Mutations in human TBX3 alter limb, apocrine and genital development in ulnar-mammary syndrome.

Ulnar-mammary syndrome is a rare pleiotropic disorder affecting limb, apocrine gland, tooth and genital development. We demonstrate that mutations in human TBX3, a member of the T-box gene family, cause ulnar-mammary syndrome in two families. Each mutation (a single nucleotide deletion and a splice-site mutation) is predicted to cause haploinsufficiency of TBX3, implying that critical levels of this transcription factor are required for morphogenesis of several organs. Limb abnormalities of ulnar-mammary syndrome involve posterior elements. Mutations in TBX5, a related and linked gene, cause anterior limb abnormalities in Holt-Oram syndrome. We suggest that during the evolution of TBX3 and TBX5 from a common ancestral gene, each has acquired specific yet complementary roles in patterning the mammalian upper limb.

Hereditary pancreatitis. Nonspecificity of aminoaciduria and diagnosis of occult disease.

Hereditary pancreatitis appears in many different ways and in a variety of age groups, spanning both pediatric and adult medicine. The variable expression of hereditary pancreatitis is emphasized by the difficulty in diagnosing it in a patient obviously at risk because of a severely affected father and son. The morphine prostigmine test and hypotonic duodenogram were most helpful. Aminoaciduria previously associated with this disorder is coincidental or nonspecifically related to acute pancreatic inflammation. The increased risk for pancreatic carcinoma (about 20%) is emphasized by the concern for that complication in the proband's grandfather.

Declining insulin requirement in the late first trimester of diabetic pregnancy.

OBJECTIVE: To investigate whether pregnancies complicated by type 1 diabetes are associated with a decrease in first-trimester insulin requirement. RESEARCH DESIGN AND METHODS: We examined the weekly insulin requirement (as units per kilogram per day) during the first trimester of pregnancy in diabetic women in the Diabetes in Early Pregnancy Study (DIEP) with accurate gestational dating, regular glucose monitoring, daily insulin-dose recording, and monthly glycohemoglobin measurements. RESULTS: In pregnancies that resulted in live-born full-term singleton infants, a significant 18% increase in mean weekly dosage was observed between weeks 3 and 7 (P = 0.000), followed by a significant 9% decline from week 7 through week 15 (P = 0.000). Further testing localized a significant change in insulin dose in the interval beginning weeks 7-8 and ending weeks 11-12 (P = 0.014). Within this interval, the maximum decrease was between weeks 9 and 10 (mean), 10 and 11 (median), and 8 and 9 (most frequent maximal decrease). To determine whether prior poor glucose control exaggerated these trends, we categorized the women based on their glycohemoglobin values: <2 SDs above the mean of a normal population (subgroup 1), 2-4 SDs (subgroup 2), and >4 SDs (subgroup 3) at baseline. Late first-trimester declines in dosage were statistically significant in subgroup 2 (P = 0.002) and subgroups 2 and 3 together (P = 0.003). Similarly, women with BMI >27.0 had a greater initial insulin rise and then fall compared with leaner women. CONCLUSIONS: Observations in the DIEP cohort disclose a mid-first-trimester decline in insulin requirement in type 1 diabetic pregnant women. Possible explanations include overinsulinization of previously poorly controlled diabetes, a transient decline in progesterone secretion during the late first-trimester luteo-placental shift in progesterone secretion, or other hormonal shifts. Clinicians should anticipate a clinically meaningful reduction in insulin requirement in the 5-week interval between weeks 7 and 12 of gestation.

Metabolic control and progression of retinopathy. The Diabetes in Early Pregnancy Study. National Institute of Child Health and Human Development Diabetes in Early Pregnancy Study.

OBJECTIVE: To evaluate the role of metabolic control in the progression of diabetic retinopathy during pregnancy. RESEARCH DESIGN AND METHODS: We conducted a prospective cohort study of 155 diabetic women in the Diabetes in Early Pregnancy Study followed from the periconceptional period to 1 month postpartum. Fundus photographs were obtained shortly after conception (95% within 5 weeks of conception) and within 1 month postpartum. Glycosylated hemoglobin was measured weekly during the 1st trimester and monthly thereafter. RESULTS: In the 140 patients who did not have proliferative retinopathy at baseline, progression of retinopathy was seen in 10.3, 21.1, 18.8, and 54.8% of patients with no retinopathy, microaneurysms only, mild nonproliferative retinopathy, and moderate-to-severe nonproliferative retinopathy at baseline, respectively. Proliferative retinopathy developed in 6.3% with mild and 29% with moderate-to-severe baseline retinopathy. Elevated glycosylated hemoglobin at baseline and the magnitude of improvement of glucose control through week 14 were associated with a higher risk of progression of retinopathy (adjusted odds ratio for progression in those with glycohemoglobin > or = 6 SD above the control mean versus those within 2 SD was 2.7; 95% confidence interval was 1.1-7.2; P = 0.039). CONCLUSIONS: The risk for progression of diabetic retinopathy was increased by initial glycosylated hemoglobin elevations as low as 6 SD above the control mean. This increased risk may be due to suboptimal control itself or to the rapid improvement in metabolic control that occurred in early pregnancy. Excellent metabolic control before conception may be required to avoid this increase in risk. Those with moderate-to-severe retinopathy at conception need more careful ophthalmic monitoring, particularly if their diabetes was suboptimally controlled at conception.

Comparison of serum placental protein hormone levels in diabetic and normal pregnancy.

Conflicting data exist concerning maternal serum concentrations of placental hormones during pregnancy in women with diabetes mellitus. To resolve some of these discrepancies, women participating in the NICHD-Diabetes in Early Pregnancy Study were studied. In this collaborative study, pregnancy was identified within 21 days of conception by serum hCG measurements. We prospectively collected 185 blood samples from 35 insulin-dependent diabetic women and 166 blood samples from 31 control women, all between 5 and 37 weeks gestation. Serum concentrations of hCG, pregnancy-specific beta-1-glycoprotein, placental lactogen, and hCG alpha were measured serially. The relationship between serum hormone, fasting blood glucose, 1-h postprandial blood glucose, and glycosylated hemoglobin concentrations was compared. Serum hCG alpha levels were significantly lower in the diabetic women than in control women at multiple time points during the first and second trimesters, while no consistent differences in the serum concentrations of hCG or pregnancy-specific beta-1-glycoprotein were found between pregnant diabetic and control women. Serum placental lactogen levels were significantly lower in diabetic women at 9-10 weeks and 20 weeks gestation. There were no correlations between fasting blood glucose, 1-h postprandial blood glucose, or glycosylated hemoglobin and any of the placental protein levels in the diabetic women. These data are consistent with a defect in synthesis and/or secretion of hCG alpha by the cytotrophoblast during the first two trimesters of pregnancy in insulin-requiring diabetic women.

The genetic and clinical heterogeneity of gonadotropin-releasing hormone deficiency in the human.

Despite recent advances in the understanding of the pathophysiology of Kallmann's syndrome (KS), the patterns of inheritance in the majority of cases of GnRH deficiency in human subjects remain unclear. To define further the genetic and phenotypic variability of this syndrome, detailed family histories were reviewed in 106 cases of GnRH deficiency with or without anosmia [i.e. KS or idiopathic hypogonadotropic hypogonadism (IHH)]. The great majority of cases appeared to be sporadic, with only 19 probands (18%) having at least 1 family member with GnRH deficiency. However, of the families in which the proband was the sole member affected by KS or IHH, 9 had individuals with isolated anosmia, and 8 had a strong history of delayed puberty. If these phenotypes were considered as alternative manifestations of the same genetic defect that presented as KS or IHH in the proband, 34% of the cases in the present series could be considered familial. In these families, the most likely modes of transmission were assessed in several ways, including analysis of probands with KS as a distinct subset, and separate determinations based upon whether the phenotypes of isolated anosmia and/or delayed puberty were considered relevant to the inheritance of KS or IHH. The proportion of familial cases that could be attributable to an X-linked mode of inheritance was no greater than 36% in any of these analyses. We conclude that 1) most cases of GnRH deficiency in humans are sporadic and, thus, could represent new mutations; 2) the X-linked form is the least common among familial cases of KS or IHH; 3) defects in at least two autosomal genes can results in GnRH deficiency; and 4) associated clinical defects may well represent clues to the nature and/or location of these autosomal genes.

The lacrimo-auriculo-dento-digital syndrome.

A mother and son had an autosomal-dominant malformation syndrome that included absence of the lacrimal puncta, obstruction of the nasolacrimal ducts, hearing loss, poor dentition, and abnormal thumbs. The son also had severe hypertension with renal anomalies and absence of several salivary glands. Affected members of the only other reported family also had cup-shaped ears and synostosis of the radius and ulna. Early recognition of this disorder is important because of the possibility that the affected infant may have hearing loss and kidney malformations.

Hereditary late-onset lymphedema.

Two different types of hereditary late-onset lymphedema are presented. In one family the father and one son had recurrent streptococcal lymphangitis beginning in childhood. In the son there was lymphatic hypoplasia in both legs with the infection having only occurred in one. Prophylaxis with penicillin prevented the recurrent lymphangitis. Because of 30 years of untreated lymphangitis, the father has chronic severe lymphedema. The second type, lymphedema associated with extra eyelashes (distichiasis) and a wide spinal canal, occurred in a woman whose lymphedema began at age 12 but in whom the hereditary nature of the disorder was not recognized until she was 29. Both of these types of late-onset lymphedema, lymphedema with lymphangitis and lymphedema with distichiasis, are due to autosomal dominant genes. Both families would have benefited from early diagnosis of the cause of the lymphedema.

Wilms tumor in five cousins.

Wilms tumor developed in five cousins in a family. Two with bilateral tumors have died, but three with unilateral lesions have survived. None of the patients had associated chromosome defects, aniridia, hemihypertrophy, or other anomalies. The pattern of Wilms tumor in the family is consistent with several postulated mechanisms of inheritance of the neoplasm, and shows that relatives within affected families may be at risk.

Reproductive and developmental effects of disinfection by-products in drinking water.

Recent epidemiologic studies have reported associations between the consumption of chlorinated drinking water and reproductive and developmental effects. Here we review the available epidemiologic data, assess the hazard potential posed by exposure to disinfection by-products, identify critical data gaps, and offer recommendations for further research. The epidemiologic evidence supporting associations between exposure to water disinfection by-products (DBPs) and adverse pregnancy outcomes is sparse, and positive findings should be interpreted cautiously. The methods used during the early stages of research in this area have been diverse. Variability in exposure assessment and endpoints makes it difficult to synthesize or combine the available data. Exposure misclassification and unmeasured confounding may have lead to bias in risk estimation. Future studies of reproductive outcome and exposure to chlorinated water should use improved methods for exposure assessment to 1) assure selection of appropriate exposure markers, 2) assess seasonal and annual fluctuations in DBPs, 3) assess variability within the distribution system, and 4) assess exposure through multiple routes such as bathing and showering, as well as consumption. Population-based studies should be conducted to evaluate male and female fertility, conception delay, growth retardation, and specific birth defects. The reproductive and developmental effects of exposure to DBPs could be efficiently explored in ongoing investigations by incorporating valid exposure markers and relevant questionnaire information. Future studies should make use of naturally occurring variability in the concentrations of DBPs and may incorporate biomarkers of exposure and effect in their design. Epidemiologic investigations should be conducted in parallel with laboratory-based and animal studies in a coordinated, multidisciplinary approach.

Brief clinical report: hallux varus and preaxial polysyndactyly in brothers.

Two brothers with hallux varus of both feet are reported. One brother also had duplication/triplication of the great toes. The parents had no skeletal abnormalities or abnormalities of dermatoglyphics.

Phenotypic overlap of the BBB and G syndromes.

Three males with similar malformations including hypertelorism, telecanthus, cleft lip and palate, and hypospadias, have been evaluated. One also had a laryngotracheoesophageal cleft and therefore was considered to have the G syndrome. The other two had no stridor, aspiration, or difficulty swallowing, and were considered to have the BBB syndrome. Both disorders are associated with multiple malformations and can be most readily distinguished by the presence of laryngoesophageal abnormalities in the G syndrome and differences in facial features evident later in childhood. The BBB syndrome appears to be inherited as an X-linked disorder with the affected female showing only telecanthus and hypertelorism. The G syndrome exhibits autosomal dominant inheritance with males more severely affected, although a few few females have had serious malformations in addition to telecanthus and hypertelorism. In the family with the G syndrome evaluated for this report, the mother of the affected infant had telecanthus, hypertelorism, and anosmia, the latter a feature not previously noted in this disorder.

Brief clinical report: an X-linked mental retardation syndrome with craniofacial abnormalities, microcephaly and club foot.

A male infant, who died of renal insufficiency at 6 months, had 2 similarly affected maternal uncles who died at 16 and 6 months respectively. Their manifestations include microcephaly, a large anterior fontanel, short nose with anteverted nostrils, club foot deformity, retarded psychomotor development and, in the index case only, kidney hypoplasia and dysplasia. The 2 obligatory carriers of this evidently X-linked recessive syndrome had no physical abnormalities.

Pena-Shokeir phenotype in sibs with macrocephaly but without growth retardation.

A number of more or less distinct subgroups with the Pena-Shokeir phenotype have been identified. We studied two brothers with the Pena-Shokeir phenotype who were unusual because they had macrocephaly and normal growth. In the second sib, no neuromuscular abnormalities were found at autopsy. Among the subgroups with Pena-Shokeir phenotype, these sibs resemble the family reported by Ohlsson et al. [1988] more than the other subgroups that have been proposed. In addition, abnormalities were detected by prenatal ultrasonography during the 18th week of gestation of the second fetus. This finding provides additional evidence that this phenotype may be detected early enough in gestation to consider intervention.

Multiple congenital anomalies/mental retardation (MCA/MR) syndrome due to partial 1q duplication and possible 18p deletion: a study of four individuals in two families.

We have evaluated four individuals from two unrelated families with a similar multiple congenital anomalies/mental retardation (MCA/MR) syndrome due to partial duplication of chromosome 1q and possible deletion 18p. In both families the mothers and several relatives were carriers of the balanced translocation rcp t(1;18) (q42;p11). The features which the four have in common are relative macrocephaly, prominent forehead, micrognathia, and highly arched palate; three of the four individuals have short stature, scoliosis, kyphosis, hirsutism, camptodactyly, sacral dimple, repaired inguinal hernias, and eye abnormalities. Reproductive histories of five balanced translocation carriers in these families indicate that they have a high risk of spontaneous abortions and infants with multiple malformations.

Brief clinical report: syndrome of telecanthus, hypertelorism, strabismus, and pes cavus in father and son.

We report on a father and son who have telecanthus, hypertelorism, strabismus, and pes cavus. In addition, the son has hypospadias, bilateral inguinal hernia, clinodactyly and camptodactyly of fingers bilaterally, a small tissue mass on the tip of his nose, and radiographic findings including flared metaphyses of long bones and osteopenia.

Lessons on objectivity in clinical studies.

Clinical assessments made with measuring devices are generally considered "objective" and "accurate" and are, therefore, more discriminating than subjective assessments. We show that the choice of measuring devices or non-standardized landmarks to be used with the measuring devices affect the "accuracy" of the "objective" findings.

Unilateral carpal bone deformity in mother and son.

We report on a mother and son with unilateral absence of most of the proximal carpal bones, dysplasia of the distal row of carpal bones, and deformity of the forearm. Although carpal bone dysplasia has been reported in several congenital or progressive disorders, unilateral involvement with lack of progression makes this a distinct entity.

Etiologic complexities of diaphragmatic defects: right diaphragmatic hernia, pulmonary hypoplasia/agenesis, and hydrocephalus in sibs.

Here we review the complexities of diaphragmatic defects and describe sibs with small, right diaphragmatic defects with pulmonary hypoplasia/agenesis and hydrocephalus. Despite a poor initial prognosis, the propositus has progressed remarkably well. Antenatal sonographic study detected hydrocephalus but not the diaphragmatic defect in the sib of the propositus. Because diaphragmatic defects are most commonly found in association with other anomalies and may occur in association with chromosome anomalies careful workup of all affected infants is crucial for accurate genetic counseling.

Type III tracheal agenesis with familial tetralogy of Fallot and absent pulmonary valve syndrome.

We describe a female infant born at 33 weeks gestation diagnosed postnatally with a previously unreported phenotype consisting of Type III tracheal agenesis plus tetralogy of Fallot with absent pulmonary valve. She was delivered to a mother who had the same congenital heart malformation, but no detectable tracheal abnormality. We discuss possible etiologies of these malformations.