Developmental delay of infants and young children with and without fetal alcohol spectrum disorder in the Northern Cape Province, South Africa

OBJECTIVE

To describe the extent and nature of developmental delay at different stages in childhood in a community in South Africa, with a known high rate of Fetal Alcohol Spectrum Disorder (FASD).

METHOD

cohort of infants, clinically examined for FASD at two time periods, 7-12 months (N= 392; 45 FASD) and 17-21 months of age (N = 83, 35 FASD) were assessed using the Griffiths Mental Developmental Scales (GMDS).

RESULTS

Infants and children with FASD perform worse than their Non-FASD counterparts over all scales and total developmental quotients. Mean quotients for both groups decline between assessments across subscales with a particularly marked decline in the hearing and language scale at Time 2 (scores dropping from 110.6 to 83.1 in the Non-FASD group and 106.3 to 72.7 in the FASD group; P = 0.004). By early childhood the developmental gap between the groups widens with low maternal education, maternal depression, high parity and previous loss of sibling/s influencing development during early childhood.

CONCLUSION

The FASD group show more evidence of developmental delay over both time points compared to their Non-FASD counterparts. Demographic and socio-economic factors further impact early childhood. These findings are important in setting up primary level psycho-educational and national prevention programmes especially in periurban communities with a focus on early childhood development and FASD.

Comparative cost and performance of light-emitting diode microscopy in HIV-tuberculosis-co-infected patients

Light-emitting diode (LED) microscopy has recently been endorsed by the World Health Organization (WHO). However, it is unclear whether LED is as accurate and cost-effective as Ziehl-Neelsen (ZN) microscopy or mercury vapour fluorescence microscopy (MVFM) in tuberculosis (TB)-HIV-co-infected subjects. Direct and concentrated sputum smears from TB suspects were evaluated using combinations of LED microscopy, ZN microscopy and MVFM. Median reading time per slide was recorded and a cost analysis performed. Mycobacterial culture served as the reference standard. 647 sputum samples were obtained from 354 patients (88 (29.8%) were HIV-infected and 161 (26%) were culture-positive for Mycobacterium tuberculosis). Although overall sensitivity of LED compared with ZN microscopy or MVFM was similar, sensitivity of all three modalities was lower in HIV-infected patients. In the HIV-infected group, the sensitivity of LED microscopy was higher than ZN microscopy using samples that were not concentrated (46 versus 39%; p = 0.25), and better than MVFM using concentrated samples (56 versus 44; p = 0.5). A similar trend was seen in the CD4 count <200 cells · mL(-1) subgroup. Median (interquartile range) reading time was quicker with LED compared with ZN microscopy (1.8 (1.7-1.9) versus 2.5 (2.2-2.7) min; p ≤ 0.001). Average cost per slide read was less for LED microscopy (US$1.63) compared with ZN microscopy (US$2.10). Among HIV-TB-co-infected patients, LED microscopy was cheaper and performed as well as ZN microscopy or MVFM independent of the staining (ZN or auramine O) or processing methods used.

A stereo-photogrammetric method to measure the facial dysmorphology of children in the diagnosis of fetal alcohol syndrome

In diagnosing a child with fetal alcohol syndrome (FAS), anthropometric measurements of the face are conventionally performed by highly trained dysmorphologists using a hand-held ruler. This renders the screening of large populations of children for the facial features characteristic of FAS very time-consuming and costly. This study proposes a new, cost-effective, and non-intrusive method to measure in three dimensions the facial dysmorphology of children using stereo-photogrammetry. The face of each child is photographed in a control frame simultaneously by a pair of high-resolution digital cameras mounted 1.04 m from the child and 0.26 m apart. Software has been developed to calibrate the images and to compute the three-dimensional object-space coordinates of any point on the face from a measurement of the point on each of the images. The palpebral fissure lengths, inner canthal-, and interpupillary distances of 44 subjects were measured in this manner independently by two investigators and compared with measurements obtained by clinical specialists in the conventional manner. There was found to be no statistically significant difference between palpebral fissure lengths determined using the two techniques (paired Student's t-test p-values are 0.29 and 0.18, respectively). It has also been demonstrated that facial measurements can be performed with greater consistency from a pair of stereo photographs than direct measurements from live subjects.

Sorting nexin 3 (SNX3) is disrupted in a patient with a translocation t(6;13)(q21;q12) and microcephaly, microphthalmia, ectrodactyly, prognathism (MMEP) phenotype

A patient with microcephaly, microphthalmia, ectrodactyly, and prognathism (MMEP) and mental retardation was previously reported to carry a de novo reciprocal t(6;13)(q21;q12) translocation. In an attempt to identify the presumed causative gene, we mapped the translocation breakpoints using fluorescence in situ hybridisation (FISH). Two overlapping genomic clones crossed the breakpoint on the der(6) chromosome, locating the breakpoint region between D6S1594 and D6S1250. Southern blot analysis allowed us to determine that the sorting nexin 3 gene (SNX3) was disrupted. Using Inverse PCR, we were able to amplify and sequence the der(6) breakpoint region, which exhibited homology to a BAC clone that contained marker D13S250. This clone allowed us to amplify and sequence the der(13) breakpoint region and to determine that no additional rearrangement was present at either breakpoint, nor was another gene disrupted on chromosome 13. Therefore, the translocation was balanced and SNX3 is probably the candidate gene for MMEP in the patient. However, mutation screening by dHPLC and Southern blot analysis of another sporadic case with MMEP failed to detect any point mutations or deletions in the SNX3 coding sequence. Considering the possibility of positional effect, another candidate gene in the vicinity of the der(6) chromosome breakpoint may be responsible for MMEP in the original patient or, just as likely, the MMEP phenotype in the two patients results from genetic heterogeneity.

Functional relevance of human adh polymorphism

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were C. J. Peter Eriksson and Tatsushige Fukunaga. The presentations were (1) 4-Methylpyrazole as a tool in the investigation of the role of ADH in the actions of alcohol in humans, by Taisto Sarkola and C. J. Peter Eriksson; (2) ADH2 polymorphism and flushing in Asian populations, by Wei J. Chen, C. C. Chen, J. M. Ju, and Andrew T. A. Cheng; (3) Role of ADH3 genotypes in the acute effects of alcohol in a Finnish population, by Hidetaka Yamamoto, Kathrin Kohlenberg-Müller, and C. J. Peter Eriksson; (4) Clinical characteristics and disease course of alcoholics with different ADH2 genotypes, by Mitsuru Kimura, Masanobu Murayama, Sachio Matsushita, Haruo Kashima, and Susumu Higuchi; (5) ADH2 polymorphism, alcohol drinking, and birth defects, by Lucinda Carr, D. Viljoen, L. Brooke, T. Stewart, T. Foroud, J. Su, and Ting-Kai Li; and (6) ADH genotypes and alcohol use in Europeans, by John B. Whitfield.

Patterns of cognitive-motor development in children with fetal alcohol syndrome from a community in South Africa

BACKGROUND

Even though fetal alcohol syndrome (FAS) has been reported in nonwestern nations, there is a paucity of information on neurodevelopment in the affected children from those nations. This article reports on a study of cognitive-motor development in a group of children with FAS from a community in the Western Cape Province in South Africa.

METHODS

Thirty-four children with FAS and 34 controls from grade 1 (school entry level) classes participated. The two groups comprised Afrikaans-speaking children of mixed ancestry (South African Colored) and were matched for age, sex, and family income. The Griffiths Mental Development Scales were used to assess cognitive motor development of the participants.

RESULTS

A multivariate analysis of covariance was performed to test the group effect on the combined Griffiths subscales adjusting for maternal education. The results showed a significant group effect. Follow-up analyses revealed that a combination of four subscales (Speech and Hearing, Performance, Practical Reasoning, and Eye and Hand Coordination) primarily contributed to the overall effect. Although there was a marginal effect on the Personal-Social subscale, no significant effect on the Locomotor (gross motor) subscale was found.

CONCLUSIONS

The results showed that the FAS group was markedly deficient only in higher-order cognitive-motor competencies.

Mutations of the gene encoding the transmembrane transporter protein ABC-C6 cause pseudoxanthoma elasticum

We recently published the precise chromosomal localization on chromosome 16p13.1 of the genetic defect underlying pseudoxanthoma elasticum (PXE), an inherited disorder characterized by progressive calcification of elastic fibers in skin, eye, and the cardiovascular system. Here we report the identification of mutations in the gene encoding the transmembrane transporter protein, ABC-C6 (also known as MRP-6), one of the four genes located in the region of linkage, as cause of the disease. Sequence analysis in four independent consanguineous families from Switzerland, Mexico, and South Africa and in one non-consanguineous family from the United States demonstrated several different mis-sense mutations to cosegregate with the disease phenotype. These findings are consistent with the conclusion that PXE is a recessive disorder that displays allelic heterogeneity, which may explain the considerable phenotypic variance characteristic of the disorder.

Epidemiology of fetal alcohol syndrome in a South African community in the Western Cape Province

OBJECTIVES

This study determined the characteristics of fetal alcohol syndrome in a South African community, and methodology was designed for the multidisciplinary study of fetal alcohol syndrome in developing societies.

METHODS

An active case ascertainment, 2-tier methodology was used among 992 first-grade pupils. A case-control design, using measures of growth, development, dysmorphology, and maternal risk, delineated characteristics of children with fetal alcohol syndrome.

RESULTS

A high rate of fetal alcohol syndrome was found in the schools--40.5 to 46.4 per 1000 children aged 5 to 9 years--and age-specific community rates (ages 6-7) were 39.2 to 42.9. These rates are 18 to 141 times greater than in the United States. Rural residents had significantly more fetal alcohol syndrome. After control for ethnic variation, children with fetal alcohol syndrome had traits similar to those elsewhere: poor growth and development, congruent dysmorphology, and lower intellectual functioning.

CONCLUSIONS

This study documented the highest fetal alcohol syndrome rate to date in an overall community population. Fetal alcohol syndrome initiatives that incorporate innovative sampling and active case ascertainment methods can be used to obtain timely and accurate data among developing populations.

A 500-kb region on chromosome 16p13.1 contains the pseudoxanthoma elasticum locus: high-resolution mapping and genomic structure

We have recently mapped the genetic defect underlying pseudoxanthoma elasticum (PXE), an inherited disorder characterized by progressive calcification of elastic fibers in skin, eye, and cardiovascular system, to chromosome 16p 13.1. Here we report further data on the fine-mapping and genomic structure of this locus. Haplotype analysis of informative PXE families narrowed the locus to an interval of less than 500 kb located between markers D16B9621 and D16S764. Three overlapping YAC clones were found to cover this region through YAC-STS content mapping. An overlapping BAC contig was then constructed to cover this interval and the surrounding region. About 80% of this chromosomal region has been fully sequenced using the BAC shotgun technique. Gene content and sequence analysis predicted four genes (MRP1, MRP6, PM5, and a novel transcript) and two pseudogenes (ARA and PKDI) within this interval. By screening a somatic cell hybrid panel we were able to precision-map the breakpoint of Cy185 and the starting point of a chromosomal duplication within 20 kb of BAC A962B4. The present data further refine the localization of PXE, provide additional physical cloning resources, and will aid in the eventual identification of the genetic defect causing PXE.

Alcohol consumption by pregnant women in the Western Cape

OBJECTIVE

To assess alcohol use by pregnant women in three underprivileged areas of the Western Cape.

DESIGN

Data were collected from subjects, selected in a randomised manner, during a single, structured interview.

SUBJECTS AND SETTING

Interviews were conducted among pregnant women voluntarily attending selected antenatal clinics in the George/Oudtshoorn, Vredenburg/Saldanha, and Cape Metropole areas of the Western Cape.

OUTCOME MEASURES

On completion of the interview, women at risk were counselled with regard to the dangers of prenatal alcohol exposure to the fetus.

RESULTS

42.8% of the women in the sample admitted to varying degrees of alcohol ingestion during the current pregnancy. The reported alcohol intake of over 55% of these women, i.e. 23.7% of the sample, was sufficient to place their unborn children at high risk for the fetal alcohol syndrome (FAS). These heavy drinkers followed a pattern of binge drinking over weekends and showed a marked preference for beer. Combined alcohol and tobacco use occurred in 29.6% of the sample. Only one subject admitted to using marijuana.

CONCLUSION

The data in this study confirm that a high rate of alcohol and tobacco use prevails among pregnant women in poorer communities of the Western Cape. Extrapolating from experience, as many as 9.5% of the sample may produce children with FAS.

Mseleni and Handigodu familial osteoarthropathies: syndromic identity?

Mseleni joint disease (MJD) and Handigodu joint disease (HJD) are familial skeletal disorders that affect several hundred persons in northern Zululand, South Africa and in the Shimoga district of southern India, respectively. Severe precocious, progressive degenerative osteoarthropathy, which occurs in both conditions, causes marked physical handicap by adulthood. The clinical and radiological manifestations of MJD and HJD are very similar and it is possible that they represent the same entity. HJD appears to be inherited as an autosomal dominant trait, while MJD clusters in families without a definite Mendelian pattern. It is possible that an environmental factor is active in the pathogenesis of both disorders and comparative investigations would be fruitful. The predominance of severe degenerative osteoarthropathy in both disorders may have important implications for the elucidation of the pathogenesis of the common conventional forms of osteoarthropathy.

Familial streptomycin ototoxicity in a South African family: a mitochondrial disorder

The vestibular and ototoxic effects of the aminoglycoside antibiotics (streptomycin, gentamycin, kanamycin, tobramycin, neomycin) are well known; streptomycin, in particular, has been found to cause irreversible, profound, high frequency sensorineural deafness in hypersensitive persons. Aminoglycoside ototoxicity occurs both sporadically and within families and has been associated with a mitochondrial DNA (mtDNA) 1555A to G point mutation in the 12S ribosomal RNA gene. We report on the molecular analysis of a South African family with streptomycin induced sensorineural deafness in which we have found transmission of this same predisposing mutation. It is now possible to identify people who are at risk of hearing loss if treated with aminoglycosides in the future and to counsel them accordingly. In view of the fact that aminoglycoside antibiotics remain in widespread use for the treatment of infections, in particular for tuberculosis, which is currently of epidemic proportions in South Africa, this finding has important implications for the family concerned. In addition, other South African families may potentially be at risk if they carry the same mutation.

Twenty-year birth prevalence of Down syndrome in Cape Town, South Africa

The 20-year birth prevalence of Down syndrome in Cape Town, South Africa, was determined. All cases delivered to mothers in Cape Town, plus terminations following prenatal diagnosis, between 1 January 1974 and 31 December 1993 were ascertained. There were 784 Down syndrome pregnancies, of which 95% were trisomies. The 32 terminations comprised 18.3% of the white, 5.8% of the coloured (mixed race) and 1.4% of the black cases. The overall prevalence rate was 1.49 per 1000 (white 1.88, coloured 1.54 and black 1.29 per 1000). Analysis for linear trends showed a significant decline in rates for the total population and for whites, a downward trend for coloureds, but no decline for blacks. Over the last 5-year period the prevalence rates in all three population groups were 1.3 per 1000. An increasing risk with advancing maternal age was confirmed, but no maternal age-specific differences in rates by race were demonstrated.

Mseleni joint disease--a molecular genetic approach to defining the aetiology

Mseleni joint disease (MJD) is an unusual form of progressive and widespread degenerative osteoarthropathy that has been identified in several hundred people in the remote Mseleni region of northern Zululand. Affected individuals experience articular discomfort in childhood and may be seriously handicapped as adults, often requiring prosthetic hip joint replacement. Although the condition clusters in families, there is no evidence of Mendelian inheritance and assessment of affected kindreds has not shown any evidence of genomic imprinting. To date our molecular work-up has entailed the study of 47 affected individuals from MJD kindreds to investigate familial predisposition based on the inheritance of a subset of markers and/or genes on the human genome, particularly those associated with the cartilage matrix. In addition, we have collected blood specimens form 111 unaffected but unrelated individuals from the same population group in order to determine whether any relationship exists between genetic components of the human leucocyte antigen (HLA) system and the MJD phenotype. Our investigations show the following: (i) there is no association between MJD and the HLA system which has previously been associated with non-Mendelian genetic conditions; (ii) COL2A1, which has been implicated in some forms of spondylo-epiphyseal dysplasia, may be involved in at least a subset of MJD patients; and (iii) type VI collagen is overabundant in degenerated hip joint cartilage.

Patient attitudes to prenatal screening and termination of pregnancy at Groote Schuur Hospital: a two year prospective study

A prospective 2-year study involving a questionnaire administered by a Genetic Counsellor was carried out to ascertain patient attitudes to prenatal screening and termination of pregnancy (TOP) at Groote Schuur Hospital. Women were questioned regarding their religious affiliation, education, ethnic group, reason for referral and age. Following ultrasonography, non-directive counselling was given regarding amniocentesis and TOP. Four hundred and sixty six women were investigated of whom 74% were of mixed ancestry, 14% Black and 12% White. Three hundred and sixteen persons were offered amniocentesis (67.8%). Muslim women accepted less frequently (66%) than other religious affiliations (79.7%) (p = 0.025). Overall amniocentesis acceptance was 75.9%. TOP was performed in 45 pregnancies (9.7%). Muslim women accepted TOP 1.33 times (C.I. 0.32-5.6) more frequently than those of other religious persuasions. Overall TOP acceptance rate was 76.3%. The mixed ethnic population of pregnant women seen at Groote Schuur Hospital readily accept prenatal screening and TOP following non-directive genetic counselling. The introduction of prenatal screening programmes for the prevention of severe congenital defects in this population would be successful and cost-effective.

Localization of the Schwartz-Jampel syndrome (SJS) locus to chromosome 1p34-p36.1 by homozygosity mapping

Schwartz-Jampel syndrome (SJS, MIM 255800), also known as chondrodystrophic myotonia, is a rare autosomal recessive disorder characterized by generalized myotonia, skeletal abnormalities and facial dysmorphism. Using homozygosity mapping, we localized the SJS locus to chromosome 1p34-p36.1 in a 8 cM interval flanked by markers D1S199 and D1S234. Families of different ethnic backgrounds (Tunisia and South Africa) showed genetic linkage to the same locus. Moreover, one Algerian family also demonstrated evidence of genetic linkage to 1p34-p36.1. Taken altogether, our results suggest genetic homogeneity, at least in the group of families analyzed.

A case of lateral facial cleft, cleft lip and palate, anophthalmia, microtia, clavicular agenesis and asternia

We present a female infant with a complex pattern of congenital malformations including a lateral facial cleft, cleft lip and palate, anophthalmia, microtia, clavicular agenesis and asternia. A differential diagnosis is proposed and discussed.

Aplasia cutis congenita with epibulbar dermoids: further evidence for syndromic identity of the ocular ectodermal syndrome

We have investigated 2 young South African girls with aplasia cutis congenita, epibulbar dermoids, and strabismus. This unique association of anomalies was first documented in two unrelated boys by Toriello et al. [1993: Am. J. Med. Genet. 45:764-766]. Our clinical and histological findings are markedly similar, and we think this to be the second report of individuals with this rare syndrome.

Congenital contractural arachnodactyly (Beals syndrome)

Congenital contractural arachnodactyly (CCA) is an autosomal dominant disorder akin to, but usually less severe than, Marfan syndrome. The clinical features are marfanoid habitus, arachnodactyly, crumpled ears, camptodactyly of the fingers and adducted thumbs, mild contractures of the elbows, knees, and hips, and mild muscle hypoplasia especially of the calf muscles. Many patients have kyphoscoliosis and mitral valve prolapse and, very occasionally, aortic root dilatation and ectopia lentis have been described. Linkage to a gene coding for fibrillin on chromosome 5q23-31 has been shown in several kindreds. The prognosis for a normal lifespan is good and improvement in joint contractures is usual.

Duchenne and Becker muscular dystrophy prevalence in South Africa and molecular findings in 128 persons affected

A genetic service for Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) was initiated in Cape Town in 1987. Of the 143 DMD patients diagnosed during the period 1987-1992, 66 had a familial pattern of inheritance and 77 were apparently sporadic. Twenty BMD patients were identified, of whom 12 had other affected relatives and 8 were sporadic. Overall minimum prevalence rates of 1/100,000 for DMD and 1/755,000 for BMD were calculated. A markedly low DMD prevalence in the indigenous black population (1/250,000) contributed to the overall low DMD prevalence in South Africa when compared with that in the UK (1/40,000). By means of molecular methods, the diagnosis in 42% of the affected DMD males was confirmed by detection of deletions in the dystrophin gene. Deletions were identified in 50% of Indian, white and mixed ancestry patients. In contrast, only 22% of blacks had identifiable deletions. DMD appears to be underrepresented in the black population; the low deletion frequency in this group suggests that unique mutations not detectable by methods used in this study may be more frequent in these patients than in the other populations. The increased DMD frequency in Indians corroborates findings reported from the UK.

Brachydactylous dwarfs of Mseleni

Eight individuals with an unusual dwarfing skeletal dysplasia have been investigated in a remote rural area in Northern Zululand, South Africa. These dwarfed individuals are members of a community numbering some 10,000 persons; approximately 20% have a degenerative arthropathy affecting mainly the major joints of the hips, knees, ankles, and spine. The pathogenesis of the latter disorder, which is known as Mseleni joint disease (MJD), remains obscure. The dwarfed persons have some radiological findings in keeping with MJD, but they are, in addition, of short stature and have marked brachydactyly of their fingers and toes. The pathogenetic relationship between these conditions, if any, is unclear but may have important implications for their causal elucidation.

Osteogenesis imperfecta type III: mutations in the type I collagen structural genes, COL1A1 and COL1A2, are not necessarily responsible

Most forms of osteogenesis imperfecta are caused by dominant mutations in either of the two genes, COL1A1 and COL1A2, that encode the pro alpha 1(I) and pro alpha 2(I) chains of type I collagen, respectively. However, a severe, autosomal recessive form of OI type III with a comparatively high frequency has been recognised in the black populations of southern Africa. We preformed linkage analyses in eight OI type III families using RFLPs associated with the COL1A1 and COL1A2 loci to determine whether mutations in the genes for type I collagen were responsible for this form of OI. Recombination between the OI phenotype and polymorphic markers at both loci was shown in three of the eight families investigated. The combined lod scores for the eight families were -10.6 for COL1A1 and -11.2 for COL1A2. Further, we examined the type I procollagen produced by skin fibroblast cultures derived from 15 affected and 12 unaffected subjects from the above eight families plus one further family. We found no evidence for defects in the synthesis, structure, secretion, or post-translational modification of the chains of type I procollagen produced by any of the family members. These results suggest that mutations within or near the type I collagen structural genes are not responsible for this form of OI.

Developmental anomalies in monozygous twins resembling the human homologue of the mouse mutant disorganization

Human monozygous (Mz) twins are described with a pattern of abnormalities similar to those reported in heterozygous expression of the mouse mutant disorganisation gene (Ds). These include anomalies of the skeletal, gastrointestinal, genito-urinary and central nervous system. Concordance in Mz twins is suggestive of a genetic aetiology and lends further credence to the putative existence of a human homologue for Ds.

Molecular investigation of familial Beckwith-Wiedemann syndrome: a model for paternal imprinting

In familial Beckwith-Wiedemann syndrome (BWS), the mode of inheritance is uncertain and possible patterns include autosomal dominant, multifactorial and autosomal dominant sex-dependent inheritance. Genomic imprinting has recently been invoked to explain the unusual inheritance patterns in several disorders. We have previously reviewed 28 published kindreds of BWS and shown that paternal imprinting is probably responsible for familial BWS. In the present paper, highly informative RFLP markers in the 11p15.5 region have been shown to segregate with the disease gene as an autosomal dominant, but phenotypic manifestations in an offspring are dependent on the sex of the parent contributing the defective gene. In contrast to previous reports in which imprinting of the growth stimulator gene, IGF2, has been invoked as the mechanism explaining sporadic cases of BWS (especially in situations where uniparental disomy and trisomy of the 11p15.5 region has occurred), it is suggested that paternal imprinting of a growth suppressor gene, e.g., H19, may be one of the causes of familial BWS.

Ehlers Danlos syndrome type VIIB. Incomplete cleavage of abnormal type I procollagen by N-proteinase in vitro results in the formation of copolymers of collagen and partially cleaved pNcollagen that are near circular in cross-section

We have shown that a child with Ehlers Danlos syndrome (EDS) type VII has a G to A transition at the first nucleotide of intron 6 in one of her COL1A2 alleles. Half of the cDNA clones prepared from the proband's pro alpha 2(I) mRNA lacked exon 6. The type I procollagen secreted by the proband's dermal fibroblasts in culture was purified, and collagen fibrils were generated in vitro by cleavage of the procollagen with the procollagen N- and C-proteinases. Incubation of the procollagen with N-proteinase resulted in a 1:1 mixture of pCcollagen and uncleaved procollagen. Incubation of this mixture with C-proteinase generated collagen and abnormal pNcollagen (pNcollagen-ex6) that readily copolymerized into fibrils. By electron microscopy these fibrils resembled the hieroglyphic fibrils seen in the N-proteinase-deficient skin of dermatosparactic animals and humans and were distinct from the near circular cross-section fibrils seen in the tissues of individuals with EDS type VII. Further incubation of the hieroglyphic fibrils with N-proteinase resulted in partial cleavage of the pNcollagen-ex6 in which the abnormal pN alpha 2(I) chains remained intact. These fibrils were not hieroglyphic but were near circular in cross-section. Fibrils formed from collagen and pNcollagen-ex6 that had been partially cleaved with elevated amounts of N-proteinase prior to fibril formation were also near circular in cross-section. The results are consistent with a model of collagen fibril formation in which the intact N-propeptides are located exclusively at the surface of the hieroglyphic fibrils. Partial cleavage of the pNcollagen-ex6 by N-proteinase allows the N-propeptides to be incorporated within the body of the fibrils. The model provides an explanation for the morphology and molecular composition of collagen fibrils in the tissues of patients with EDS type VII.

Evidence for paternal imprinting in familial Beckwith-Wiedemann syndrome

A previously unreported family in which seven members in two generations have Beckwith-Wiedemann syndrome (BWS) is documented. Paternal imprinting of the gene responsible for BWS is involved as the mechanism responsible for the aberrant inheritance pattern in this kindred. A review of published reports showed 27 previously published pedigrees with two or more affected subjects with BWS. Paternal imprinting would explain the non-mendelian inheritance of BWS in all but four kindreds. The latter families are examined in more detail and in only one example is the evidence against imprinting totally unexplained.

Schwartz-Jampel syndrome (chondrodystrophic myotonia)

Schwartz-Jampel syndrome is a rare autosomal recessive disorder. Joint contractures, generalised myotonia, skeletal anomalies, and facial dysmorphism are common features; malignant hyperthermia is a potentially lethal complication during anaesthesia.

Hearing impairment and pigmentary disturbance

Hearing impairment is a variable manifestation of several heritable conditions in which pigmentation of the skin or eyes is abnormal. Some of these disorders are well recognized although uncommon, while others are virtually private syndromes. Practical issues concerning the major conditions of this type are reviewed in this article on a basis of a survey of 4452 profoundly deaf children attending special schools in Southern Africa, together with investigations in affected families. The Waardenburg syndrome (WS), which is the most common deafness-depigmentation disorder, was present in 121 (2.7%) of the 4452 deaf scholars. Further studies in 7 multigeneration affected families confirmed phenotypic variability and indicated a need for internationally agreed diagnostic criteria. In 4 Cape Town families of mixed ancestry the WS-I gene was linked to the 2q37 locus, but in another large kindred no linkage could be demonstrated. Nonallelic heterogeneity is possible. There is uncertainty concerning possible interrelationship between WS and piebaldism. The phenotypic consistency of a South African family in which 7 persons in 3 generations had gross piebaldism in the absence of disturbance of hearing or involvement of the eyes and periorbital structures is suggestive that this disorder and WS are separate entities. Molecular investigations indicate that the gene for piebaldism in this kindred is not situated at the WS-I locus 2q37. Deafness and hyperpigmentation are present in neurofibromatosis type II (acoustic neuromata) and the multiple lentigines syndrome, while retinal pigmentation is a feature of the Usher syndrome. This latter entity is apparently much less common in Southern Africa than in other parts of the world.

Beals syndrome: clinical and molecular investigations in a kindred of Indian descent

Eight members of a 3-generation kindred of Indian descent with congenital contractural arachnodactyly (Beals syndrome) have been appraised. Considerable variation was noted in the clinical features of affected persons, and the previously unreported associated finding of clubbing of the fingers and toes was evident in two individuals. The family was investigated using conventional serum and protein markers, and RFLP probes for type I and II collagen. No linkage in affected members could be demonstrated with type I collagen probes.

Dietary manipulation for treating infants with prolonged dehydrating diarrhoea: a comparison of four different formulae

Dietary manipulation is often the first step in the treatment of infants with persistent acute dehydrating diarrhoea. This usually entails elimination of lactose, but other disaccharides or whole protein may be causing the disease. Serial elimination of these takes time and it may be preferable to use a whole protein and disaccharide-free formula as the first feed change. This study assessed the effect on stool weight of a change from cow's milk formula feeds to one of four different formulae in infants with severe diarrhoea persisting after 3 days in hospital. Two feeds were lactose-free soy formulae containing sucrose, one was disaccharide-free soy formula and one a disaccharide-free protein hydrolysate. Regardless of which feed the infants received, diarrhoea resolved in approximately 50% following the change in diet. Comparing those who got better with those who did not, the former were generally better nourished and had an initial lower stool output, but it was impossible to predict on clinical grounds which individual would respond to the removal of cow's milk. The results suggest that elimination of lactose in infants with persistent severe diarrhoea will benefit a significant number in the early stage of the disease. As there is no additional benefit from eliminating sucrose or whole protein at this stage, the cheapest available lactose-free formula should be used initially.

Pseudoxanthoma elasticum: similar autosomal recessive subtype in Belgian and Afrikaner families

A multidisciplinary survey of the clinical and genetic characteristics of 26 Belgian and 32 Afrikaner families with biopsy-proven pseudoxanthoma elasticum (PXE) was undertaken. The major PXE phenotype emerging from this study is very similar in both patient groups and is characterized by severe ophthalmologic manifestations with variable, mild cutaneous and vascular symptoms. In the families with more than one affected relative, segregation analysis is compatible with autosomal recessive inheritance in both groups. It is suggested that the PXE phenotype of these Belgian and Afrikaner patients is distinct from the other recognized PXE subtypes. The phenotypic resemblance in both patient groups raises the question whether a similar genetic mechanism is involved.

Epiphyseal stippling in acrodysostosis

Widespread epiphyseal stippling was demonstrated radiologically during the early months of life in 7 children with acrodysostosis. This finding, which does not seem to have been previously documented in this disorder, is important in the differential diagnosis.

Marfan syndrome: a diagnostic dilemma

During a 17-year period (1971-1988), the Marfan syndrome was diagnosed in 66 patients seen through the Department of Human Genetics, Medical School, University of Cape Town. Following reappraisal and application of the Pyeritz criteria, this diagnosis was confirmed in 33. Of the others, 17 with tall stature and a Marfanoid habitus had insufficient additional manifestations for firm diagnosis and were eliminated from the series. Sixteen had Marfanoid habitus, tall stature, arachnodactyly and other abnormalities which might have indicated the presence of a different syndrome. The difficulty in making a clinical diagnosis of the Marfan syndrome is stressed and emphasizes the need for a biomolecular marker.

Osteogenesis imperfecta with congenital joint contractures (Bruck syndrome)

Five children from three unrelated families were born with symmetrical contractures of the knees, ankles and feet. An initial diagnosis of arthrogryposis multiplex was made, but frequent fracturing occurred after walking commenced and it was then recognised that the children had osteogenesis imperfecta. The pathogenesis of the congenital contractures is unknown, but the symmetry and lack of evidence of prior fracturing is suggestive of articular immobility during early intra-uterine development. The consistency of the anatomical distribution of the contractures, in the setting of a uniform OI phenotype, is suggestive of syndromic identity. A similar case was documented by Alfred Bruck in 1897 and we propose that the eponymous designation "Bruck syndrome" should be applied to the disorder.

Two rare developmental defects of the lower limbs with confirmation of the Lewin and Opitz hypothesis on the fibular and tibial developmental fields

We report on two unrelated patients with malformations of the lower limbs. One had a unilateral apparent doubling of the volume of the femur with distal bifurcation, shortness of the tibiae, absence of fibulae, and lateral ray deficiencies of both feet. The other had a partial duplication of the distal left femur, hypoplasia and proximal dislocation of the ipsilateral tibia, syndactyly of the right 1st and 2nd toes, and preaxial polydactyly of the left foot. This report supports the hypothesis of Lewin and Opitz on the presence of two distinct fields of development: the fibular and the tibial.

Radial ray defects and associated anomalies

In a series of 34 patients with defects of the radial ray, 24 individuals had additional clinical manifestations. A firm syndromic diagnosis could be reached in 17 persons (TAR syndrome 4, Holt-Oram syndrome 8, Fanconi anaemia 2, VATER association 2, Radial ray-choanal atresia 1). In the remainder, no specific diagnosis could be established. The heterogeneity of radial ray syndromes has important implications for prognostication and genetic counselling.

Pseudoxanthoma elasticum (Grönblad-Strandberg syndrome)

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New autosomal dominant radial ray hypoplasia syndrome

Radial ray anomalies can occur as isolated defects [Temtamy and McKusick, 1978] or as components of genetic syndromes, which are delineated on the basis of the associated anomalies, inheritance, chromosome, or hematological abnormalities. Syndrome identification is important because of the prognostic implications of the particular hematologic, oncologic, and clinical complications specific for each condition. In some instances overlap and variable expression of the manifestations associated with the radial ray defect confuse nosological definition and genetic counselling. In this paper we describe a father and his 2 daughters, who manifested variable defects of the radial ray and concurrent choanal malformations and esotropia. This apparently autosomal dominant condition differs from other radial ray hypoplasia disorders with respect to the associated anomalies and the absence of any hematologic or chromosomal aberrations.