Apparently changing patterns of inheritance in Alport's hereditary nephritis: Genetic heterogeneity versus altered diagnostic criteria

With the use of more stringent diagnostic criteria, it has recently been shown that some large pedigrees of Alport's and non-Alport's hereditary nephritis fit sex-linked dominant inheritance (O'Neill et al. 1978). We have used similar diagnostic criteria and have studied a number of Michigan pedigrees in order to see if this hypothesis would be confirmed. We found one small pedigree which definitely shows male-to-male transmission, while one large pedigree is tentatively compatible with sex-linked dominant inheritance. Many of the other pedigrees suggested male-to-male transmission. This Michigan experience is compared to other published reports and found to be consistent, although a trend of fewer reports of male-to-male transmission is seen. We conclude that genetic heterogeneity of Alport's hereditary nephritis is likely.     

Clinical consequences of heterozygosity for autosomal-recessive diseases*,**

Heterozygotes of autosomal-recessive diseases can often be recognized by special heterozygote tests, since enzyme activities are normally reduced in comparison with the normal homozygote state. In Drosophila, the majority of recessive lethal mutations shows a reduction of fitness in heterozygotes, whereas in a strong minority fitness of heterozygotes is increased. This review will be devoted to a consideration of the extent to which heterozygotes for a wide variety of nominally recessive diseases are subject either to an increased liability for common diseases or slight shifts of behavioral characteristics. The available evidence has been collected and will be discussed in three steps: Most studies are available for phenylketonuria. For this group of diseases, a slight reduction of average--especially verbal--I.Q. in heterozygotes has been reported together with signs of a slightly increased cerebral irritability, a possible slight increase of risk for mental disease, and an increase of blood phenylalanine levels in stress situations. The PKU example is used to discuss methodological problems involved in such studies. Other conditions for which relevant deviations in heterozygotes are possible or even likely include among others lipid storage diseases, microcephaly, myoclonus epilepsy, Wilson's disease, galaktokinase deficiency, homocystinuria, recessive myotonia and ataxia- teleangiectasia (increased cancer risk). Since heterozygotes for autosomal recessive diseases are common, it is possible that an appreciable fraction of "multifactorial" genetic liabilities for common, "constitutional" or mental disease might simply be due to heterozygosity for genes whose homozygous affects are already well known. By the same token, much of the "normal" genetic variability influencing cognitive performance (I.Q.)--especially in the lower range--and personality characteristics could also be caused by recessive genes in the heterozygous state.     

Dominantly inherited syndrome of microcephaly and congenital lymphedema

A Chinese family is reported in which microcephaly and congenital lymphedema have been observed in at least 4 generations. This combination of symptoms can be presumed to represent a rare but well defined hereditary syndrome transmitted by an autosomal dominant gene.     

The mitochondrial plasmid of the true slime mold <Emphasis Type="Italic">Physarum polycephalum</Emphasis> bypasses uniparental inheritance by promoting mitochondrial fusion

Mitochondrial DNA (mtDNA) is inherited maternally in most eukaryotes. Linear mitochondrial plasmids in higher plants and fungi are also transmitted from the maternal parent to the progeny. However, mF, which is a mitochondrial linear plasmid of Physarum polycephalum, evades uniparental mitochondrial inheritance. We examined 36 myxamoebal strains of Physarum and isolated three novel mF⁺ strains (JE8, TU111, NG111) that harbored free mF plasmids. These strains were mated with the mF^– strain KM88. Of the three mF^– × mF⁺ crosses, only KM88 × JE8 displayed complete uniparental inheritance. However, in KM88 × TU111 and KM88 × NG111, the mtDNA of KM88 and mF of TU111 and NG111 were inherited by the plasmodia and showed recombination. For example, although the mtDNA of TU111 was eliminated, the mF of TU111 persisted and became inserted into the mtDNA of KM88, such that recombinant mtDNA represented 80% of the total mtDNA. The parental mitochondria fused to yield giant mitochondria with two or more mitochondrial nucleoids. The mF appears to exchange mitochondria from the recipient (paternal) to the donor (maternal) by promoting mitochondrial fusion.The first two authors have equally contributed to this work     

Further delineation of the Beemer–Langer syndrome using concordance rates in affected sibs

Six familial cases of the Beemer–Langer syndrome (BLS) were analyzed to further elucidate the spectrum and frequency of anomalies observed in this disorder. Preaxial polydactyly was found in 3/6 affected sibs, and, therefore, its frequency previously may have been underestimated. Some patients, described as infants affected with the Majewski syndrome (MS) or “atypical” short rib-poly-dactyly conditions, may indeed have BLS. A high frequency of brain defects (16/26) and cleft tongue, oral frenula, and/or natal teeth (13/29) widens the list of typical findings in this syndrome. The specific type of tibial defect seems to be the most important discrimination of the MS and the BLS. © 1994 Wiley-Liss, Inc.     

常染色体显性遗传性枕叶癫癎临床与脑电图1家系6例报告

目的：报道常染色体显性遗传性枕叶癫痫一家系6例。方法：对先证者进行详尽的临床、脑电图(EEG)、录像脑电图(Video—EEG)、头MRA观察。结果：此家系祖孙三代6例，男性女性均有发病，患者大多为8～15岁起病，主要症状为发作性视幻觉、偏身麻木、头痛、呕吐。先证者EEG、Video—EEG、头颅MRA未见异常，家系中继发全面性强直阵挛发作患者EEG见枕颞区异常放电。结论：该家系患者的临床表现、EEG均符合枕叶癫痫诊断，并排除了颅内占位性及血管性病变。该家系符合常染色体显性遗传规律。     

Autosomal dominant inheritance of Klein–Waardenburg syndrome

We report on 2 sibs with the Klein–Waardenburg syndrome; they had dystopia canthorum, blepharophimosis, and bilateral flexion contractures of the fingers. The children's father and paternal aunt are also affected. This report confirms that the Klein–Waardenburg syndrome is an autosomal dominant syndrome.     

Preaxial polydactyly type 4: variability in a large kindred

A five generation family with type 4 preaxial polydactyly is reported. The 21 affected individuals demonstrated variability in expression without apparent sex influence and penetrance which was complete. The deformities were more severe in the feet than the hands. Anteroposterior flatness of the thumbs was the only manifestation of the trait in the hands of several affected family members.     

Autosomal dominant inheritance of adducted thumbs and other digital anomalies

Isolated adducted thumbs is an uncommon malformation that occurs sporadically in the majority of cases although some affected families have been reported. Previously, autosomal dominant inheritance was suggested in two familial cases, but this mode of inheritance has not been confirmed. Here we describe a family with adducted thumbs and other digital anomalies in which seven members (six females and one male) are affected in three consecutive generations. Additionally, the patients showed mild abnormalities of fingers 2nd–4th bilaterally and hypoplasia of the middle phalanx of the 5th fingers. This family represents an autosomal dominant condition that apparently has not been previously reported.     

Isolated mesomelic shortening of the forearm in father and daughter: a new entity in the group of mesomelic dysplasias

In this report we describe the occurrence of severe mesomelic shortening of the forearms due to hypoplasia of the ulnae with severe radial bowing. In contrast to the mesomelic dysplasias, i.e. Langer type of mesomelic dwarfism, this apparently autosomal dominantly inherited skeletal anomaly occurred as an isolated anomaly without concomitant involvement of shanks or other parts of the skeleton, and did not influence final adult height.