Obstetrics, genetics, and litigation.

INTRODUCTION: Claims of medical negligence are universal. Unexpected adverse pregnancy outcome may trigger litigation. Such outcomes, especially with neurodevelopmental sequelae, may be compounded by a genetic disorder, congenital abnormality, or syndrome. MATERIAL AND METHODS: This is a report of 297 cases in which a pregnancy complication, error, or incident occurred that was followed by progeny with a genetic disorder, congenital abnormality, or syndrome that spawned litigation. The author assessed, opined, and in many cases, testified about causation. RESULTS: Pregnancies complicated by hypoxic ischemic encephalopathy were not infrequently compounded by offspring with a genetic disorder, congenital abnormality, or syndrome. Multiple cases were brought because of missed ultrasound or laboratory diagnoses, or failures in carrier detection. Teratogenic medication prescribed before or during pregnancy invited legal purview. Failure to refer (or confer) for genetic evaluation or counseling in the face of significant risk, occurred repeatedly. Ethical breaches and hubris promptly led to litigation. CONCLUSIONS: Many lessons and recommendations emerge in this report. These include the realization that the vast majority of errors in this series involved at least two caregivers, serial ultrasound studies are important, decreased fetal movements may signal a genetic disorder, congenital abnormality, or syndrome, family history and ethnicity are vital, cognitive biases profoundly affect decision-making. Finally, the simplest of errors have the potential for causing life-long grief.

Truncating variants in UBAP1 associated with childhood-onset nonsyndromic hereditary spastic paraplegia.

Hereditary spastic paraplegia (HSP) is a group of disorders with predominant symptoms of lower-extremity weakness and spasticity. Despite the delineation of numerous genetic causes of HSP, a significant portion of individuals with HSP remain molecularly undiagnosed. Through exome sequencing, we identified five unrelated families with childhood-onset nonsyndromic HSP, all presenting with progressive spastic gait, leg clonus, and toe walking starting from 7 to 8 years old. A recurrent two-base pair deletion (c.426_427delGA, p.K143Sfs*15) in the UBAP1 gene was found in four families, and a similar variant (c.475_476delTT, p.F159*) was detected in a fifth family. The variant was confirmed to be de novo in two families and inherited from an affected parent in two other families. RNA studies performed in lymphocytes from one patient with the de novo c.426_427delGA variant demonstrated escape of nonsense-mediated decay of the UBAP1 mutant transcript, suggesting the generation of a truncated protein. Both variants identified in this study are predicted to result in truncated proteins losing the capacity of binding to ubiquitinated proteins, hence appearing to exhibit a dominant-negative effect on the normal function of the endosome-specific endosomal sorting complexes required for the transport-I complex.

A contiguous microdeletion syndrome at Xp23.13 with non-obstructive azoospermia and congenital cataracts.

Non-obstructive azoospermia accounts for 10-15% of male infertility, resulting in 60% of all cases of azoospermia and affecting about 1% of the male population. About 30% of these cases are due to Y chromosome microdeletions, chromosome abnormalities, or hormonal disorders. Pathogenic variants in genes on the sex chromosomes have key roles in spermatogenic failure. The co-occurrence of azoospermia and congenital cataracts ranges between 1 in 165,000 and 1 in 500,000. Our 28-year-old patient with normal intelligence and abnormally shaped teeth presented with both disorders. A microarray revealed a microdeletion at Xp23.13 with a whole NHS gene deletion as well as a contiguous deletion of two other genes [SCML1 and RAI2]. This observation represents the first report of non-obstructive azoospermia with congenital cataracts and a contiguous deletion of the SCML1 gene, a transcript of which is exclusively expressed in the testis. SCML1 is the putative culprit gene, which requires functional study or animal experiments. Our analysis of 60 known spermatogenesis failure-related genes by whole-exome sequencing revealed no other candidate. The Nance-Horan syndrome due to pathogenic variants in the NHS gene at Xp23.13 including whole gene deletion does not have azoospermia as a feature. Our report adds to the completeness of genetic counseling for an individual with azoospermia and congenital cataracts.

Identification of a dominant MYH11 causal variant in chronic intestinal pseudo-obstruction: Results of whole-exome sequencing.

Chronic Intestinal Pseudo-Obstruction (CIPO) is a rare gastrointestinal disorder, which affects the smooth muscle contractions of the gastrointestinal tract. Dominant mutations in the smooth muscle actin gene, ACTG2, accounts for 44%-50% of CIPO patients. Other recessive or X-linked genes, including MYLK, LMOD1, RAD21, MYH11, MYL9, and FLNA were reported in single cases. In this study, we used Whole-Exome Sequencing (WES) to study 23 independent CIPO families including one extended family with 13 affected members. A dominantly inherited rare mutation, c.5819delC (p.Pro1940HisfsTer91), in the smooth muscle myosin gene, MYH11, was found in the extended family, shared by 7 affected family members but not by 3 unaffected family members with available DNA, suggesting a high probability of genetic linkage. Gene burden analysis indicates that additional genes, COL4A1, FBLN1 and HK2, may be associated with the disease. This study expanded our understanding of CIPO etiology and provided additional genetic evidence to physicians and genetic counselors for CIPO diagnosis.

Diagnosis of Chronic Intestinal Pseudo-obstruction and Megacystis by Sequencing the ACTG2 Gene.

OBJECTIVES: The diagnosis of chronic intestinal pseudo-obstruction has depended on clinical features, manometry, and imaging. This report aimed to determine the efficacy of sequencing the actin γ-2 (ACTG2) gene for diagnosis. In addition, the goal was to determine how often a mutation would be found in our randomly collected cohort of probands and those probands published previously. METHODS: Whole exome sequencing was performed in 4 probands with chronic intestinal pseudo-obstruction. Subsequently, only the ACTG2 gene was sequenced in another 24 probands (total 28). We analyzed published data of 83 probands and our 28 (total 111) and determined how many had pathogenic variants and the precise genotype. RESULTS: Whole exome and Sanger sequencing revealed a pathogenic variant in the ACTG2 gene in 4 out of 28 of our probands and in 45 out of 83 published probands (49/111 [44.1%]). Moreover, a mutational hotspot in the ACTG2 gene was recognized. Genetic heterogeneity is evident. CONCLUSIONS: Pooled gene sequencing results from 1 individual in each of 111 families enabled a precise diagnosis of an ACTG2 mutation in 49 (44%). The benefit to patients and families of early confirmation of a motility disorder not only helps avoid unnecessary intervention, but also enables institution of appropriate treatments and avoidance of secondary disorders such as malnutrition and poor growth. Knowledge of a pathogenic variant in a parent, with a 50% risk of recurrence, provides an opportunity for genetic counseling.

Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination.

BACKGROUND: The combination of ataxia and hypogonadism was first described more than a century ago, but its genetic basis has remained elusive. METHODS: We performed whole-exome sequencing in a patient with ataxia and hypogonadotropic hypogonadism, followed by targeted sequencing of candidate genes in similarly affected patients. Neurologic and reproductive endocrine phenotypes were characterized in detail. The effects of sequence variants and the presence of an epistatic interaction were tested in a zebrafish model. RESULTS: Digenic homozygous mutations in RNF216 and OTUD4, which encode a ubiquitin E3 ligase and a deubiquitinase, respectively, were found in three affected siblings in a consanguineous family. Additional screening identified compound heterozygous truncating mutations in RNF216 in an unrelated patient and single heterozygous deleterious mutations in four other patients. Knockdown of rnf216 or otud4 in zebrafish embryos induced defects in the eye, optic tectum, and cerebellum; combinatorial suppression of both genes exacerbated these phenotypes, which were rescued by nonmutant, but not mutant, human RNF216 or OTUD4 messenger RNA. All patients had progressive ataxia and dementia. Neuronal loss was observed in cerebellar pathways and the hippocampus; surviving hippocampal neurons contained ubiquitin-immunoreactive intranuclear inclusions. Defects were detected at the hypothalamic and pituitary levels of the reproductive endocrine axis. CONCLUSIONS: The syndrome of hypogonadotropic hypogonadism, ataxia, and dementia can be caused by inactivating mutations in RNF216 or by the combination of mutations in RNF216 and OTUD4. These findings link disordered ubiquitination to neurodegeneration and reproductive dysfunction and highlight the power of whole-exome sequencing in combination with functional studies to unveil genetic interactions that cause disease. (Funded by the National Institutes of Health and others.).

Whole gene duplication of the PQBP1 gene in syndrome resembling Renpenning.

Renpenning syndrome is a well-described X-linked condition associated with multiple congenital anomalies and intellectual disability [OMIM 309500]. Typical signs include microcephaly, dysmorphic features, short stature, small testes, and lean body build. Renpenning syndrome is caused by mutations in the polyglutamine binding protein 1 (PQBP1) gene. Missense mutations, insertions, deletions, and duplications within the gene have been well-described. We present a 47-year-old male with clinical features resembling Renpenning syndrome. He has moderate intellectual disability, seizures since infancy, short stature, small testes, and dysmorphic features. Of note, our patient is normocephalic. A CT scan at 14 years of age showed cerebral atrophy. He had previously been verbally communicative and had few behavioral issues. Recently, our patient has regressed and has become uncommunicative, displaying little and unclear speech. He now exhibits memory and recognition loss and is uncooperative, aggressive, self-abusive, and incontinent. The reason for his regression within the past 4 years is unclear. SNP microarray analysis (500K) revealed a 4.7 Mb duplication at Xp11.22-p11.23. Multiple ligation probe amplification (MLPA) of the PQBP1 gene contained within this duplicated region confirmed a duplication of the entire PQBP1 gene. Multiple other genes are duplicated within this 4.7 Mb region and may contribute to his phenotype.

Fraternal twins with Aarskog-Scott syndrome due to maternal germline mosaicism.

Aarskog-Scott syndrome is a rare X-linked recessive disorder with characteristic facial, skeletal, and genital abnormalities. We report on Aarskog-Scott syndrome in male dizygotic twins with an identical de novo mutation in FGD1 that resulted from germline mosaicism in the phenotypically normal mother. This is the first report of inheritance by germline mosaicism for the FGD1 gene.

Prenatal molecular diagnosis of tuberous sclerosis complex.

OBJECTIVE: The objective of the study was to report experience with prenatal molecular diagnosis of tuberous sclerosis complex (TSC). STUDY DESIGN: Sequential deoxyribonucleic acid (DNA) studies were performed on amniotic fluid cells and chorionic villi from 50 pregnant women at risk for having a child with TSC. Mutations were determined by gene sequencing and deletion/duplication analysis of the 2 TSC genes. RESULTS: DNA analysis was successful in 48 of 50 tested fetuses. Mutations were precisely identified in a family member (24) (TSC1 [5]; TSC2 [19]) and/or fetus (11) (TSC1 [3]; TSC2 [8]). Novel mutations were found in 19 individual families, and a probable polymorphism was noted in 4. Second-trimester ultrasound detected 18 fetuses with cardiac rhabdomyomas. There was insufficient DNA in 1, whereas 8 of 17 (47%) had a mutation, 6 (75%) being in TSC2. In 4 of 18 cases, a mutation was detected in the fetus for the first time despite a parent known to have TSC. CONCLUSION: The value and utility of prenatal diagnosis of TSC by DNA analysis was demonstrated by the results in this series of 50 pregnancies in women at risk of having affected offspring. A family history of TSC or detection of fetal cardiac rhabdomyoma should prompt genetic evaluation and counseling of parents and the option of prenatal diagnosis.

A 21 years follow-up of a girl patient with a pseudodicentric bisatellited chromosome 22 associated with partial trisomy 22pter-->22q12.1: clinical, cytogenetic and molecular observations.

We present clinical and developmental data on a patient with a de novo recombinant pseudodicentric bisatellited chromosome 22 associated with a partial trisomy 22pter-22q12.1. The patient was evaluated at birth and followed-up until 21 years of age. Clinical findings include facial and digital dysmorphism, hydrocephalus and postnatal-onset growth deficiency. The patient showed bilateral microphthalmia with severe palpebral ptosis and coloboma of the iris and left optic nerve. She also has skeletal and neurological abnormalities, cholesteatoma and seizures. She had absence of speech, poor mobility, poor vision and required help with all daily living skills. Conventional chromosome GTG banded analysis showed that the proband had an abnormal karyotype:46,XX,add(22)(q13). Fluorescence in situ hybridization (FISH) analyses and microsatellite markers for DNA polymorphism study ascertained the karyotype as 46,XX,add(22)(q13.3).ish psu dic(22;22)(q13.3;q12.1)(D14Z1/D22Z1++, N25++, ARSA+, PCP22q+). The recombinant chromosome was stable and present in all cells examined. The paternal origin of the psu dic(22;22) chromosome was determined by using five highly polymorphic microsatellite markers located to the region of chromosome 22q11.2-22q13.33. A 22q13.3 monosomy was ruled out with 22q13.3 cosmid probes covering the terminal 22q-140Kb. The proband carried a recombinant pseudodicentric bisatellited chromosome psu dic(22;22)(q13.3;q12.1). To our knowledge, this is the first report of such rearrangement resulting in partial trisomy 22pter-22q12.1.

A fourteen years follow-up of a case of partial trisomy 12q and monosomy 12p recombinants of a familial pericentric inversion of chromosome 12: clinical, cytogenetic and molecular observations.

Partial trisomy 12q and monosomy 12p lead to multiple malformation syndromes. Only four cases were previously reported with the association of these two aneusomies resulting from a familial pericentric inversion of chromosome 12. We report on the clinical, cytogenetic and molecular findings in a boy with an unbalanced karyotype which resulted from a familial pericentric inversion of chromosome 12. The patient was evaluated at birth and followed up until 14 years of age. He showed severe mental retardation, seizures, and dysmorphic features related both to a trisomy 12q and a monosomy 12p. Chromosome breakpoint BAC-FISH mapping revealed that the rec(12) chromosome had a terminal deletion of a 6.7Mb region extending from 12pter to 12p13.31 and a duplicated region of 19.8Mb extending from 12qter to 12q24.13. The findings from the case reported here emphasize the occurrence of some consistent clinical features and illustrate the deficiencies associated with the recombinants from the inversion inv(12)(p13.31q24.13)mat.

A de novo complex chromosome rearrangement involving chromosomes 2, 3, 5, 9 and 11 detected prenatally and studied postnatally by conventional cytogenetics and molecular cytogenetic analyses.

OBJECTIVE: To describe a de novo complex chromosome rearrangement(CCR) detected prenatally and studied afterbirth. METHODS: Conventional cytogenetics and fluorescent in situ hybridization (FISH) were performed on amniotic fluid and peripheral blood. High-resolution comparative genomic hybridization (HR-CGH) analysis was made postnatally. RESULTS: Prenatal/postnatal cytogenetic, FISH and HR-CGH analyses revealed an apparently balanced de novo CCR ascertained as 46,XY,t(2; 3;9)(q21;p24;q22),der(5)inv(5)(?p11q13)t(5; 11)(?p13;q25),ins(5; 3)(?p13;?p23p24). At 9 months,the child has neither congenital anomalies nor evidence of delayed psychomotor development. CONCLUSIONS: Our report describes a rare CCR detected prenatally and shows the usefulness of FISH and CGH in complementing conventional cytogenetics.

The "New Genetics" in Clinical Practice: A Brief Primer.

Major advances in human genetics have led to the identification of 4451 genes to date with disease-carrying mutations, thereby enabling precise diagnoses of all of these monogenic disorders. Limitations to the use of the "new genetics" do exist, however, including the recognition of genetic heterogeneity, many variants of unknown significance, and incidental diagnoses. This article reviews information to help use these advances to aid accurate diagnoses, identify carriers, and determine prenatal diagnoses, providing opportunities to avoid or prevent serious and fatal genetic disorders.

Gene sequencing in neonates and infants with the long QT syndrome.

The objective was to analyze the clinical and molecular findings in a cohort of neonates and infants with the autosomal dominant long QT syndrome (LQTS). Those affected face a high risk of ventricular arrhythmia resulting in syncope, seizure or sudden death. Blood samples submitted for molecular diagnostic studies on 7 infants were subject to DNA extraction and mutation analysis of 18 selected exons in 5 LQTS genes (KCNQ1, HERG, SCN5A, KCNE1, and KCNE2). We detected 11 mutations in these 7 patients. Four patients had 2 mutations in 1 gene (compound heterozygotes) or 2 different genes (digenic inheritance), while 3 patients had 1 mutation each. Except for 1 mutation in KCNE1, all other mutations were detected alone or in combination within HERG and the SCN5A genes. Four of the mutations we found are novel. The lethal nature of the LQTS demands careful attention to the family history and prompt and precise diagnosis and treatment with serious consideration of endocardial pacemaker implantation. While much larger studies are needed, our data suggest that compound heterozygotes or those with 2 mutations in different genes are likely to have a more severe LQTS including early manifestations in neonates and infants.

Lies, damned lies, and medical experts: the abrogation of responsibility by specialty organizations and a call for action.

The festering problem of medical expert witnesses proffering false testimony in court remains. A review of the many proposed reforms to resolve this chronic and outrageous practice has indicated little progress despite a resolution by the American Medical Association enunciating that medical expert witness testimony is effectively the practice of medicine. A questionnaire was sent to 36 specialty organizations to determine whether they had established guidelines, position statements, policies, or bylaws that govern the disciplinary management of their members who testify falsely. Responses were obtained from all 36 specialty organizations and showed that over 80% had no definitive disciplinary policies to deal with this egregious practice. This finding is all the more surprising given repeated judicial and other exhortations to professional organizations to "police themselves." To address the abrogation of responsibility by specialty organizations, new stringent disciplinary steps are proposed to exorcise the despicable practice of false expert witness testimony from the practice of medicine.