Ocular findings in Kenny's syndrome

Kenny-Caffey Syndrome Type 2 (KCS2): A New Case Report and Patient Follow-Up Optimization

Background/Objectives: Kenny-Caffey syndrome 2 (KCS2) is a rare cause of hypoparathyroidism, inherited in an autosomal dominant mode, resulting from pathogenic variants of the FAM111A gene, which is implicated in intracellular pathways regulating parathormone (PTH) synthesis and skeletal and parathyroid gland development. Methods: The case of a boy is reported, presenting with the characteristic and newly identified clinical, biochemical, radiological, and genetic abnormalities of KCS2. Results: The proband had noticeable dysmorphic features, and the closure of the anterior fontanel was delayed until the age of 4 years. Biochemical evaluation at several ages revealed persistent hypocalcemia, high normal phosphorous, and inappropriately low normal PTH. To exclude other causes of short stature, the diagnostic approach revealed low levels of IGF-1, and on CNS MRI, small pituitary gland and empty sella. Nocturnal levels of growth hormone were normal. MRI also revealed bilateral symmetrical microphthalmia and torturous optic nerves. Skeletal survey was compatible with cortical thickening and medullary stenosis of the long bones. Genomic data analysis revealed a well-known pathogenic variant of the FAM111A gene (c.1706G>A, p. R569H), which is linked with KCS2 or nanophthalmos. Conclusions: KCS2, although a rare disease, should be included in the differential diagnosis of hypoparathyroidism and short stature. Understanding the association of pathogenic variants with KCS2 phenotypic variability will allow the advancement of clinical genetics and personalized long-term follow-up and will offer insights into the role of the FAM111A gene in the disease pathogenesis and normal embryogenesis of implicated tissues and organs.

Expanding the Phenotypic Spectrum of Kenny-Caffey Syndrome

CONTEXT

Kenny-Caffey syndrome (KCS) is a rare hereditary disorder characterized by short stature, hypoparathyroidism, and electrolyte disturbances. KCS1 and KCS2 are caused by pathogenic variants in TBCE and FAM111A, respectively. Clinically the phenotypes are difficult to distinguish.

OBJECTIVE

The objective was to determine and expand the phenotypic spectrum of KCS1 and KCS2 in order to anticipate complications that may arise in these disorders.

METHODS

We clinically and genetically analyzed 10 KCS2 patients from 7 families. Because we found unusual phenotypes in our cohort, we performed a systematic review of genetically confirmed KCS cases using PubMed and Scopus. Evaluation by 3 researchers led to the inclusion of 26 papers for KCS1 and 16 for KCS2, totaling 205 patients. Data were extracted following the Cochrane guidelines and assessed by 2 independent researchers.

RESULTS

Several patients in our KCS2 cohort presented with intellectual disability (3/10) and chronic kidney disease (6/10), which are not considered common findings in KCS2. Systematic review of all reported KCS cases showed that the phenotypes of KCS1 and KCS2 overlap for postnatal growth retardation (KCS1: 52/52, KCS2: 23/23), low parathyroid hormone levels (121/121, 16/20), electrolyte disturbances (139/139, 24/27), dental abnormalities (47/50, 15/16), ocular abnormalities (57/60, 22/23), and seizures/spasms (103/115, 13/16). Symptoms more prevalent in KCS1 included intellectual disability (74/80, 5/24), whereas in KCS2 bone cortical thickening (1/18, 16/20) and medullary stenosis (7/46, 27/28) were more common.

CONCLUSION

Our case series established chronic kidney disease as a new feature of KCS2. In the literature, we found substantial overlap in the phenotypic spectra of KCS1 and KCS2, but identified intellectual disability and the abnormal bone phenotype as the most distinguishing features.

FAM111A is dispensable for electrolyte homeostasis in mice

Autosomal dominant mutations in FAM111A are causative for Kenny-Caffey syndrome type 2. Patients with Kenny-Caffey syndrome suffer from severe growth retardation, skeletal dysplasia, hypoparathyroidism, hypocalcaemia, hyperphosphataemia and hypomagnesaemia. While recent studies have reported FAM111A to function in antiviral response and DNA replication, its role in regulating electrolyte homeostasis remains unknown. In this study, we assessed the role of FAM111A in the regulation of serum electrolyte balance using a Fam111a knockout (Fam111a-/-) C57BL/6 N mouse model. Fam111a-/- mice displayed normal weight and serum parathyroid hormone (PTH) concentration and exhibited unaltered magnesium, calcium and phosphate levels in serum and 24-hour urine. Expression of calciotropic (including Cabp28k, Trpv5, Klotho and Cyp24a1), magnesiotropic (including Trpm6, Trpm7, Cnnm2 and Cnnm4) and phosphotropic (Slc20a1, Slc20a2, Slc34a1 and Slc34a3) genes in the kidneys, duodenum and colon were not affected by Fam111a depletion. Only Slc34a2 expression was significantly upregulated in the duodenum, but not in the colon. Analysis of femurs showed unaffected bone morphology and density in Fam111a-/- mice. Kidney and parathyroid histology were also normal in Fam111a-/- mice. In conclusion, our study is the first to characterise the function of FAM111A in vivo and we report that mice lacking FAM111A exhibit normal electrolyte homeostasis on a standard diet.

Genotype-phenotype spectrum in isolated and syndromic nanophthalmos

PURPOSE

To (i) describe a series of patients with isolated or syndromic nanophthalmos with the underlying genetic causes, including novel pathogenic variants and their functional characterization and (ii) to study the association of retinal dystrophy in patients with MFRP variants, based on a detailed literature review of genotype-phenotype correlations.

METHODS

Patients with nanophthalmos and available family members received a comprehensive ophthalmological examination. Genetic analysis was based on whole-exome sequencing and variant calling in core genes including MFRP, BEST1, TMEM98, PRSS56, CRB1, GJA1, C1QTNF5, MYRF and FAM111A. A minigene assay was performed for functional characterization of a splice site variant.

RESULTS

Seven patients, aged between three and 65 years, from five unrelated families were included. Novel pathogenic variants in MFRP (c.497C>T, c.899-3C>A, c.1180G>A), and PRSS56 (c.1202C>A), and a recurrent de novo variant in FAM111A (c.1706G>A) in a patient with Kenny-Caffey syndrome type 2, were identified. In addition, we report co-inheritance of MFRP-related nanophthalmos and ADAR-related Aicardi-Goutières syndrome.

CONCLUSION

Nanophthalmos is a genetically heterogeneous condition, and the severity of ocular manifestations appears not to correlate with variants in a specific gene. However, retinal dystrophy is only observed in patients harbouring pathogenic MFRP variants. Furthermore, heterozygous carriers of MFRP and PRSS56 should be screened for the presence of high hyperopia. Identifying nanophthalmos as an isolated condition or as part of a syndrome has implications for counselling and can accelerate the interdisciplinary care of patients.

Optic disc drusen: a systematic review : Up-to-date and future perspective

BACKGROUND

Optic disc drusen (ODD) are acellular deposits in the prelaminar optic nerve head. The most accredited theory is that they are secondary to abnormalities in axonal metabolism and degeneration, but the pathogenesis is not clear to date.

CLINICAL MANIFESTATION

Although ODD are often considered a benign condition, the great majority of patients with ODD show visual field defects and are at higher risk for developing anterior ischemic optic neuropathy. ODD are classified as superficial or buried, with the latter being often misdiagnosed as papilledema with optic nerve head swelling, leading to an unnecessary investigation for causes of increased intracranial pressure.

AIM

The recent technological improvements in OCT imaging which allowed an earlier and more certain diagnosis even of the smallest ODD, renovated the interest around this pathology. However, an updated systematic review is still missing. Therefore, the aim of this work is to provide a concise yet comprehensive overview of the current state of art, focusing on pathophysiology, clinical presentation, diagnostic methods, treatment modalities and potential future perspectives of this condition.

Ophthalmologic Impairment and Intellectual Disability in a Girl Presenting Kenny-Caffey Syndrome Type 2

Kenny-Caffey syndrome (KCS) is a rare genetic condition characterized by growth retardation, bone abnormalities, and hypoparathyroidism. Herein, we report an unusual case of a 10-year-old girl with Kenny-Caffey syndrome type 2 (KCS2) presenting with vision impairment-suspected maculopathy and intellectual disability. Endocrine evaluation showed low calcium and high phosphorus plasma levels. Radiographic evaluation revealed short metacarpal bones and delayed bone age. Sequencing analysis showed a missense variant in FAM111A (R569H), unidentified in her parents. Better understanding of potential neurological and ophthalmological findings in KCS2 patients is important to improve quality of life of these patients as usually they exhibit long survival.

Acquired pseudoduplication of the optic disc in pathologic myopia

PURPOSE

To elucidate the mechanism of acquired pseudoduplication of the optic disc and its association with pathologic myopia.

METHODS

The prevalence of pseudoduplication of the optic disc was estimated by reviewing 128 consecutive patients diagnosed as having pathologic myopia between January 2010 and December 2012. The pseudodisc was investigated at the scleral level using enhanced depth imaging spectral-domain optical coherence tomography to elucidate pathologic changes. Fluorescein angiography or indocyanine green angiography was performed to identify the vessel origin.

RESULTS

Among 128 patients with pathologic myopia, 3 patients (2.3%) showed pseudoduplication of the optic disc. Enhanced depth imaging optical coherence tomography showed chorioretinal atrophy and focal scleral excavation in the area showing the pseudodisc. The round scleral excavation gave the underlying visible peribulbar tissue a pinkish appearance, which could be mistaken as the optic disc. Fluorescein angiography or indocyanine green angiography showed that the vessel within the pseudodisc was the short posterior ciliary artery.

CONCLUSIONS

Although not a common presentation, scleral excavation associated with pathologic myopia accompanied by a ciliary artery penetrating the excavation's center could make a lesion mimicking pseudoduplication of the optic disc.

A recurrent de novo FAM111A mutation causes Kenny-Caffey syndrome type 2

Kenny-Caffey syndrome (KCS) is a rare dysmorphologic syndrome characterized by proportionate short stature, cortical thickening and medullary stenosis of tubular bones, delayed closure of anterior fontanelle, eye abnormalities, and hypoparathyroidism. The autosomal dominant form of KCS (KCS type 2 [KCS2]) is distinguished from the autosomal recessive form of KCS (KCS type 1 [KCS1]), which is caused by mutations of the tubulin-folding cofactor E (TBCE) gene, by the absence of mental retardation. In this study, we recruited four unrelated Japanese patients with typical sporadic KCS2, and performed exome sequencing in three patients and their parents to elucidate the molecular basis of KCS2. The possible candidate genes were explored by a de novo mutation detection method. A single gene, FAM111A (NM_001142519.1), was shared among three families. An identical missense mutation, R569H, was heterozygously detected in all three patients but not in the unaffected family members. This mutation was also found in an additional unrelated patient. These findings are in accordance with those of a recent independent report by a Swiss group that KCS2 is caused by a de novo mutation of FAM111A, and R569H is a hot spot mutation for KCS2. Although the function of FAM111A is not known, this study would provide evidence that FAM111A is a key molecule for normal bone development, height gain, and parathyroid hormone development and/or regulation.

Optical coherence tomography findings of retinal folds in nanophthalmos

Aim. To report the optical coherence tomography (OCT) findings in three members of the same family with nanophthalmos associated with elevated papillomacular retinal fold. Methods. Complete ophthalmic examination as well as ultrasonography and OCT was performed in all patients. Results. Axial lengths ranged from 16.75 mm to 17.48 mm and refractive errors ranged from +17.50 D to +20.50 D. Main fundus findings were the hyperopic crowded, cupless optic disc, and retinal fold through papillomacular region. Macular OCT scans revealed retinal fold with normal retinal pigment epithelium and choriocapillaris. Interpretation. It is presumed that the retinal folds in nanophthalmos result from a redundancy of the retinal layer caused by retarded growth of the scleral, choroidal, and retinal pigment epithelial layers. The anatomic information provided by the current study is consistent with this thesis.

Pseudopapilledema in Kenny-Caffey syndrome

A 21-year-old man with Kenny-Caffey syndrome had been observed since 1993 for hyperopia. Fundus examination revealed swollen optic disks. Further examinations (fluorescein angiography, B-scan ultrasonography, and optical coherence tomography) confirmed the optic nerve head elevation. The authors report a rare case of Kenny-Caffey syndrome with extreme pseudopapilledema. Although uncommon, ophthalmologists should be mindful of this disorder when a patient presents with characteristic findings because severe electrolyte disturbances may complicate the clinical course.

Presumed atypical HDR syndrome associated with Band Keratopathy and pigmentary retinopathy

This report describes presumed atypical hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome associated with unexpected ocular findings. The patient had exotropia, bilateral band keratopathy, and pigmentary retinopathy, including attenuated retinal vessels and atrophy of the retinal pigment epithelium. Even though the calcific plaques were successfully removed, visual acuity in both eyes gradually decreased and electroretinography was extinguished.

Peripapillary choroidal neovascularization associated with kenny syndrome

PURPOSE

To report a case of Kenny-Caffey syndrome with peripapillary choroidal neovascularization.

METHODS

An observational case report with clinical findings demonstrated by wide-field retinal photographic and angiographic evaluation of a patient with Kenny-Caffey syndrome.

RESULTS

Wide-field retinal photography and fluorescein angiography showed characteristic findings seen in Kenny-Caffey syndrome (crowded optic nerves, retinal vascular tortuosity). In addition, the previously undocumented finding of peripapillary choroidal neovascularization is demonstrated.

CONCLUSION

The development of peripapillary choroidal neovascularization can occur in patients with Kenny-Caffey syndrome. The development of this finding may be secondary to abnormalities of the optic nerve inherent in this rare disorder.

Ophthalmic features of hypoparathyroidism-retardation-dysmorphism

Hypoparathyroidism-retardation-dysmorphism (HRD; Sanjad-Sakati Syndrome; Online Mendelian Inheritance in Man [OMIM] #241410) is a rare recessive syndrome predominantly seen on the Arabian Peninsula and characterized by congenital hypoparathyroidism, intrauterine growth retardation, mental retardation, seizures, and a typical facial dysmorphism (prominent forehead, deep-set eyes, and abnormal external ears).(1,2) To date, the same homozygous deletion in TBCE (155-166del) has been reported in all Saudi Arabian patients with HRD(1) as well as in all Saudi Arabian patients with Kenny-Caffey syndrome (OMIM #244460),(1) a syndrome with a phenotype that resembles that of HRD but is characterized by the presence of normal intelligence, late closure of the anterior fontanelle, macrocephaly, and postnatal (rather than prenatal) growth retardation.(1,3) Nanophthalmos and corneal opacity have been documented in Kenny-Caffey syndrome patients,(4) but ocular disease has not been well-described in HRD. We describe the ocular features of four Saudi Arabian HRD children referred to our institution for ocular complaints noted by their parents.

Characterization of optical coherence topography findings in Kenny-Caffey syndrome

An unusual congenital syndrome was first reported in 1966 by Kenny and Linarelli, who described two patients with dwarfism, cortical thickening of the long bones, transient hypocalcemia, and normal intelligence,(1) the radiological features in the condition being reported by Caffey.(2) The constellation of dwarfism, medullary stenosis, transient hypocalcemia, and ophthalmologic abnormalities has been classically recognized as Kenny-Caffey syndrome with additional manifestations ranging from hypoplastic nails, persistent neutropenia, abnormal T-cell function, and neonatal liver disease.(3) Ocular findings range from uncomplicated nanophthalmos with hypermetropia to extreme pseudopapilloedema, vascular tortuosity, and macular crowding. Other reported ophthalmic findings include bilateral band keratopathy,(4) bilateral optic atrophy,(5) and myelinated nerve fibers.(6) We report two cases of Kenny-Caffey syndrome with an ellipsoid macular fold orientated horizontally involving the fovea and document this unusual feature with optical coherence topography (OCT).

Parathyroid Development and the Role of Tubulin Chaperone E

The development of the parathyroid glands involves complex embryonic processes of cell-specific differentiation and migration of the glands from their sites of origin in the pharynx and pharyngeal pouches to their final positions along the ventral midline of the pharyngeal and upper thoracic region. The recognition of several distinct genetic forms of isolated and syndromic hypoparathyroidism led us to review the recent findings on the molecular mechanisms of the development of the parathyroid glands. Although far from being understood, a special emphasis was given to the possible role of tubulin chaperone E (TBCE), which was implicated in the pathogenesis of the hypopathyroidism, retardation and dysmorphism (HRD) syndrome. The novel finding that TBCE plays a critical role in the formation of the parathyroid opens a novel domain of research, not anticipated previously, into the complex process of parathyroid development.

Variant arabe du syndrome de Kenny : à propos d’une famille maghrébine

Kenny syndrome is rare. Clinical feature include severe dwarfism, growth retardation macrocephaly, episodic hypocalcemia, internal cortical thickening and medullary stenosis of tubular bones. Genetic and phenotypic polymorphisms are characteristic. We report the observation of a Tunisian girl with the arabic variant of Kenny syndrome. She had chronic hypoparathyroidism, classic dwarfism, short stature with hormone deficiency, mental retardation and low helper/suppressor ratio. Our patient had two sisters and one brother with the same dysmorphic face and a marked intra-uterine growth retardation. They died from severe infections. Hypoparathyroidism was established in one sister.

Genetics and animal models of hypoparathyroidism

Hypoparathyroidism is a heterogeneous group of disorders with diverse etiologies. During the past decade, major advances have been made towards unraveling the precise cellular and molecular mechanisms that underlie the pathogenesis of this endocrinopathy. Studies of patients afflicted with the disease and of genetically altered mice with strategically engineered mutations have paved new and exciting avenues of investigation into its causes. While focusing on these discoveries, we review areas of controversy and discuss possible approaches for their resolution.

Sanjad-Sakati and autosomal recessive Kenny-Caffey syndromes are allelic: evidence for an ancestral founder mutation and locus refinement

The Sanjad-Sakati syndrome (SSS; MIM241410), an autosomal recessive trait characterized by congenital hypoparathyroidism, growth and mental retardation, seizures, and a characteristic physiognomy, was recently linked to chromosome area 1q42-q43. SSS resembles the autosomal recessive form of Kenny-Caffey syndrome (KCS; MIM244460), with similar manifestations but lacking osteosclerosis. Since KCS was recently linked to the region 1q42-q43, the possibility that this disorder is allelic with SSS was considered. Eight Sanjad-Sakati families from Saudi Arabia were genotyped with polymorphic short tandem repeat markers from the SSS/KCS critical region. A maximum multipoint LOD score of 14.32 was obtained at marker D1S2649, confirming linkage of SSS to the same region as autosomal recessive KCS. Haplotype analysis refined the critical region to 2.6 cM and identified a rare haplotype present in all the SSS disease alleles, indicative of a common founder. In addition to the assignment of the Saudi SSS and Kuwaiti KCS syndromes to overlapping genetic intervals, comparison of the haplotypes unexpectedly demonstrated that the diseases shared an identical haplotype. This finding, combined with the clinical similarity between the two syndromes, suggests that the two conditions are not only allelic but are also caused by the same ancestral mutation.

The autosomal recessive Kenny-Caffey syndrome locus maps to chromosome 1q42-q43

Kenny-Caffey syndrome (KCS) is an osteosclerotic bone dysplasia with associated hypocalcemia and ocular abnormalities. Both autosomal dominant (MIM127000) and autosomal recessive (MIM244460) inheritance patterns have been described. Using eight consanguineous Kuwaiti kindreds, a genome-wide search for linkage to the gene causing the autosomal recessive form of KCS was performed with polymorphic short tandem repeat markers. Significant linkage to a locus situated at chromosome 1q42 --> q43 with a maximal two-point lod score of 13.30 with marker D1S2649 was obtained. Haplotype analysis of flanking markers identified recombination events defining the KCS locus to a region between markers D1S2800 on the centromeric boundary and D1S2850 on the telomeric boundary, an approximately 4-cM interval. All affected individuals in these unrelated kindreds were homozygous for identical alleles at markers D1S2649 and D1S235, suggesting a single ancestral mutation underlying the disease in these families. Haploinsufficiency at 22q11, reported in another consanguineous KCS kindred, was not documented in these families.

Kenny-Caffey syndrome and microorchidism

We report on two adolescent boys with Kenny-Caffey syndrome and microorchidism. The first patient had elevated levels of serum follicle-stimulating hormone, but normal levels of luteinizing hormone and testosterone. There was no evidence of a microdeletion of the Y chromosome. The second patient had Leydig cell hyperplasia with normal seminiferous tubules and spermatogenesis, and normal pituitary histologic findings at autopsy. The presence of microorchidism in these patients confirms the previous observations and suggests subfertility, but does not fully clarify the pathogenesis.

The nanophthalmic macula

AIMS

To define an unusual macular appearance found in association with nanophthalmos.

METHODS

A case review.

RESULTS

Seven children (aged 8 months to 17 years) with nanophthalmos were examined. They all exhibited the same clinical findings of an unusual yellow macula appearance with retinal folds and crowded optic discs. Visual electrophysiology performed in four cases was normal.

CONCLUSION

A distinctive yellow macular pigmentation with associated chorioretinal folds and crowded optic discs is present in nanophthalmos. It is proposed that the retinal folds are due to a disparity between scleral and retinal growth while the macula discoloration is due to a congenital abnormality in arrangement or position of the luteal pigment and is not degenerative. Included in this case series is the second case in the literature of nanophthalmos associated with Kenny's syndrome. Inheritance of nanophthalmos appears to be autosomal recessive.

Kenny-Caffey syndrome is part of the CATCH 22 haploinsufficiency cluster

We report four sibs with Kenny-Caffey syndrome in a consanguineous Bedouin family. The first two died in the neonatal period while the remaining affected brother and sister had all the characteristic clinical, biochemical, and radiological abnormalities of the syndrome. These included severe pre- and postnatal growth retardation, cortical thickening of the tubular bones with medullary stenosis, eye abnormalities, facial dysmorphism, hypocalcaemia, and low levels of parathyroid hormone. The children also showed intracranial calcification, impaired neutrophil phagocytosis, increased proportion of B lymphocytes, reduced CD4 and CD8 subpopulations of T lymphocytes, and inhibited transformation in response to Candida antigen. Fluorescence in situ hybridisation (FISH) was applied to blood lymphocyte metaphase spreads from these two Bedouin sibs and their parents using probe D22S75 (Oncor), specific for the DiGeorge critical region on chromosome 22q11.2. The presence of 22q11.2 haploinsufficiency was identified in the affected sibs, which was transmitted from the phenotypically normal mother. The present report widens the spectrum of CATCH 22 microdeletion to accommodate Kenny-Caffey syndrome.

Anaesthetic management of the Kenny-Caffey syndrome using the laryngeal mask

We report the anaesthetic management of a nine-year-old, 6.8 kg, 75 cm tall female with the Kenny-Caffey syndrome presenting for strabismus surgery. Dysmorphic features in our patient included a hypoplastic mandible. A neonatal (size 1) laryngeal mask was successfully used for management of the airway whilst providing surgical access. The general features of this rare syndrome are presented and the literature reviewed.

Bilateral optic atrophy in Kenny's syndrome

We present a 12-year-old girl with Kenny-Caffey syndrome and bilateral optic atrophy. The results of testing in this patient and the ocular findings in the 25 previously reported cases with Kenny-Caffey syndrome are reviewed. This is the first case with such an association in the literature to date.

Kenny-Caffey syndrome in two sibs born to consanguineous parents: evidence for an autosomal recessive variant

We report on 2 sibs with manifestations of the Kenny-Caffey syndrome born to normal, consanguineous parents. Clinical manifestations included dwarfism, internal cortical thickening and medullary stenosis of tubular bones, poorly ossified skull bones, and hypocalcemia. The younger of the two died during a tonic convulsion. The older had neonatal hypoparathyroidism and is now a short intelligent, 1-year-old child. This family gives new support to the existence of an autosomal recessive variant of the syndrome.

Kenny-Caffey syndrome. Case report and literature review

Kenny-Caffey Syndrome is a rare syndrome characterized by growth retardation, uniformly small slender long bones with medullary stenosis, thickened cortex of the long bones, hypocalcemia possibly with tetany at an early age, hyperphosphatemia, ocular abnormalities, and normal intelligence. We report a child with Kenny-Caffey Syndrome and idiopathic hypoparathyroidism and present a review of the literature summarizing the reported cases of this rare syndrome.

Kenny syndrome: description of additional abnormalities and molecular studies

An 18-month-old girl presented with clinical manifestations of Kenny syndrome including growth retardation, ophthalmologic abnormalities, a persistent open anterior fontanel, dysmorphic facies, anemia, radiologic skeletal abnormalities, and severe hypoparathyroidism. Analysis of restriction patterns of DNA with human parathyroid hormone (PTH) DNA probes revealed no gross abnormalities of the PTH gene that could contribute to the hypoparathyroidism. In addition to the previously described characteristics of the syndrome, hypoplastic nails, persistent neutropenia, abnormal T cell function and neonatal liver disease all occurred and may be additional manifestations of Kenny syndrome, requiring diagnostic or therapeutic consideration.

Kenny syndrome: evidence for idiopathic hypoparathyroidism in two patients and for abnormal parathyroid hormone in one

We report three unrelated patients with Kenny syndrome. Clinical symptoms included severe dwarfism, with internal cortical thickening and medullary stenosis of the tubular bones, normal bone age, macrocephaly, absent diploic space, delayed closure of the anterior fontanel, and normal intelligence; two of the patients had hyperopia and papillary edema. The patients also had episodic hypocalcemic tetany and low serum levels of magnesium. In two patients the diagnosis of idiopathic hypoparathyroidism was established on the basis of undetectable serum parathyroid hormone (PTH) levels (N- and C-terminal RIAs); one of these had normal urinary cyclic adenosine monophosphate (cAMP) response to exogenous PTH. Circulating calcitonin was undetectable in either patient. In a third patient, who had abnormal body proportions, serum levels of PTH were increased in an RIA detecting predominantly intact PTH (N-RIA) and undetectable in another RIA recognizing carboxy-terminal fragments (C-RIA). Administration of PTH promptly increased urinary cAMP excretion. In this patient, serum levels of calcitonin were increased, whereas values for 25-OHD and 1,25(OH)2D were normal.

Unusual cause of short stature

A 24-year-old man evaluated for paresthesias and short stature was found to be hypocalcemic on initial presentation. Further evaluation showed that he had a low-normal parathormone level by amino-terminal assay, medullary stenosis of the long bones, and multiple ophthalmologic abnormalities. The remainder of his pituitary function, including growth hormone response to insulin-induced hypoglycemia, was normal. As no family history of similar findings was evident, a sporadic case of Kenny's or Kenny-Caffey syndrome was diagnosed. He became normocalcemic in response to vitamin D and calcium carbonate therapy. The results of testing in this patient and the findings in other patients previously described with the Kenny-Caffey syndrome are reviewed.

The Kenny-Caffey syndrome: growth retardation and hypocalcemia in a young boy

A 2-year-old black boy with the Kenny-Caffey syndrome was first evaluated because of growth retardation and hypocalcemia. Hypothalamic-pituitary function was normal. Basal serum somatomedin C levels were normal for age, but did not increase during short-term administration of human growth hormone. Serum immunoreactive parathyroid hormone levels remained inappropriately low during spontaneous and induced hypocalcemia, indicating that hypocalcemia was the consequence of hypoparathyroidism. The manifestations of 15 patients with this syndrome are tabulated.

The Kenny syndrome, a rare type of growth deficiency with tubular stenosis, transient hypoparathyroidism and anomalies of refraction

One family (3 cases) with the Kenny syndrome and a second family (3 cases) with features of Kenny syndrome but lacking medullary stenosis are reported. The main symptoms in both families are proportionate dwarfism, cortical thickening of tubular bones, variable anomalies of the calvaria, anemia, transient hypoparathyroidism and variable ocular anomalies. The latter include microphthalmia, and moderate-to-severe myopia or hyperopia. In the first family there was medullary stenosis of most tubular bones. In the second family two cases exhibited mild-to-moderate cortical thickening of tubular bones, but absent or mild medullary stenosis. Possible variability of the Kenny syndrome is discussed. Endocrine studies failed to demonstrate any permanent disturbance of parathormone or calcitonin metabolism, or GH deficiency. Pathogenesis remains unclear. Autosomal dominant inheritance seems to be likely.