Classification of BRCA1 missense variants of unknown clinical significance.

BACKGROUND: BRCA1 is a tumour suppressor with pleiotropic actions. Germline mutations in BRCA1 are responsible for a large proportion of breast-ovarian cancer families. Several missense variants have been identified throughout the gene but because of lack of information about their impact on the function of BRCA1, predictive testing is not always informative. Classification of missense variants into deleterious/high risk or neutral/low clinical significance is essential to identify individuals at risk. OBJECTIVE: To investigate a panel of missense variants. METHODS AND RESULTS: The panel was investigated in a comprehensive framework that included (1) a functional assay based on transcription activation; (2) segregation analysis and a method of using incomplete pedigree data to calculate the odds of causality; (3) a method based on interspecific sequence variation. It was shown that the transcriptional activation assay could be used as a test to characterise mutations in the carboxy-terminus region of BRCA1 encompassing residues 1396-1863. Thirteen missense variants (H1402Y, L1407P, H1421Y, S1512I, M1628T, M1628V, T1685I, G1706A, T1720A, A1752P, G1788V, V1809F, and W1837R) were specifically investigated. CONCLUSIONS: While individual classification schemes for BRCA1 alleles still present limitations, a combination of several methods provides a more powerful way of identifying variants that are causally linked to a high risk of breast and ovarian cancer. The framework presented here brings these variants nearer to clinical applicability.

Sutural cataract, retinitis pigmentosa, microcephaly and psychomotor retardation. A new autosomal recessive disorder?

We report four children (three sibs and one sporadic case) with congenital sutural cataract (opacity of the sutures of the crystalline lens), retinitis pigmentosa (leading to diminished visual acuity), microcephaly, and moderate to severe psychomotor retardation. The three sibs (two F and one M) were born to healthy, consanguineous Moroccan parents; the sporadic case is an 11-year-old Dutch girl who presented at the age of nine months with a small head circumference (third percentile) and sutural cataract. Psychomotor development was retarded in all cases, retinitis pigmentosa became evident during middle or late childhood. Congenital cataract has been described in association with a large number of various congenital abnormalities, such as renal, nervous system, skeletal, dermal and ocular (including retinal) defects. A computer-assisted literature search has not revealed similar cases to those presented here. The cases described here appear to have a previously undescribed combination of ophthalmological and cerebral abnormalities. The inheritance of the condition appears to be autosomal recessive as a brother and two sisters (offspring of normal consanguineous parents) are affected. The differential diagnosis is discussed.

Unusual association of congenital malformations: craniosynostosis, heart defect, abnormal intestinal innervation and urogenital abnormalities.

Monozygotic male twins and an unrelated boy are described who have an unusual association of malformations, i.e. craniosynostosis of the sagittal suture, a cardiac malformation, urogenital anomalies, intestinal malformations and a single umbilical artery. The twins are discordant for these features, except for Hirschsprung disease. No similar cases could be traced in literature. The possible genetic background is discussed.

[Post-asphyctic encephalopathy of the neonate following administration of nalbuphine during childbirth]. / Postasfyctische encefalopathie van de pasgeborene na toediening van nalbufine tijdens de baring.

After an intramuscular injection of nalbuphine during parturition a foetal bradycardia of 30-40 beats/minute developed, which normalised after an intravenous maternal injection of naloxone. Because the cardiotocography did not show variability after the event, a caesarean section was performed. Six months later the child still had a severe neurological disorder which was attributed to intrauterine asphyxia. Several authors published reports in which no relevant clinical problems were described after nalbuphine given during labour. Recently, however, four children have been described with bradycardia and respiratory depression after maternal intravenous and/or intramuscular injection of nalbuphine. Apparently, the use of nalbuphine during labour can cause foetal bradycardia, both after intravenous and after intramuscular administration. Great reserve is advised regarding use of nalbuphine for this indication. The antidote naloxone should be within reach.

Counselling in multiple endocrine neoplasia syndromes: from individual experience to general guidelines.

Counselling of patients and closely related family members has to take a central place in management of hereditary diseases, like multiple endocrine neoplasia (MEN) syndromes including von Hippel-Lindau (VHL) disease. In the strategy of health care, preventive medicine such as periodic clinical examination of families at-risk needs a high priority, because in general it is assumed that continuity in attendance is cost-effective. Counselling has to be based on individual medical experience of the doctor, adjusted to common guidelines and the findings in the family. Information leaflets, appropriate outpatient departments and an extensive network of specialists will facilitate continuity in care. Flow diagrams involving practical guidelines for diagnosis, treatment and follow up need to be applicable and after adjustment, should be accepted generally. Specially trained paramedics for counselling are required as a network that will guarantee periodic clinical examination and secure optimal prevention. Such paramedics will coordinate nationwide multidisciplinary guidance, and organize preventive and emergency cure for these patients. They will be supervised by expert clinicians in the field, and collaborate with specialists for social and psychological issues, patient organizations and clinical genetic centres. All of these professionals are responsible together for providing patients with up to date clinical information (via newsletters, Internet, etc.). Recently, in the Netherlands, a project was initiated to guarantee continuity in care and study the delivery of care. In order to realize this plan, funding has to be provided in the current research programme. In a future system support has to be obtained on a continuous base, preferably by the government and health care insurers and supervised by the national institute for health care.

On the many faces of Leber hereditary optic neuropathy.

Leber hereditary optic neuropathy (LHON) is a maternally inherited disorder, associated with mutations in the mitochondrial DNA, which is notorious for its aspecific presentations. Two pedigrees are described with cases that are atypical for LHON with respect to sex, age of onset, interval between the eyes becoming affected, course of the disease, concomitant disorders, additional test results, final visual acuity, and/or results of mtDNA analysis. Moreover, the pedigrees themselves did not suggest maternal inheritance. We analysed the diagnostic and clinical genetic difficulties related to the atypical aspects of these pedigrees. We conclude that mtDNA analysis is justified in every case of optic nerve atrophy with no clear cause. Identification of one of the three LHON specifically associated mtDNA mutations is essential to confirm the diagnosis.