Conradi-Hünermann-Happle syndrome (CDPX2, OMIM 302960) is an X-linked dominant inherited disorder caused by variants in the EBP gene, which primarily affects the skin, bones, and eyes. To describe the clinical manifestations and genetic mutation in a 7-year-old girl presenting with severe scoliosis, hydronephrosis, and other skeletal abnormalities. The patient's medical history was collected from birth. Exome sequencing was performed to identify candidate genes, and the detected variant was confirmed by Sanger sequencing. Exome sequencing revealed a de novo EBP mutation (c.452A>G, p.Gln151Arg) in the patient. The patient was diagnosed with X-linked chondrodysplasia punctata type 2 (CDPX2). This novel missense mutation expands the mutation spectrum of CDPX2 and underscores the clinical utility of exome sequencing in diagnosing this condition.

Chondrodysplasia punctata is a rare hereditary disorder that affects bone development. The disease is primarily caused by mutations in the emopamil binding protein (EBP) gene, leading to X-linked dominant metabolic enzyme abnormalities. This study aims to report a novel EBP mutation in X-linked dominant chondrodysplasia punctata type 2 (CDPX2), expanding the genetic spectrum of the disease and highlighting the critical role of combined clinical and genetic diagnosis in guiding prenatal counseling and postnatal management. Multiple prenatal ultrasounds revealed misalignment of the spinal column and short femur. Postnatally, the infant exhibited craniofacial defects, short limbs, congenital ichthyosis, and alopecia. Radiographic examination revealed multiple punctate calcifications bilaterally in the pyramids, ischium, pubis, and calcaneus. Whole-exome sequencing of the family revealed a heterozygous mutation, c.204G>A (p.Trp68Ter), in the EBP gene in the affected infant, which is a new pathogenic mutation. The infant received continuous positive airway pressure support for respiratory distress, which was discontinued after 7 days due to clinical improvement. At discharge, respiratory status was stable. Follow-up at 3 months showed significant growth delay: weight 4.6 kg (<3rd percentile) and length 54.5 cm (9th percentile). This case underscores that meticulous physical examination combined with genetic analysis is critical for diagnosing CDPX2. Early identification of EBP mutations enables accurate prenatal counseling and risk assessment for future pregnancies. In primary hypoparathyroidism with hypocalcemia and hyperphosphatemia, deficient parathyroid hormone (PTH) secretion most commonly occurs from surgical excision of, or damage to, the parathyroid glands. The term idiopathic hypoparathyroidism describes isolated cases when a cause is not obvious, and there is no family history. However, hypoparathyroidism is also a feature common to a variety of hereditable syndromes that may present de novo. Familial isolated hypoparathyroidism may show autosomal dominant, autosomal recessive, or X-linked inheritance. Genes involved include PTH, SOX3, CASR, GNA11 and GCM2. Parathyroid hypoplasia is a frequent feature of 22q11.2 deletion syndrome with involvement of the TBX1 gene. The Hypoparathyroidism, Nerve Deafness, and Renal Dysplasia syndrome is due to haploinsufficiency of the GATA3 gene. Antibodies against parathyroid tissue are found in isolated hypoparathyroidism or combined with other endocrine deficiencies. Antibodies against the CASR occur in type 1 autoimmune polyglandular syndrome, due to mutations of the AIRE gene, or in acquired hypoparathyroidism. Disorders characterized by end-organ resistance to PTH are described collectively by the term pseudohypoparathyroidism (PHP), and PHP1A and PHP1B are caused by maternally-inherited changes at the imprinted GNAS complex gene that encodes the Gsα protein. Deleterious mutations of the PTH1R gene show resistance to PTH and PTHrP and present as Blomstrand lethal chondrodysplasia, Eiken syndrome, endochondromatosis, and primary failure of tooth eruption. Calcium and vitamin D are the standard therapy for the management of hypoparathyroidism, with hormone replacement [recombinant human PTH(1-84)] therapy recently becoming an option. Calcilytics, PTH analogs, and orally active small molecule PTH1R agonists may, in the future, join the treatment armamentarium. For complete coverage of all related areas of Endocrinology, please visit our on-line FREE web-text, WWW.ENDOTEXT.ORG.

Greenberg dysplasia is a rare, autosomal recessive, prenatal lethal bone dysplasia caused by biallelic pathogenic variants in the lamin B receptor (LBR) gene. Pathogenic variants in LBR are also associated with Pelger-Huët anomaly, an autosomal dominant benign abnormality of the nuclear shape and chromatin organization of blood granulocytes, and Pelger-Huët anomaly with variable skeletal anomalies, a mild, regressing to moderate-severe autosomal recessive condition. Conditions with abnormal sterol metabolism and different genetic basis have clinical and radiographic features similar to Greenberg dysplasia, for example X-linked dominant chondrodysplasia punctata, Conradi-Hünermann type, and CHILD syndrome, and other conditions with unknown genetic etiology display very similar features, for example, dappled diaphyseal dysplasia and Astley-Kendall dysplasia. We present a fetus with typical clinical and radiographic features of Greenberg dysplasia, and review the literature. Genetic testing confirmed the diagnosis Greenberg dysplasia: homozygosity for a pathogenic variant in LBR. Comparing the clinical and radiographic phenotypes of Greenberg dysplasia, dappled diaphyseal dysplasia, and Astley-Kendall dysplasia, we suggest that these are allelic disorders.

X-linked dominant chondrodysplasia punctata type 2 (CDPX2) is a condition involving facial, skin, and skeletal dysplasia as a result of a mutation in emopamil binding protein (EBP). It usually presents with mild symptoms in female patients but is fatal in male patients. A fetus was diagnosed with asymmetrical short limbs and a narrow and small thorax by prenatal ultrasound examination at 24+5 weeks gestation. The pregnancy was terminated at 27 weeks of gestation; gross examination, postnatal X-ray and, whole exome analysis were performed to clarify the diagnosis. A provisional diagnosis of fatal skeletal dysplasia was given and the definite diagnosis of CDPX2 was based on postnatal X-ray and genetic testing of the aborted fetus. The pregnancy was terminated at 27 weeks' gestation after a fetal ultrasound indicated a severe abnormal phenotype. Whole exome analysis of aborted tissue confirmed EBP mutation in this case. Unlike most case reports, this female patient presented a severe phenotype that was considered to be related to X-chromosome inactivation. Chondrodysplasia punctata (CDP) should be considered if prenatal ultrasound shows high punctuate echoes at the metaphysis of long bones and asymmetrical short lower limbs. Postnatal X-ray and measurement of sterol levels in the amniotic fluid may aid in the diagnosis of CDP, but the condition can be confirmed with genetic testing of a blood sample or aborted tissue after delivery.

Conradi-Hünermann-Happle syndrome, or X-linked dominant chondrodysplasia punctata type 2 (CDPX2), is a genodermatosis caused by mutations in EBP. While typically lethal in males, females with CDPX2 generally manifest by infancy or childhood with variable features including congenital ichthyosiform erythroderma, chondrodysplasia punctata, asymmetric shortening of the long bones, and cataracts. We present a 36-year-old female with short stature, rhizomelic and asymmetric limb shortening, severe scoliosis, a sectorial cataract, and no family history of CDPX2. Whole exome sequencing (WES) revealed a p.Arg63del mutation in EBP, and biochemical studies confirmed a diagnosis of CDPX2. Short stature in combination with ichthyosis or alopecia, cataracts, and limb shortening in an adult should prompt consideration of a diagnosis of CDPX2. As in many genetic syndromes, the hallmark features of CDPX2 in pediatric patients are not readily identifiable in adults. This demonstrates the utility of WES as a diagnostic tool in the evaluation of adults with genetic disorders.