulsions, a related idiopathic mendelian syndrome.

[Hyponatremia in neurosurgical patients]

Hyponatremia played an essential role in this case, determining the rapid transition from consciousness to a state of coma in female patient who had just come through the critical phase of intensive care. This circumstance underlines the importance of a correct water balance in patients undergoing neurosurgery, as well as a knowledge of the inappropriate antidiuretic hormone secretion (SIADH) syndrome responsible, either alone or in association, for the genesis of severe hyponatremia. In the differential diagnosis of hyponatremia, it is important to recall the role of an often mistaken syndrome (cerebral salt wasting syndrome) characterized by the secretion of a natriuretic factor that has still not been clearly identified.

[Giromitra syndrome caused by false morel]

Three cases of mushrooms poisoning (by false morel) with associated gyromitra syndrome, due to a thermolabil toxin are reported. They showed a syndrome like to Amanita phalloides poisoning (gastroenteric symptomatology, diarrhoea) some hours after eating and then neurologic signs; they were hospitalized (without haemolytic signs) and were discharged from hospital a few days later in a good health.

TRF1 binds a bipartite telomeric site with extreme spatial flexibility

TRF1 is a key player in telomere length regulation. Because length control was proposed to depend on the architecture of telomeres, we studied how TRF1 binds telomeric TTAGGG repeat DNA and alters its conformation. Although the single Myb-type helix-turn-helix motif of a TRF1 monomer can interact with telomeric DNA, TRF1 predominantly binds as a homodimer. Systematic Evolution of Ligands by Exponential enrichment (SELEX) with dimeric TRF1 revealed a bipartite telomeric recognition site with extreme spatial variability. Optimal sites have two copies of a 5'-YTAGGGTTR-3' half-site positioned without constraint on distance or orientation. Analysis of binding affinities and DNase I footprinting showed that both half-sites are simultaneously contacted by the TRF1 dimer, and electron microscopy revealed looping of the intervening DNA. We propose that a flexible segment in TRF1 allows the two Myb domains of the homodimer to interact independently with variably positioned half-sites. This unusual DNA binding mode is directly relevant to the proposed architectural role of TRF1.

Effects of the peroxisome proliferator clofibric acid on superoxide dismutase expression in the human HepG2 hepatoma cell line

We examined the effects of clofibric acid, a peroxisome proliferator, on the production of superoxide radicals, on the levels of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), and on the expression of superoxide dismutases (SODs) in the human HepG2 hepatoma cell line. To this end, HepG2 cells were treated for 1 or 5 days with 0.25, 0.50, or 0.75 mM clofibric acid. The production of superoxide radicals was only enhanced in HepG2 cells exposed for 5 days to the different clofibric acid concentrations. However, this overproduction of superoxide radicals was not accompanied by increased rates of lipid peroxidation, as the MDA and 4-HNE levels did not change significantly. Manganese (Mn) SOD activity was increased when HepG2 cells were treated for 1 day with 0.50 or 0.75 mM clofibric acid. For this duration of treatment, no change was observed in total SOD and copper/zinc (Cu/Zn) SOD activities. For a 5-day treatment, total SOD and MnSOD activities as well as the enzyme apoprotein and MnSOD mRNA levels increased whatever the clofibric acid concentration used. This transcriptional induction of the MnSOD gene was correlated with an activation of the activator protein-1 transcription factor for 1 and 5 days of treatment, but was independent of nuclear factor-kappa B and of peroxisome proliferator-activated receptor. On the other hand, the PP exerted very little effect if any on Cu,ZnSOD expression. In contrast to rodent data, PP treatment of human hepatoma cells induces MnSOD expression.

1,4-Dihydropyridine calcium channel blockers inhibit plasma and LDL oxidation and formation of oxidation-specific epitopes in the arterial wall and prolong survival in stroke-prone spontaneously hypertensive rats

BACKGROUND AND PURPOSE

Calcium-channel blockers (CCBs) reduce systolic blood pressure and stroke-related mortality in stroke-prone spontaneously hypertensive rats (SPSHR). Brain ischemia is associated with loss of intracellular antioxidants. Increased formation of oxygen radicals and oxidation of LDL may enhance arterial vasoconstriction by various mechanisms. CCBs that also exert antioxidative properties in vitro may therefore be particularly useful. To investigate such antioxidant effects in vivo, we determined several parameters of LDL oxidation in SPSHR treated with two 1,4-dihydropyridine-type (1,4-DHP) CCBs of different lipophilic properties and compared them with antioxidant-treated and untreated controls. We also tested whether these drugs decrease the formation of oxidation-specific epitopes in arteries.

METHODS

Five groups of 9 to 14 SPSHR each (aged 8 weeks) were treated with 80 mg/kg body wt per day nifedipine, 1 mg or 0.3 mg/kg body wt per day lacidipine, vitamin E (100 IU/d), or carrier for 5 weeks. A group of Wistar-Kyoto rats was used as normotensive control. Plasma samples were taken, and LDL was isolated by ultracentrifugation. Then LDL was exposed to oxygen radicals generated by xanthine/xanthine oxidase reaction (2 mmol/L xanthine+100 mU/mL xanthine oxidase), and several parameters of oxidation were determined. The presence of native apolipoprotein B and oxidation-specific epitopes in the carotid and middle cerebral arteries was determined immunocytochemically.

RESULTS

1,4-DHP CCBs completely prevented mortality. Normotensive Wistar-Kyoto rats showed less oxidation than control SPSHR. Plasma lipoperoxide levels were 0.87+/-0.27 micromol/L in control SPSHR, 0.69+/-0.19 and 0.63+/-0.20 micromol/L in the groups treated with 0.3 and 1 mg lacidipine, respectively, and 0.68+/-0.23 micromol/L in nifedipine-treated animals (P<0.05 versus control SPSHR for all values). Both CCBs significantly decreased formation of conjugated dienes and prolonged the lag time in LDL exposed to oxygen radicals. Similarly, lipoperoxides and malondialdehyde were significantly reduced (P<0.05). Reduced relative electrophoretic mobility and increased trinitrobenzenesulfonic acid reactivity of LDL from treated rats (P<0.01) also indicated that fewer lysine residues of apolipoprotein B were oxidatively modified in the presence of 1,4-DHP CCBs. Finally, these drugs reduced the intimal presence of apolipoprotein B and oxidized LDL (oxidation-specific epitopes) in carotid and middle cerebral arteries.

CONCLUSIONS

In the SPSHR model, 1,4-DHP CCBs reduce plasma and LDL oxidation and formation of oxidation-specific epitopes and prolong survival independently of blood pressure modifications. Our results support the concept that the in vivo protective effect of these drugs on cerebral ischemia and stroke may in part result from inhibition of oxidative processes.

Experience with longitudinal intestinal lengthening and tailoring

Over a 16-year period, 20 neonates and infants with short-bowel syndrome underwent longitudinal intestinal lengthening and tailoring because of a dysfunctional dilated jejunum. There was no operative mortality, and morbidity was limited to 2 hemiloop anastomotic stenoses and 1 spontaneously resolving air and bile leak. Long-term survival was 45%. Survivors had >40 cm residual jejunum and a greater number also retained their ileocaecal valve and a longer colonic length. They underwent bowel lengthening at a later time and had minimal hepatic dysfunction. 7 of 9 survivors established full enteral nutrition. These children could be regarded as self-selected survivors with residual bowel dysfunction who had come through the hazardous neonatal phase with minimal hepatic injury. Non-survivors often had <40 cm jejunum and limited distal colon. Death was commonly due to end-stage liver failure. It is likely that the severely reduced gut-associated lymphoid tissue contributed to increased bacterial translocation from the dilated bowel and early onset of progressive liver injury. It is possible to conclude that bowel lengthening should be offered only to self-selected survivors with residual bowel dysfunction and minimal liver injury. It seems, however, even more appropriate, to offer early bowel tailoring and lengthening with its recognized reduction in stasis and bacterial translocation, improved absorption and enhanced intestinal adaption, particularly to those high-risk neonates with <40 cm of dilated jejunum with a view to reducing the risk of infection and lethal hepatic injury, thereby improving their chances for quality survival.

Necrotizing enterocolitis in omphalopagus conjoined twins

Female omphalopagus twins underwent laparotomy on the second day of life after an antenatally diagnosed high jejunal bowel obstruction. Bowel resection and choldocho-enterostomies were performed. Despite recovery from laparotomy, the development of severe necrotizing enterocolitis (NEC) in one twin led to rapid deterioration and the death of both infants on day 34. The elucidation of the combined biliary tree, the dilemma of NEC in conjoined twins, and the possibilities of emergency separation are discussed. Consideration should be given to emergency separation of conjoined twins in the event of potentially lethal complications.

Ku binds telomeric DNA in vitro

Ku is a heterodimeric protein with high binding affinity for ends, nicks, and gaps in double-stranded DNA. Both in mammalian cells and in budding yeast, Ku plays a role in nonhomologous end joining in the double strand break repair pathway. However, Ku has a more significant role in DNA repair in mammalian cells compared with yeast, in which a homology-dependent pathway is the predominant one. Recently Ku has been shown to be a likely component of the telomeric complex in yeast, suggesting the possibility of a similar role for Ku at mammalian telomeres. However, long single-stranded G-rich overhangs are continuously present at mammalian but not at yeast telomeres. These overhangs have the potential to fold in vitro into G-G base-paired conformations, such as G-quartets, that might prevent Ku from recognizing telomeric ends and thus offer a mechanism to sequester the telomere from the prevalent double strand break repair pathway in mammals. We show here that Ku binds to mammalian telomeric DNA ends in vitro and that G-quartet conformations are unable to prevent Ku from binding with high affinity to the DNA. Our results indicate that the DNA binding characteristics of Ku are consistent with its direct interaction with telomeric DNA in mammalian cells and its proposed role as a telomere end factor.

Idiotype vaccination in human myeloma: generation of tumor-specific immune responses after high-dose chemotherapy

Igs contain unique portions, collectively termed idiotypes (Id), that can be recognized by the immune system. Id expressed by tumor cells in B-cell malignancies can be regarded as tumor-specific antigens and a target for vaccine immunotherapy. We have started a vaccination trial in multiple myeloma (MM) using Id-specific proteins conjugated to keyhole limpet hemocyanin (KLH) as immunogens and low doses of subcutaneous granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin-2 (IL-2) as immunoadjuvants. Twelve patients who had previously been treated with high-dose chemotherapy followed by peripheral blood progenitor cell (PBPC) transplantation entered this study from August 1995 to January 1998. All patients were in first remission at the time of vaccination. They received subcutaneous injections of Id vaccines and immunoadjuvants in an outpatient setting. The generation of Id-specific T-cell proliferative responses was documented in 2 patients, whereas a positive Id-specific delayed-type hypersensitivity (DTH) reaction was observed in 8 of the 10 patients studied. DTH specificity was confirmed in 1 patient by investigating the reactivity to synthetic peptides derived from the VDJ sequence of the tumor-specific Ig heavy chain. None of the patients generated soluble immune responses to Id, whereas the generation of soluble and cellular immune responses to KLH was observed in 100% and 80%, respectively. Eleven patients completed the treatment, whereas 1 patient failed to finish owing to progression of disease. Freedom from disease progression (FFDP), measured from the date of first Id/KLH injection to the date of first treatment after vaccination or last follow-up, ranged from 9 to 36 months. These data indicate that the immune competence status of MM patients is still susceptible to specific immunization after high-dose chemotherapy and PBPC transplantation. It remains to be determined whether generation of Id-specific immune responses can reduce the relapse rate of patients with minimal residual disease.

Plasma leptin levels after biliopancreatic diversion: dissociation with body mass index

Human obesity is associated with increased leptin levels, related to body composition and fat mass (FM). Insulin has been suggested to be a regulator of in vivo leptin secretion. To further investigate the relationships between insulin and leptin levels in human obesity, we have studied 10 obese females, aged 26-57 yr [body mass index (BMI), 42.9+/-6.3], successfully treated by biliopancreatic (BPD) diversion, in an early postoperative period (2 months after surgery, post-BPD I; BMI, 37.2+/-7.5) and a late postoperative period (16-24 months after surgery; BMI, 27.6+/-3.96). Fourteen normal female subjects (18-59 yr; BMI, 27.9+/-1.4 kg/m2) were studied as controls. In pre-BPD obese subjects, leptin levels were higher than those in controls (60.5+/-18.8 vs. 28.7+/-4.8 ng/mL; P<0.001). BMI and insulin levels were also significantly greater (P<0.0001 and P<0.03, respectively). After surgery, the three parameters considered significantly decreased (P = 0.0007 for BMI, P<0.0001 for leptin, and P = 0.038 for insulin, using Friedman's test for repeated data). Concerning the correlation between leptin and FM in our patients, control subjects and pre-BPD subjects confirmed the correlation found in the general population (r = 0.78; P<0.01). On the contrary, post-BPD patients at 2 months lay outside the general correlation between FM and leptin; in fact, patients with low leptin levels still had a high FM. Moreover, in the post-BPD patients there was no longer a significant correlation between FM and leptin. Concerning the correlation between insulin and leptin levels, a significant correlation was present in control subjects and pre-BPD patients (r = 0.46; P<0.05). Using correlation analysis for repeated measures in surgically treated obese patients, a significant correlation within the subjects was present (r = 0.91; P<0.0001). After operation, BMI and leptin levels had a different pattern of decrease; leptin decreased rapidly, without correlation with BMI, indicating that body composition is not the only factor regulating leptin levels. The consistent correlation with insulin levels suggests an important interaction between these two hormones in post-BPD obese subjects.

[NMR in the diagnosis and treatment of neurologic lesions in decompression sickness]

The case of a decompression sickness in woman, diving to 26 meter depth is reported. The patient was helped by instructor's computer (error!) and she presented risk factors for embolic disease (obesity, smoke, estroprogestinic therapy). She presented with many symptoms of decompression sickness during immersion and during re-ascent (headache, vertigoes and paresthesias). She was not treated on the place of incident, but only 36 hours later at our center of hyperbaric medicine. Her Magnetic Resonance imaging showed hyperintensity lesions of white matter.

Hypothalamic derangement in traumatized patients: growth hormone (GH) and prolactin response to thyrotrophin-releasing hormone and GH-releasing hormone

OBJECTIVE

To study the impact of severe head injury on both basal pituitary hormone secretion and the response to exogenous synthetic hypothalamic releasing factors (TRH and GHRH) in order to evaluate sequential changes in the central control of hypophyseal secretion in the days following head injury.

DESIGN

Prospective clinical study

PATIENTS

21 comatose male patients with head injuries, each intubated and ventilated, intensively monitored and having no previous endocrine problems.

MEASUREMENTS

AND RESULTS The GH and PRL responses to TRH (200 microg iv), and the GH and PRL responses to GHRH (50 microg iv) were evaluated, respectively, on the days 1 and 16 and on days 2, 7and 15 after admission. Daily blood samples were also collected for GH, PRL, TSH, T3 and T4 evaluation. In the basal samples taken on days 2, 7 and 15, IGF-I and cortisol were also determined. Nitrogen balance was assessed daily. On the day 1, TRH increased GH levels from 9.8 +/- 2.2 to 22.4 +/- 6.5 mU/l but failed to induce GH release on day 16. The PRL response to TRH was normal. The GH peak response to GHRH was normal on the day 2 (35.7 +/- 13.9 mU/l), but was increased on days 7 and 15 (68.3 +/- 10.7 mU/l on day 7; 73.8 +/- 9.2 mU/l on day 15, P < 0.01 vs. day 2). We found a significant PRL response to GHRH during the whole period of observation. In the daily evaluation, nitrogen balance was negative in all patients from the day 1 to 5. On average, all patients reached a positive nitrogen balance on the day 8. Compared to the day 2, a statistical increase in IGF-I concentration was observed on days 7 and 15.

CONCLUSIONS

The evaluation of pituitary dynamics in the acute phase of a severe injury demonstrates an alteration of GH and PRL secretion, which correlate with the aminergic and/or peptidergic derangements. Taken together, our data suggest augmented tone of both GHRH and somatostatin in the very acute phase, while an imbalance of releasing factors is hypothesized in the following days. The metabolic consequences of this neuroendocrine pattern could be advantageous in the rapid recovery from the cascade of events produced by the trauma, as documented by the increase in IGF-1 levels and the positive nitrogen balance.

A pilot study of iron depletion as adjuvant therapy in chronic hepatitis C patients not responding to interferon

The aim of this study was to assess the efficacy of iron depletion obtained by phlebotomy to enhance interferon response in 11 patients who had failed to respond to a standard 3-month interferon treatment. Despite a significant effect on serum aminotransferase levels, there was no effect on viremia, and iron depletion was unable to trigger interferon response.

Spectral analysis of heart rate variability in elderly non-dipper hypertensive patients

To assess by autoregressive model the frequency domain heart rate variability (HRV) during clinostatism and after passive orthostatic load (head-up tilt), 81 hypertensive and normotensive subjects (42 men and 39 women) were subdivided into four groups: 20 adult normotensive subjects (Group 1); 21 elderly normotensive subjects (Group 2); 20 elderly hypertensive subjects with nocturnal blood pressure (BP) falls (Group 3); and 20 elderly hypertensive subjects without nocturnal BP falls (Group 4). They were chosen to assess the influence of aging and arterial hypertension on sympathetic-parasympathetic balance. The age-related decrease observed in nearly all HRV spectral frequency components (normalised units [NUs], high frequency [HF] and low frequency [LF]) was reported in elderly patients in rest conditions. LF indexes resulted in decreases in Group 3 and these data seemed to be emphasised in Group 4. After passive tilt, spectral data were recorded as follows: 25.3+/-1.8 vs 17.8+/-2.2 HF, Group 2 vs Group 1, P<0.001; 72.5+/-0.8 vs 75.6+/-1.8 LF, P< 0.001, Group 2 vs Group 1. Both sympathetic and parasympathetic indexes were lower in Group 3 (44.6+/-1.1 vs 72.5+/-0.8 LF, P< 0.001, Group 3 vs Group 2; 9.9+/-1.8 vs 25.3+/-1.8 HF, P < 0.001, Group 3 vs Group 2) and data became clearer in Group 4 (8.5 2.1 vs 9.9+/-1.8 HF, P< 0.001; 40.4+/-1.5 vs 44.6+/-1.1 LF, Group 4 vs Group 3). The established influence of aging on autonomic nervous system activity appears to be increased by arterial hypertension due to worsening of the sympathetic-parasympathetic response to standardised stimulation. The loss of nocturnal BP declines in arterial hypertension was found to occur in association with a decrease in autonomic nervous system activity.

Semirigid fixation of the mandible in bimaxillary orthognathic surgery: stability after 18 months

The stability of osteosynthesis with the use of semirigid mandibular fixation was evaluated in 15 patients who underwent bimaxillary procedures for correction of Class III malocclusion. All patients received rigid fixation (4 miniplates and screws) in the maxilla. Cephalometric evaluation was performed before the operation, immediately after the operation, and at least 18 months after the operation. At the 18-month follow-up, a mean mandibular relapse of 2.2 mm, associated with an additional advancement of the maxilla of 0.27 mm, was observed. The dental relationship was substantially correct. Stability of mandibular fragments in this sample of patients depended on the stability of the maxilla. In addition, neither clinical damage to the temporomandibular joint nor lesions to the neurovascular bundle were detected.

Mammalian telomeres end in a large duplex loop

Mammalian telomeres contain a duplex array of telomeric repeats bound to the telomeric repeat-binding factors TRF1 and TRF2. Inhibition of TRF2 results in immediate deprotection of chromosome ends, manifested by loss of the telomeric 3' overhang, activation of p53, and end-to-end chromosome fusions. Electron microscopy reported here demonstrated that TRF2 can remodel linear telomeric DNA into large duplex loops (t loops) in vitro. Electron microscopy analysis of psoralen cross-linked telomeric DNA purified from human and mouse cells revealed abundant large t loops with a size distribution consistent with their telomeric origin. Binding of TRF1 and single strand binding protein suggested that t loops are formed by invasion of the 3' telomeric overhang into the duplex telomeric repeat array. T loops may provide a general mechanism for the protection and replication of telomeres.

Improvement of pulmonary function after lobectomy for non-small cell lung cancer in emphysematous patients

OBJECTIVE

Pulmonary emphysema is frequently associated with lung cancer and, because of the impaired pulmonary function involved, it may contraindicate surgical treatment. However, improvement of pulmonary function has been observed after surgical resection in patients with advanced emphysema. The aim of this study was to evaluate whether pulmonary emphysema, as assessed by pulmonary function tests and radiological evaluation, can influence postoperative respiratory function after lobectomy for non-small cell lung cancer (NSCLC).

METHODS

Respiratory function was evaluated before and after lobectomy for NSCLC. Radiological evaluation of emphysema was performed on chest X-ray and CT scan. Patients that had undergone chemo- or radiotherapy or had segmental or lobar atelectasis were excluded from the study.

RESULTS

Thirty-five patients entered the study. A decrease in static lung volumes was observed after surgery. Total lung capacity (TLC) decreased from 6.58+/-0.92 to 5.46+/-0.77 l; functional residual capacity (FRC) from 3.70+/-0.88 to 2.96+/-0.73 1 and residual volume (RV) from 2.93+/-0.78 to 2.2+/-0.53 l. However, in a subgroup of 10 patients (Group 1), dynamic volumes after surgery were unchanged or slightly increased (forced vital capacity (FVC) from 3.23+/-0.65 to 3.3+/-0.68 l; forced expiratory volume in 1 s (FEV1) from 2.14+/-0.51 to 2.25+/-0.54 l), and airway resistances (sRaw) decreased from 15.58+/-5.18 to 11.42+/-5.25 cm H2O/s. Preoperative data showed that these patients had a greater obstruction, with FEV1 changing from 69+/-12.42 to 72.70+/-13.72% of predicted, as compared with a change from 87+/-12.7 to 72.08+/-13.10% in the other group of 25 patients (Group 2). Correlation analysis reached statistical significance between FEV1% variation (deltaFEV1%) and preoperative FEV1 and FVC% (r = -0.49, P = 0.002 and r = -0.5, P = 0.001, respectively) and between delta (FEV1)% and radiological scores for 3-level CT (r = 0.39, P = 0.04) and the sum of chest X-ray, single and 3-level CT scores (r = 0.49, P = 0.01).

CONCLUSIONS

Pulmonary function may remain unchanged or even increase after lobectomy in patients with a pronounced emphysematous component of airway obstruction. The identification of preoperative parameters that identify this group of patients could extend the indications for the treatment of lung cancer in patients with pulmonary emphysema.

Evaluation of a putative major susceptibility locus for juvenile myoclonic epilepsy on chromosome 15q14

Juvenile myoclonic epilepsy (JME) is a genetically determined common subtype of idiopathic generalized epilepsy (IGE). Significant evidence for linkage has been reported for a susceptibility locus for JME in the chromosomal region 15q14 that harbors the gene encoding the alpha7 subunit of the neuronal nicotinic acetylcholine receptor (CHRNA7). The present study was designed to test the earlier linkage finding and to explore whether this susceptibility locus is involved in the epileptogenesis of a broader spectrum of IGE syndromes. Multipoint parametric and nonparametric linkage analyses with seven microsatellite polymorphisms encompassing the region of the CHRNA7 gene were performed using two diagnostic schemes of JME-related traits in two groups of multiplex families ascertained through probands with either JME (n = 27) or idiopathic absence epilepsy (n = 30). The present linkage study failed to replicate evidence for a major susceptibility locus for JME in the region encompassing the CHRNA7 gene. In addition, we found no hint in favor of linkage to 15q14 under the broad diagnostic scheme in any of the sets of families. If genetic variation in this region confers susceptibility to JME, then its effect size might be too small or its occurrence too rare to be detected in the investigated families.