Short stature and growth hormone deficiency in a subset of patients with Potocki-Lupski syndrome: Expanding the phenotype of PTLS

Fetal congenital talipes equinovarus: genomic abnormalities and obstetric follow-up results

OBJECTIVE

The etiology of congenital talipes equinovarus (CTEV) is unknown, and the relationship between chromosome microdeletion/microduplication and fetal CTEV is rarely reported. In this study, we retrospectively analyzed fetal CTEV to explore the relationship among the CTEV phenotype, chromosome microdeletion/microduplication, and obstetric outcomes.

METHODS

Chromosome karyotype analysis and single nucleotide polymorphism (SNP) array were performed for the 68 fetuses with CTEV.

RESULTS

An SNP array was performed for 68 fetuses with CTEV; pathogenic copy number variations (CNVs) were detected in eight cases (11.8%, 8/68). In addition to one case consistent with karyotype analysis, the SNP array revealed seven additional pathogenic CNVs, including three with 22q11.21 microdeletions, two with 17p12p11.2 microduplications, one with 15q11.2 microdeletions, and one with 7q11.23 microduplications. Of the seven cases carrying pathogenic CNVs, three were tested for family genetics; of these, one was de novo, and two were inherited from either the father or mother. In total, 68 fetuses with CTEV were initially identified, of which 66 cases successfully followed-up. Of these, 9 were terminated, 2 died in utero, and 55 were live births. In 9 cases, no clinical manifestations of CTEV were found at birth; the false-positive rate of prenatal ultrasound CTEVdiagnosis was thus 13.6% (9/66).

CONCLUSION

CTEV was associated with chromosome microdeletion/microduplication, the most common of which was 22q11.21 microdeletion, followed by 17p12p11.2 microduplication. Thus, further genomic detection is recommended for fetuses with CTEV showing no abnormalities on conventional karyotype analysis.

Dental findings and intravenous sedation in a patient with Potocki-Lupski syndrome: A case report

AIMS

Potocki-Lupski syndrome (PTLS), which is caused by the partial duplication of the short arm of autosome 17, is characterized by feeding difficulties associated with muscle hypotonia and dysphagia in infancy, followed by growth retardation and low body weight in later stages. Speech and motor developmental disorders are observed in childhood, accompanied by autism spectrum disorders in several cases. Other disorders include dental and skeletal abnormalities, and associated sleep apnea. Herein, we describe the first case of dental evaluation and treatment under intravenous sedation in a patient with PTLS.

METHODS

A 13-year-old boy with PTLS and intellectual disability was referred for the treatment of dental caries. Routine intraoral examination and dental treatment were not feasible. As the patient had no muscle hypotonia, dysphagia, or severe growth delay, intraoral examination and dental treatment were successfully performed under intravenous sedation. No incidence of intraoral airway obstruction or aspiration was reported. The patient was followed-up post-operatively.

CONCLUSION

PTLS, a newly identified syndrome, is associated with cardiovascular abnormalities, dysphagia, failure to thrive, and sleep apnea, which are potential risk factors for sedation. This case report highlights the importance of facial and oral findings in determining the risks of difficulties in airway management.

A unique Smith-Magenis patient with a de novo intragenic deletion on the maternally inherited overexpressed RAI1 allele

RAI1 is a dosage-sensitive gene whose decreased or increased expression by recurrent and non-recurrent 17p11.2 deletions or duplications causes Smith-Magenis (SMS) or Potocki-Lupski syndromes (PTLS), respectively. Here we report on a 21-year-old female patient showing SMS phenotype who was found to carry a 3.4 kb de novo intragenic RAI1 deletion. Interestingly, a significant increase in RAI1 transcript levels was identified in the patient's, brother's and mother's peripheral blood cells. Allele-specific dosage analysis revealed that the patient's maternally inherited overexpressed RAI1 allele harbors the intragenic deletion, confirming the SMS diagnosis due to the presence of a single wild-type RAI1 functional allele. The mother and brother do not present any PTLS neurologic/behavioral clinical features. Extensive sequencing of RAI1 promoter and predicted regulatory regions showed no potential causative variants accounting for gene overexpression. However, the mother and both children share a novel private missense variant in RAI1 exon 3, currently classified as a VUS (uncertain significance), though predicted by two bioinformatic tools to disrupt the binding site of one specific transcription factor. The reported familial case, the second showing RAI1 overexpression in the absence of RAI1 duplication, may help to understand the regulation of RAI1 dosage sensitivity although its phenotypic effect remains to be determined.

Prenatal genetic testing in 19 fetuses with corpus callosum abnormality

Background

Corpus callosum abnormality (CCA) can lead to epilepsy, moderate severe neurologic or mental retardation. The prognosis of CCA is closely related to genetic etiology. However, copy number variations (CNVs) associated with fetal CCA are still limited and need to be further identified. Only a few scattered cases have been reported to diagnose CCA by whole exome sequencing (WES).

Methods

Karyotyping analysis, copy number variation sequencing (CNV‐seq), chromosomal microarray analysis (CMA) and WES were parallelly performed for prenatal diagnosis of 19 CCA cases.

Results

The total detection rate of karyotyping analysis, CMA (or CNV‐seq) and WES were 15.79% (3/19), 21.05% (4/19) and 40.00% (2/5), respectively. Two cases (case 11 and case 15) were diagnosed as aneuploidy (47, XY, + 13 and 47, XX, + 21) by karyotyping analysis and CNV‐seq. Karyotyping analysis revealed an unknown origin fragment (46,XY,add(13)(p11.2)) in case 3, which was further confirmed to originate from p13.3p11.2 of chromosome 17 by CNV‐seq. CMA revealed arr1q43q44 (238923617–246964774) × 1(8.04 Mb) in case 8 with a negative result of chromosome karyotype. WES revealed that 2 of 5 cases with negative results of karyotyping and CNV‐seq or CMA carried pathogenic genes ALDH7A1 and ARID1B.

Conclusion

Parallel genetic tests showed that CNV‐seq and CMA are able to identify additional, clinically significant cytogenetic information of CCA compared to karyotyping; WES significantly improves the detection rate of genetic etiology of CCA. For the patients with a negative results of CNV‐seq or CMA, further WES test is recommended.

Whole Exome Sequencing Uncovered the Genetic Architecture of Growth Hormone Deficiency Patients

PURPOSE

Congenital growth hormone deficiency (GHD) is a rare and etiologically heterogeneous disease. We aim to screen disease-causing mutations of GHD in a relatively sizable cohort and discover underlying mechanisms via a candidate gene-based mutational burden analysis.

METHODS

We retrospectively analyzed 109 short stature patients associated with hormone deficiency. All patients were classified into two groups: Group I (n=45) with definitive GHD and Group II (n=64) with possible GHD. We analyzed correlation consistency between clinical criteria and molecular findings by whole exome sequencing (WES) in two groups. The patients without a molecular diagnosis (n=90) were compared with 942 in-house controls for the mutational burden of rare mutations in 259 genes biologically related with the GH axis.

RESULTS

In 19 patients with molecular diagnosis, we found 5 possible GHD patients received known molecular diagnosis associated with GHD (NF1 [c.2329T>A, c.7131C>G], GHRHR [c.731G>A], STAT5B [c.1102delC], HRAS [c.187_207dup]). By mutational burden analysis of predicted deleterious variants in 90 patients without molecular diagnosis, we found that POLR3A (p = 0.005), SUFU (p = 0.006), LHX3 (p = 0.021) and CREB3L4 (p = 0.040) represented top genes enriched in GHD patients.

CONCLUSION

Our study revealed the discrepancies between the laboratory testing and molecular diagnosis of GHD. These differences should be considered when for an accurate diagnosis of GHD. We also identified four candidate genes that might be associated with GHD.