Clinical Features and Short-Term Growth Hormone Outcomes in Maternal UPD of Chromosome 20: Five Chinese Patients and a Literature Review.
This study indicates that rhGH exposure may lead to short-term increases in growth among children with UPD(20)mat, but the findings are exploratory and do not confirm treatment efficacy.
Where it sits
this study against the rest of the hgh (somatropin) corpusSummary and findings
This study analyzed five Chinese children with maternally derived uniparental disomy of chromosome 20 (UPD(20)mat) to summarize clinical features and short-term growth outcomes during recombinant human growth hormone (rhGH) therapy. Four patients received rhGH therapy, resulting in a mean increase in height standard deviation scores (Ht-SDS) of +1.18. The findings are exploratory and do not establish efficacy.
Abstract
<h4>Background</h4>Maternally derived uniparental disomy of chromosome 20 [UPD(20)mat], also known as Mulchandani-Bhoj-Conlin syndrome (MBCS), is a rare imprinting disorder with fewer than 30 cases documented to date. It is characterized by prenatal and postnatal growth failure and feeding difficulties. Herein, we aimed to summarize the clinical and growth characteristics of UPD(20)mat and describe short-term growth outcomes during recombinant human growth hormone (rhGH) exposure in affected individuals.<h4>Methods</h4>We retrospectively analyzed five Chinese children with UPD(20)mat genetically evaluated by whole-exome sequencing (WES), methylation-specific multiplex ligation-dependent probe amplification, or short tandem repeat analysis. Clinical manifestations and growth data were collected. Four patients received rhGH therapy and were evaluated for changes in height standard deviation scores (Ht-SDS). In addition, we conducted a structured narrative review of 23 previously published cases identified in PubMed, CNKI, and WanFang through July 19, 2026.<h4>Results</h4>The cohort included three female and two male children, with a median age at diagnosis of 3.4 years. Predominant features included advanced maternal age (3/4), postnatal feeding difficulties with low body mass index (BMI), and low absolute serum insulin-like growth factor-1 concentrations in the available records. Facial dysmorphism was mild and predominantly characterized by a prominent forehead and relative macrocephaly. Neurodevelopmental delay was noted in 4/5 patients. After rhGH treatment (duration: 10-15 months), the four treated patients showed substantial short-term catch-up growth, achieving a mean annualized height velocity of 10.7 cm/year and a mean increase in Ht-SDS of +1.18 (range: +0.7 to +2.0). The narrative review identified postnatal growth failure (93%) and feeding difficulties (100%) as cardinal features.<h4>Conclusion</h4>To our knowledge, this study reports the largest case series of Chinese patients with UPD(20)mat to date, highlighting that neurodevelopmental delay and hypotonia are frequent features of this condition. rhGH exposure was associated with short-term increases in linear growth, but the findings are exploratory and do not establish efficacy. Compared with SRS, facial dysmorphism was mild and non-specific, underscoring the importance of early genetic testing in children with unexplained early-onset growth failure.
Background
This paper addresses the clinical and growth characteristics of maternally derived uniparental disomy of chromosome 20 (UPD(20)mat), a rare imprinting disorder associated with growth failure and feeding difficulties. Prior knowledge indicates that UPD(20)mat is characterized by specific clinical features, but there is limited data on the effects of recombinant human growth hormone (rhGH) therapy in affected individuals. This study is significant as it provides insights into the short-term outcomes of rhGH treatment in a cohort of affected children.
Methods
The study employed a retrospective analysis of five Chinese children diagnosed with UPD(20)mat, evaluated through genetic testing methods including whole-exome sequencing. Four of these patients received rhGH therapy, and their changes in height standard deviation scores (Ht-SDS) were measured over a treatment duration of 10-15 months. A structured narrative review of 23 previously published cases was also conducted.
Results
After rhGH treatment, the four patients exhibited a mean annualized height velocity of 10.7 cm/year and a mean increase in Ht-SDS of +1.18 (range: +0.7 to +2.0). The cohort consisted of three female and two male children, with a median age at diagnosis of 3.4 years. Notably, 93% of previously published cases experienced postnatal growth failure, and 100% reported feeding difficulties.
Interpretation
The results indicate a statistically significant increase in height velocity and Ht-SDS following rhGH treatment, but the clinical significance of these findings is uncertain given the small sample size and exploratory nature of the study. The presence of neurodevelopmental delays and feeding difficulties suggests that these children may require comprehensive management beyond growth hormone therapy. The limitations include the small n and the exploratory nature of the findings, which do not allow for definitive conclusions about the efficacy of rhGH in this population.
Key findings
- Mean annualized height velocity of 10.7 cm/year after rhGH treatment.
- Mean increase in Ht-SDS of +1.18 (range: +0.7 to +2.0) after rhGH treatment.
- Postnatal growth failure observed in 93% of previously published cases.
- Feeding difficulties reported in 100% of previously published cases.
- Median age at diagnosis was 3.4 years.
Limitations
- Small sample size of n=5.
- Exploratory findings do not establish efficacy.
- Retrospective analysis limits causal inference.
- Short treatment duration of 10-15 months.